Commit Graph

72 Commits

Author SHA1 Message Date
Gautham R. Shenoy
172100088f x86/cpufeatures: Add AMD CPPC Performance Priority feature.
Some future AMD processors have feature named "CPPC Performance
Priority" which lets userspace specify different floor performance
levels for different CPUs. The platform firmware takes these different
floor performance levels into consideration while throttling the CPUs
under power/thermal constraints. The presence of this feature is
indicated by bit 16 of the EDX register for CPUID leaf
0x80000007. More details can be found in AMD Publication titled "AMD64
Collaborative Processor Performance Control (CPPC) Performance
Priority" Revision 1.10.

Define a new feature bit named X86_FEATURE_CPPC_PERF_PRIO to map to
CPUID 0x80000007.EDX[16].

Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
2026-04-02 11:28:21 -05:00
Linus Torvalds
51d90a15fe ARM:
- Support for userspace handling of synchronous external aborts (SEAs),
   allowing the VMM to potentially handle the abort in a non-fatal
   manner.
 
 - Large rework of the VGIC's list register handling with the goal of
   supporting more active/pending IRQs than available list registers in
   hardware. In addition, the VGIC now supports EOImode==1 style
   deactivations for IRQs which may occur on a separate vCPU than the
   one that acked the IRQ.
 
 - Support for FEAT_XNX (user / privileged execute permissions) and
   FEAT_HAF (hardware update to the Access Flag) in the software page
   table walkers and shadow MMU.
 
 - Allow page table destruction to reschedule, fixing long need_resched
   latencies observed when destroying a large VM.
 
 - Minor fixes to KVM and selftests
 
 Loongarch:
 
 - Get VM PMU capability from HW GCFG register.
 
 - Add AVEC basic support.
 
 - Use 64-bit register definition for EIOINTC.
 
 - Add KVM timer test cases for tools/selftests.
 
 RISC/V:
 
 - SBI message passing (MPXY) support for KVM guest
 
 - Give a new, more specific error subcode for the case when in-kernel
   AIA virtualization fails to allocate IMSIC VS-file
 
 - Support KVM_DIRTY_LOG_INITIALLY_SET, enabling dirty log gradually
   in small chunks
 
 - Fix guest page fault within HLV* instructions
 
 - Flush VS-stage TLB after VCPU migration for Andes cores
 
 s390:
 
 - Always allocate ESCA (Extended System Control Area), instead of
   starting with the basic SCA and converting to ESCA with the
   addition of the 65th vCPU.  The price is increased number of
   exits (and worse performance) on z10 and earlier processor;
   ESCA was introduced by z114/z196 in 2010.
 
 - VIRT_XFER_TO_GUEST_WORK support
 
 - Operation exception forwarding support
 
 - Cleanups
 
 x86:
 
 - Skip the costly "zap all SPTEs" on an MMIO generation wrap if MMIO SPTE
   caching is disabled, as there can't be any relevant SPTEs to zap.
 
 - Relocate a misplaced export.
 
 - Fix an async #PF bug where KVM would clear the completion queue when the
   guest transitioned in and out of paging mode, e.g. when handling an SMI and
   then returning to paged mode via RSM.
 
 - Leave KVM's user-return notifier registered even when disabling
   virtualization, as long as kvm.ko is loaded.  On reboot/shutdown, keeping
   the notifier registered is ok; the kernel does not use the MSRs and the
   callback will run cleanly and restore host MSRs if the CPU manages to
   return to userspace before the system goes down.
 
 - Use the checked version of {get,put}_user().
 
 - Fix a long-lurking bug where KVM's lack of catch-up logic for periodic APIC
   timers can result in a hard lockup in the host.
 
 - Revert the periodic kvmclock sync logic now that KVM doesn't use a
   clocksource that's subject to NTP corrections.
 
 - Clean up KVM's handling of MMIO Stale Data and L1TF, and bury the latter
   behind CONFIG_CPU_MITIGATIONS.
 
 - Context switch XCR0, XSS, and PKRU outside of the entry/exit fast path;
   the only reason they were handled in the fast path was to paper of a bug
   in the core #MC code, and that has long since been fixed.
 
 - Add emulator support for AVX MOV instructions, to play nice with emulated
   devices whose guest drivers like to access PCI BARs with large multi-byte
   instructions.
 
 x86 (AMD):
 
 - Fix a few missing "VMCB dirty" bugs.
 
 - Fix the worst of KVM's lack of EFER.LMSLE emulation.
 
 - Add AVIC support for addressing 4k vCPUs in x2AVIC mode.
 
 - Fix incorrect handling of selective CR0 writes when checking intercepts
   during emulation of L2 instructions.
 
 - Fix a currently-benign bug where KVM would clobber SPEC_CTRL[63:32] on
   VMRUN and #VMEXIT.
 
 - Fix a bug where KVM corrupt the guest code stream when re-injecting a soft
   interrupt if the guest patched the underlying code after the VM-Exit, e.g.
   when Linux patches code with a temporary INT3.
 
 - Add KVM_X86_SNP_POLICY_BITS to advertise supported SNP policy bits to
   userspace, and extend KVM "support" to all policy bits that don't require
   any actual support from KVM.
 
 x86 (Intel):
 
 - Use the root role from kvm_mmu_page to construct EPTPs instead of the
   current vCPU state, partly as worthwhile cleanup, but mostly to pave the
   way for tracking per-root TLB flushes, and elide EPT flushes on pCPU
   migration if the root is clean from a previous flush.
 
 - Add a few missing nested consistency checks.
 
 - Rip out support for doing "early" consistency checks via hardware as the
   functionality hasn't been used in years and is no longer useful in general;
   replace it with an off-by-default module param to WARN if hardware fails
   a check that KVM does not perform.
 
 - Fix a currently-benign bug where KVM would drop the guest's SPEC_CTRL[63:32]
   on VM-Enter.
 
 - Misc cleanups.
 
 - Overhaul the TDX code to address systemic races where KVM (acting on behalf
   of userspace) could inadvertantly trigger lock contention in the TDX-Module;
   KVM was either working around these in weird, ugly ways, or was simply
   oblivious to them (though even Yan's devilish selftests could only break
   individual VMs, not the host kernel)
 
 - Fix a bug where KVM could corrupt a vCPU's cpu_list when freeing a TDX vCPU,
   if creating said vCPU failed partway through.
 
 - Fix a few sparse warnings (bad annotation, 0 != NULL).
 
 - Use struct_size() to simplify copying TDX capabilities to userspace.
 
 - Fix a bug where TDX would effectively corrupt user-return MSR values if the
   TDX Module rejects VP.ENTER and thus doesn't clobber host MSRs as expected.
 
 Selftests:
 
 - Fix a math goof in mmu_stress_test when running on a single-CPU system/VM.
 
 - Forcefully override ARCH from x86_64 to x86 to play nice with specifying
   ARCH=x86_64 on the command line.
 
 - Extend a bunch of nested VMX to validate nested SVM as well.
 
 - Add support for LA57 in the core VM_MODE_xxx macro, and add a test to
   verify KVM can save/restore nested VMX state when L1 is using 5-level
   paging, but L2 is not.
 
 - Clean up the guest paging code in anticipation of sharing the core logic for
   nested EPT and nested NPT.
 
 guest_memfd:
 
 - Add NUMA mempolicy support for guest_memfd, and clean up a variety of
   rough edges in guest_memfd along the way.
 
 - Define a CLASS to automatically handle get+put when grabbing a guest_memfd
   from a memslot to make it harder to leak references.
 
 - Enhance KVM selftests to make it easer to develop and debug selftests like
   those added for guest_memfd NUMA support, e.g. where test and/or KVM bugs
   often result in hard-to-debug SIGBUS errors.
 
 - Misc cleanups.
 
 Generic:
 
 - Use the recently-added WQ_PERCPU when creating the per-CPU workqueue for
   irqfd cleanup.
 
 - Fix a goof in the dirty ring documentation.
 
 - Fix choice of target for directed yield across different calls to
   kvm_vcpu_on_spin(); the function was always starting from the first
   vCPU instead of continuing the round-robin search.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM updates from Paolo Bonzini:
 "ARM:

   - Support for userspace handling of synchronous external aborts
     (SEAs), allowing the VMM to potentially handle the abort in a
     non-fatal manner

   - Large rework of the VGIC's list register handling with the goal of
     supporting more active/pending IRQs than available list registers
     in hardware. In addition, the VGIC now supports EOImode==1 style
     deactivations for IRQs which may occur on a separate vCPU than the
     one that acked the IRQ

   - Support for FEAT_XNX (user / privileged execute permissions) and
     FEAT_HAF (hardware update to the Access Flag) in the software page
     table walkers and shadow MMU

   - Allow page table destruction to reschedule, fixing long
     need_resched latencies observed when destroying a large VM

   - Minor fixes to KVM and selftests

  Loongarch:

   - Get VM PMU capability from HW GCFG register

   - Add AVEC basic support

   - Use 64-bit register definition for EIOINTC

   - Add KVM timer test cases for tools/selftests

  RISC/V:

   - SBI message passing (MPXY) support for KVM guest

   - Give a new, more specific error subcode for the case when in-kernel
     AIA virtualization fails to allocate IMSIC VS-file

   - Support KVM_DIRTY_LOG_INITIALLY_SET, enabling dirty log gradually
     in small chunks

   - Fix guest page fault within HLV* instructions

   - Flush VS-stage TLB after VCPU migration for Andes cores

  s390:

   - Always allocate ESCA (Extended System Control Area), instead of
     starting with the basic SCA and converting to ESCA with the
     addition of the 65th vCPU. The price is increased number of exits
     (and worse performance) on z10 and earlier processor; ESCA was
     introduced by z114/z196 in 2010

   - VIRT_XFER_TO_GUEST_WORK support

   - Operation exception forwarding support

   - Cleanups

  x86:

   - Skip the costly "zap all SPTEs" on an MMIO generation wrap if MMIO
     SPTE caching is disabled, as there can't be any relevant SPTEs to
     zap

   - Relocate a misplaced export

   - Fix an async #PF bug where KVM would clear the completion queue
     when the guest transitioned in and out of paging mode, e.g. when
     handling an SMI and then returning to paged mode via RSM

   - Leave KVM's user-return notifier registered even when disabling
     virtualization, as long as kvm.ko is loaded. On reboot/shutdown,
     keeping the notifier registered is ok; the kernel does not use the
     MSRs and the callback will run cleanly and restore host MSRs if the
     CPU manages to return to userspace before the system goes down

   - Use the checked version of {get,put}_user()

   - Fix a long-lurking bug where KVM's lack of catch-up logic for
     periodic APIC timers can result in a hard lockup in the host

   - Revert the periodic kvmclock sync logic now that KVM doesn't use a
     clocksource that's subject to NTP corrections

   - Clean up KVM's handling of MMIO Stale Data and L1TF, and bury the
     latter behind CONFIG_CPU_MITIGATIONS

   - Context switch XCR0, XSS, and PKRU outside of the entry/exit fast
     path; the only reason they were handled in the fast path was to
     paper of a bug in the core #MC code, and that has long since been
     fixed

   - Add emulator support for AVX MOV instructions, to play nice with
     emulated devices whose guest drivers like to access PCI BARs with
     large multi-byte instructions

  x86 (AMD):

   - Fix a few missing "VMCB dirty" bugs

   - Fix the worst of KVM's lack of EFER.LMSLE emulation

   - Add AVIC support for addressing 4k vCPUs in x2AVIC mode

   - Fix incorrect handling of selective CR0 writes when checking
     intercepts during emulation of L2 instructions

   - Fix a currently-benign bug where KVM would clobber SPEC_CTRL[63:32]
     on VMRUN and #VMEXIT

   - Fix a bug where KVM corrupt the guest code stream when re-injecting
     a soft interrupt if the guest patched the underlying code after the
     VM-Exit, e.g. when Linux patches code with a temporary INT3

   - Add KVM_X86_SNP_POLICY_BITS to advertise supported SNP policy bits
     to userspace, and extend KVM "support" to all policy bits that
     don't require any actual support from KVM

  x86 (Intel):

   - Use the root role from kvm_mmu_page to construct EPTPs instead of
     the current vCPU state, partly as worthwhile cleanup, but mostly to
     pave the way for tracking per-root TLB flushes, and elide EPT
     flushes on pCPU migration if the root is clean from a previous
     flush

   - Add a few missing nested consistency checks

   - Rip out support for doing "early" consistency checks via hardware
     as the functionality hasn't been used in years and is no longer
     useful in general; replace it with an off-by-default module param
     to WARN if hardware fails a check that KVM does not perform

   - Fix a currently-benign bug where KVM would drop the guest's
     SPEC_CTRL[63:32] on VM-Enter

   - Misc cleanups

   - Overhaul the TDX code to address systemic races where KVM (acting
     on behalf of userspace) could inadvertantly trigger lock contention
     in the TDX-Module; KVM was either working around these in weird,
     ugly ways, or was simply oblivious to them (though even Yan's
     devilish selftests could only break individual VMs, not the host
     kernel)

   - Fix a bug where KVM could corrupt a vCPU's cpu_list when freeing a
     TDX vCPU, if creating said vCPU failed partway through

   - Fix a few sparse warnings (bad annotation, 0 != NULL)

   - Use struct_size() to simplify copying TDX capabilities to userspace

   - Fix a bug where TDX would effectively corrupt user-return MSR
     values if the TDX Module rejects VP.ENTER and thus doesn't clobber
     host MSRs as expected

  Selftests:

   - Fix a math goof in mmu_stress_test when running on a single-CPU
     system/VM

   - Forcefully override ARCH from x86_64 to x86 to play nice with
     specifying ARCH=x86_64 on the command line

   - Extend a bunch of nested VMX to validate nested SVM as well

   - Add support for LA57 in the core VM_MODE_xxx macro, and add a test
     to verify KVM can save/restore nested VMX state when L1 is using
     5-level paging, but L2 is not

   - Clean up the guest paging code in anticipation of sharing the core
     logic for nested EPT and nested NPT

  guest_memfd:

   - Add NUMA mempolicy support for guest_memfd, and clean up a variety
     of rough edges in guest_memfd along the way

   - Define a CLASS to automatically handle get+put when grabbing a
     guest_memfd from a memslot to make it harder to leak references

   - Enhance KVM selftests to make it easer to develop and debug
     selftests like those added for guest_memfd NUMA support, e.g. where
     test and/or KVM bugs often result in hard-to-debug SIGBUS errors

   - Misc cleanups

  Generic:

   - Use the recently-added WQ_PERCPU when creating the per-CPU
     workqueue for irqfd cleanup

   - Fix a goof in the dirty ring documentation

   - Fix choice of target for directed yield across different calls to
     kvm_vcpu_on_spin(); the function was always starting from the first
     vCPU instead of continuing the round-robin search"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (260 commits)
  KVM: arm64: at: Update AF on software walk only if VM has FEAT_HAFDBS
  KVM: arm64: at: Use correct HA bit in TCR_EL2 when regime is EL2
  KVM: arm64: Document KVM_PGTABLE_PROT_{UX,PX}
  KVM: arm64: Fix spelling mistake "Unexpeced" -> "Unexpected"
  KVM: arm64: Add break to default case in kvm_pgtable_stage2_pte_prot()
  KVM: arm64: Add endian casting to kvm_swap_s[12]_desc()
  KVM: arm64: Fix compilation when CONFIG_ARM64_USE_LSE_ATOMICS=n
  KVM: arm64: selftests: Add test for AT emulation
  KVM: arm64: nv: Expose hardware access flag management to NV guests
  KVM: arm64: nv: Implement HW access flag management in stage-2 SW PTW
  KVM: arm64: Implement HW access flag management in stage-1 SW PTW
  KVM: arm64: Propagate PTW errors up to AT emulation
  KVM: arm64: Add helper for swapping guest descriptor
  KVM: arm64: nv: Use pgtable definitions in stage-2 walk
  KVM: arm64: Handle endianness in read helper for emulated PTW
  KVM: arm64: nv: Stop passing vCPU through void ptr in S2 PTW
  KVM: arm64: Call helper for reading descriptors directly
  KVM: arm64: nv: Advertise support for FEAT_XNX
  KVM: arm64: Teach ptdump about FEAT_XNX permissions
  KVM: s390: Use generic VIRT_XFER_TO_GUEST_WORK functions
  ...
2025-12-05 17:01:20 -08:00
Linus Torvalds
d61f1cc5db * Enable Linear Address Space Separation (LASS)
* Change X86_FEATURE leaf 17 from an AMD leaf to Linux-defined
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Merge tag 'x86_cpu_for_6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 CPU feature updates from Dave Hansen:
 "The biggest thing of note here is Linear Address Space Separation
  (LASS). It represents the first time I can think of that the
  upper=>kernel/lower=>user address space convention is actually
  recognized by the hardware on x86. It ensures that userspace can not
  even get the hardware to _start_ page walks for the kernel address
  space. This, of course, is a really nice generic side channel defense.

  This is really only a down payment on LASS support. There are still
  some details to work out in its interaction with EFI calls and
  vsyscall emulation. For now, LASS is disabled if either of those
  features is compiled in (which is almost always the case).

  There's also one straggler commit in here which converts an
  under-utilized AMD CPU feature leaf into a generic Linux-defined leaf
  so more feature can be packed in there.

  Summary:

   - Enable Linear Address Space Separation (LASS)

   - Change X86_FEATURE leaf 17 from an AMD leaf to Linux-defined"

* tag 'x86_cpu_for_6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpu: Enable LASS during CPU initialization
  selftests/x86: Update the negative vsyscall tests to expect a #GP
  x86/traps: Communicate a LASS violation in #GP message
  x86/kexec: Disable LASS during relocate kernel
  x86/alternatives: Disable LASS when patching kernel code
  x86/asm: Introduce inline memcpy and memset
  x86/cpu: Add an LASS dependency on SMAP
  x86/cpufeatures: Enumerate the LASS feature bits
  x86/cpufeatures: Make X86_FEATURE leaf 17 Linux-specific
2025-12-02 14:48:08 -08:00
Linus Torvalds
54de197c9a * Allow security version (SVN) updates so enclaves can attest
to new microcode.
  * Fix kernel docs typos
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Merge tag 'x86_sgx_for_6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 SGX updates from Dave HansenL
 "The main content here is adding support for the new EUPDATESVN SGX
  ISA. Before this, folks who updated microcode had to reboot before
  enclaves could attest to the new microcode. The new functionality lets
  them do this without a reboot.

  The rest are some nice, but relatively mundane comment and kernel-doc
  fixups.

  Summary:

   - Allow security version (SVN) updates so enclaves can attest to new
     microcode

   - Fix kernel docs typos"

* tag 'x86_sgx_for_6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/sgx: Fix a typo in the kernel-doc comment for enum sgx_attribute
  x86/sgx: Remove superfluous asterisk from copyright comment in asm/sgx.h
  x86/sgx: Document structs and enums with '@', not '%'
  x86/sgx: Add kernel-doc descriptions for params passed to vDSO user handler
  x86/sgx: Add a missing colon in kernel-doc markup for "struct sgx_enclave_run"
  x86/sgx: Enable automatic SVN updates for SGX enclaves
  x86/sgx: Implement ENCLS[EUPDATESVN]
  x86/sgx: Define error codes for use by ENCLS[EUPDATESVN]
  x86/cpufeatures: Add X86_FEATURE_SGX_EUPDATESVN feature flag
  x86/sgx: Introduce functions to count the sgx_(vepc_)open()
2025-12-02 14:03:05 -08:00
Babu Moger
3767def18f x86/cpufeatures: Add support for L3 Smart Data Cache Injection Allocation Enforcement
Smart Data Cache Injection (SDCI) is a mechanism that enables direct insertion
of data from I/O devices into the L3 cache. By directly caching data from I/O
devices rather than first storing the I/O data in DRAM, SDCI reduces demands on
DRAM bandwidth and reduces latency to the processor consuming the I/O data.

The SDCIAE (SDCI Allocation Enforcement) PQE feature allows system software to
control the portion of the L3 cache used for SDCI.

When enabled, SDCIAE forces all SDCI lines to be placed into the L3 cache
partitions identified by the highest-supported L3_MASK_n register, where n is
the maximum supported CLOSID.

Add CPUID feature bit that can be used to configure SDCIAE.

The SDCIAE feature details are documented in:

  AMD64 Architecture Programmer's Manual Volume 2: System Programming
     Publication # 24593 Revision 3.41 section 19.4.7 L3 Smart Data Cache
    Injection Allocation Enforcement (SDCIAE).

available at https://bugzilla.kernel.org/show_bug.cgi?id=206537

Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://patch.msgid.link/83ca10d981c48e86df2c3ad9658bb3ba3544c763.1762995456.git.babu.moger@amd.com
2025-11-21 22:03:07 +01:00
Naveen N Rao
5d0316e25d x86/cpufeatures: Add X86_FEATURE_X2AVIC_EXT
Add CPUID feature bit for x2AVIC extension that enables AMD SVM to
support up to 4096 vCPUs in x2AVIC mode. The primary change is in the
size of the AVIC Physical ID table, which can now go up to 8 contiguous
4k pages. The number of pages allocated is controlled by the maximum
APIC ID for a guest, and that controls the number of pages to allocate
for the AVIC Physical ID table. AVIC hardware is enhanced to look up
Physical ID table entries for vCPUs > 512 for locating the target APIC
backing page and the host APIC ID of the physical core on which the
guest vCPU is running.

Signed-off-by: Naveen N Rao (AMD) <naveen@kernel.org>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/e5c9c471ab99a130bf9b728b77050ab308cf8624.1757009416.git.naveen@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-10-17 15:23:45 -07:00
Elena Reshetova
6ffdb49101 x86/cpufeatures: Add X86_FEATURE_SGX_EUPDATESVN feature flag
Add a flag indicating whenever ENCLS[EUPDATESVN] SGX instruction is
supported. This will be used by SGX driver to perform CPU SVN updates.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Nataliia Bondarevska <bondarn@google.com>
2025-10-16 14:42:08 -07:00
Borislav Petkov (AMD)
ddde4abaa0 x86/cpufeatures: Make X86_FEATURE leaf 17 Linux-specific
That cpuinfo_x86.x86_capability[] element was supposed to mirror CPUID flags
from CPUID_0x80000007_EBX but that leaf has still to this day only three bits
defined in it. So move those bits to scattered.c and free the capability
element for synthetic flags.

No functional changes.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
2025-10-13 16:21:25 +02:00
Linus Torvalds
256e341706 Generic:
* Rework almost all of KVM's exports to expose symbols only to KVM's x86
   vendor modules (kvm-{amd,intel}.ko and PPC's kvm-{pr,hv}.ko.
 
 x86:
 
 * Rework almost all of KVM x86's exports to expose symbols only to KVM's
   vendor modules, i.e. to kvm-{amd,intel}.ko.
 
 * Add support for virtualizing Control-flow Enforcement Technology (CET) on
   Intel (Shadow Stacks and Indirect Branch Tracking) and AMD (Shadow Stacks).
   It's worth noting that while SHSTK and IBT can be enabled separately in CPUID,
   it is not really possible to virtualize them separately.  Therefore, Intel
   processors will really allow both SHSTK and IBT under the hood if either is
   made visible in the guest's CPUID.  The alternative would be to intercept
   XSAVES/XRSTORS, which is not feasible for performance reasons.
 
 * Fix a variety of fuzzing WARNs all caused by checking L1 intercepts when
   completing userspace I/O.  KVM has already committed to allowing L2 to
   to perform I/O at that point.
 
 * Emulate PERF_CNTR_GLOBAL_STATUS_SET for PerfMonV2 guests, as the MSR is
   supposed to exist for v2 PMUs.
 
 * Allow Centaur CPU leaves (base 0xC000_0000) for Zhaoxin CPUs.
 
 * Add support for the immediate forms of RDMSR and WRMSRNS, sans full
   emulator support (KVM should never need to emulate the MSRs outside of
   forced emulation and other contrived testing scenarios).
 
 * Clean up the MSR APIs in preparation for CET and FRED virtualization, as
   well as mediated vPMU support.
 
 * Clean up a pile of PMU code in anticipation of adding support for mediated
   vPMUs.
 
 * Reject in-kernel IOAPIC/PIT for TDX VMs, as KVM can't obtain EOI vmexits
   needed to faithfully emulate an I/O APIC for such guests.
 
 * Many cleanups and minor fixes.
 
 * Recover possible NX huge pages within the TDP MMU under read lock to
   reduce guest jitter when restoring NX huge pages.
 
 * Return -EAGAIN during prefault if userspace concurrently deletes/moves the
   relevant memslot, to fix an issue where prefaulting could deadlock with the
   memslot update.
 
 x86 (AMD):
 
 * Enable AVIC by default for Zen4+ if x2AVIC (and other prereqs) is supported.
 
 * Require a minimum GHCB version of 2 when starting SEV-SNP guests via
   KVM_SEV_INIT2 so that invalid GHCB versions result in immediate errors
   instead of latent guest failures.
 
 * Add support for SEV-SNP's CipherText Hiding, an opt-in feature that prevents
   unauthorized CPU accesses from reading the ciphertext of SNP guest private
   memory, e.g. to attempt an offline attack.  This feature splits the shared
   SEV-ES/SEV-SNP ASID space into separate ranges for SEV-ES and SEV-SNP guests,
   therefore a new module parameter is needed to control the number of ASIDs
   that can be used for VMs with CipherText Hiding vs. how many can be used to
   run SEV-ES guests.
 
 * Add support for Secure TSC for SEV-SNP guests, which prevents the untrusted
   host from tampering with the guest's TSC frequency, while still allowing the
   the VMM to configure the guest's TSC frequency prior to launch.
 
 * Validate the XCR0 provided by the guest (via the GHCB) to avoid bugs
   resulting from bogus XCR0 values.
 
 * Save an SEV guest's policy if and only if LAUNCH_START fully succeeds to
   avoid leaving behind stale state (thankfully not consumed in KVM).
 
 * Explicitly reject non-positive effective lengths during SNP's LAUNCH_UPDATE
   instead of subtly relying on guest_memfd to deal with them.
 
 * Reload the pre-VMRUN TSC_AUX on #VMEXIT for SEV-ES guests, not the host's
   desired TSC_AUX, to fix a bug where KVM was keeping a different vCPU's
   TSC_AUX in the host MSR until return to userspace.
 
 KVM (Intel):
 
 * Preparation for FRED support.
 
 * Don't retry in TDX's anti-zero-step mitigation if the target memslot is
   invalid, i.e. is being deleted or moved, to fix a deadlock scenario similar
   to the aforementioned prefaulting case.
 
 * Misc bugfixes and minor cleanups.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull x86 kvm updates from Paolo Bonzini:
 "Generic:

   - Rework almost all of KVM's exports to expose symbols only to KVM's
     x86 vendor modules (kvm-{amd,intel}.ko and PPC's kvm-{pr,hv}.ko

  x86:

   - Rework almost all of KVM x86's exports to expose symbols only to
     KVM's vendor modules, i.e. to kvm-{amd,intel}.ko

   - Add support for virtualizing Control-flow Enforcement Technology
     (CET) on Intel (Shadow Stacks and Indirect Branch Tracking) and AMD
     (Shadow Stacks).

     It is worth noting that while SHSTK and IBT can be enabled
     separately in CPUID, it is not really possible to virtualize them
     separately. Therefore, Intel processors will really allow both
     SHSTK and IBT under the hood if either is made visible in the
     guest's CPUID. The alternative would be to intercept
     XSAVES/XRSTORS, which is not feasible for performance reasons

   - Fix a variety of fuzzing WARNs all caused by checking L1 intercepts
     when completing userspace I/O. KVM has already committed to
     allowing L2 to to perform I/O at that point

   - Emulate PERF_CNTR_GLOBAL_STATUS_SET for PerfMonV2 guests, as the
     MSR is supposed to exist for v2 PMUs

   - Allow Centaur CPU leaves (base 0xC000_0000) for Zhaoxin CPUs

   - Add support for the immediate forms of RDMSR and WRMSRNS, sans full
     emulator support (KVM should never need to emulate the MSRs outside
     of forced emulation and other contrived testing scenarios)

   - Clean up the MSR APIs in preparation for CET and FRED
     virtualization, as well as mediated vPMU support

   - Clean up a pile of PMU code in anticipation of adding support for
     mediated vPMUs

   - Reject in-kernel IOAPIC/PIT for TDX VMs, as KVM can't obtain EOI
     vmexits needed to faithfully emulate an I/O APIC for such guests

   - Many cleanups and minor fixes

   - Recover possible NX huge pages within the TDP MMU under read lock
     to reduce guest jitter when restoring NX huge pages

   - Return -EAGAIN during prefault if userspace concurrently
     deletes/moves the relevant memslot, to fix an issue where
     prefaulting could deadlock with the memslot update

  x86 (AMD):

   - Enable AVIC by default for Zen4+ if x2AVIC (and other prereqs) is
     supported

   - Require a minimum GHCB version of 2 when starting SEV-SNP guests
     via KVM_SEV_INIT2 so that invalid GHCB versions result in immediate
     errors instead of latent guest failures

   - Add support for SEV-SNP's CipherText Hiding, an opt-in feature that
     prevents unauthorized CPU accesses from reading the ciphertext of
     SNP guest private memory, e.g. to attempt an offline attack. This
     feature splits the shared SEV-ES/SEV-SNP ASID space into separate
     ranges for SEV-ES and SEV-SNP guests, therefore a new module
     parameter is needed to control the number of ASIDs that can be used
     for VMs with CipherText Hiding vs. how many can be used to run
     SEV-ES guests

   - Add support for Secure TSC for SEV-SNP guests, which prevents the
     untrusted host from tampering with the guest's TSC frequency, while
     still allowing the the VMM to configure the guest's TSC frequency
     prior to launch

   - Validate the XCR0 provided by the guest (via the GHCB) to avoid
     bugs resulting from bogus XCR0 values

   - Save an SEV guest's policy if and only if LAUNCH_START fully
     succeeds to avoid leaving behind stale state (thankfully not
     consumed in KVM)

   - Explicitly reject non-positive effective lengths during SNP's
     LAUNCH_UPDATE instead of subtly relying on guest_memfd to deal with
     them

   - Reload the pre-VMRUN TSC_AUX on #VMEXIT for SEV-ES guests, not the
     host's desired TSC_AUX, to fix a bug where KVM was keeping a
     different vCPU's TSC_AUX in the host MSR until return to userspace

  KVM (Intel):

   - Preparation for FRED support

   - Don't retry in TDX's anti-zero-step mitigation if the target
     memslot is invalid, i.e. is being deleted or moved, to fix a
     deadlock scenario similar to the aforementioned prefaulting case

   - Misc bugfixes and minor cleanups"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (142 commits)
  KVM: x86: Export KVM-internal symbols for sub-modules only
  KVM: x86: Drop pointless exports of kvm_arch_xxx() hooks
  KVM: x86: Move kvm_intr_is_single_vcpu() to lapic.c
  KVM: Export KVM-internal symbols for sub-modules only
  KVM: s390/vfio-ap: Use kvm_is_gpa_in_memslot() instead of open coded equivalent
  KVM: VMX: Make CR4.CET a guest owned bit
  KVM: selftests: Verify MSRs are (not) in save/restore list when (un)supported
  KVM: selftests: Add coverage for KVM-defined registers in MSRs test
  KVM: selftests: Add KVM_{G,S}ET_ONE_REG coverage to MSRs test
  KVM: selftests: Extend MSRs test to validate vCPUs without supported features
  KVM: selftests: Add support for MSR_IA32_{S,U}_CET to MSRs test
  KVM: selftests: Add an MSR test to exercise guest/host and read/write
  KVM: x86: Define AMD's #HV, #VC, and #SX exception vectors
  KVM: x86: Define Control Protection Exception (#CP) vector
  KVM: x86: Add human friendly formatting for #XM, and #VE
  KVM: SVM: Enable shadow stack virtualization for SVM
  KVM: SEV: Synchronize MSR_IA32_XSS from the GHCB when it's valid
  KVM: SVM: Pass through shadow stack MSRs as appropriate
  KVM: SVM: Update dump_vmcb with shadow stack save area additions
  KVM: nSVM: Save/load CET Shadow Stack state to/from vmcb12/vmcb02
  ...
2025-10-06 12:37:34 -07:00
Babu Moger
e19c062199 x86/cpufeatures: Add support for Assignable Bandwidth Monitoring Counters (ABMC)
Users can create as many monitor groups as RMIDs supported by the hardware.
However, the bandwidth monitoring feature on AMD only guarantees that RMIDs
currently assigned to a processor will be tracked by hardware. The counters of
any other RMIDs which are no longer being tracked will be reset to zero.

The MBM event counters return "Unavailable" for the RMIDs that are not tracked
by hardware. So, there can be only limited number of groups that can give
guaranteed monitoring numbers. With ever changing configurations there is no
way to definitely know which of these groups are being tracked during
a particular time. Users do not have the option to monitor a group or set of
groups for a certain period of time without worrying about RMID being reset in
between.

The ABMC feature allows users to assign a hardware counter to an RMID, event
pair and monitor bandwidth usage as long as it is assigned. The hardware
continues to track the assigned counter until it is explicitly unassigned by
the user. There is no need to worry about counters being reset during this
period. Additionally, the user can specify the type of memory transactions
(e.g., reads, writes) for the counter to track.

Without ABMC enabled, monitoring will work in current mode without assignment
option.

The Linux resctrl subsystem provides an interface that allows monitoring of up
to two memory bandwidth events per group, selected from a combination of
available total and local events. When ABMC is enabled, two events will be
assigned to each group by default, in line with the current interface design.
Users will also have the option to configure which types of memory
transactions are counted by these events.

Due to the limited number of available counters (32), users may quickly
exhaust the available counters. If the system runs out of assignable ABMC
counters, the kernel will report an error. In such cases, users will need to
unassign one or more active counters to free up counters for new assignments.
resctrl will provide options to assign or unassign events through the
group-specific interface file.

The feature is detected via CPUID_Fn80000020_EBX_x00 bit 5: ABMC (Assignable
Bandwidth Monitoring Counters).

The ABMC feature details are documented in APM [1] available from [2]. [1]
AMD64 Architecture Programmer's Manual Volume 2: System Programming
Publication # 24593 Revision 3.41 section 19.3.3.3 Assignable Bandwidth
Monitoring (ABMC).

  [ bp: Massage commit message, fixup enumeration due to VMSCAPE ]

Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537 # [2]
2025-09-15 12:04:15 +02:00
Xin Li
3c7cb84145 x86/cpufeatures: Add a CPU feature bit for MSR immediate form instructions
The immediate form of MSR access instructions are primarily motivated
by performance, not code size: by having the MSR number in an immediate,
it is available *much* earlier in the pipeline, which allows the
hardware much more leeway about how a particular MSR is handled.

Use a scattered CPU feature bit for MSR immediate form instructions.

Suggested-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
Link: https://lore.kernel.org/r/20250805202224.1475590-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-08-19 11:59:44 -07:00
Tom Lendacky
7b306dfa32 x86/sev: Evict cache lines during SNP memory validation
An SNP cache coherency vulnerability requires a cache line eviction
mitigation when validating memory after a page state change to private.
The specific mitigation is to touch the first and last byte of each 4K
page that is being validated. There is no need to perform the mitigation
when performing a page state change to shared and rescinding validation.

CPUID bit Fn8000001F_EBX[31] defines the COHERENCY_SFW_NO CPUID bit
that, when set, indicates that the software mitigation for this
vulnerability is not needed.

Implement the mitigation and invoke it when validating memory (making it
private) and the COHERENCY_SFW_NO bit is not set, indicating the SNP
guest is vulnerable.

Co-developed-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
2025-08-06 19:17:22 +02:00
Borislav Petkov (AMD)
d8010d4ba4 x86/bugs: Add a Transient Scheduler Attacks mitigation
Add the required features detection glue to bugs.c et all in order to
support the TSA mitigation.

Co-developed-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
2025-06-17 17:17:02 +02:00
Chang S. Bae
b02dc185ee x86/cpufeatures: Add X86_FEATURE_APX
Intel Advanced Performance Extensions (APX) introduce a new set of
general-purpose registers, managed as an extended state component via the
xstate management facility.

Before enabling this new xstate, define a feature flag to clarify the
dependency in xsave_cpuid_features[]. APX is enumerated under CPUID level
7 with EDX=1. Since this CPUID leaf is not yet allocated, place the flag
in a scattered feature word.

While this feature is intended only for userspace, exposing it via
/proc/cpuinfo is unnecessary. Instead, the existing arch_prctl(2)
mechanism with the ARCH_GET_XCOMP_SUPP option can be used to query the
feature availability.

Finally, clarify that APX depends on XSAVE.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20250416021720.12305-2-chang.seok.bae@intel.com
2025-04-16 09:44:13 +02:00
Xin Li (Intel)
3aba0b40ca x86/cpufeatures: Shorten X86_FEATURE_AMD_HETEROGENEOUS_CORES
Shorten X86_FEATURE_AMD_HETEROGENEOUS_CORES to X86_FEATURE_AMD_HTR_CORES
to make the last column aligned consistently in the whole file.

No functional changes.

Suggested-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250415175410.2944032-4-xin@zytor.com
2025-04-15 22:09:20 +02:00
Borislav Petkov (AMD)
e6e6a303f8 x86/cpu: Fix formatting of cpuid_bits[] in scattered.c
Realign initializers to accomodate for longer X86_FEATURE define names.

No functional changes.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
2024-10-28 13:51:05 +01:00
Perry Yuan
0c487010cb x86/cpufeatures: Add X86_FEATURE_AMD_WORKLOAD_CLASS feature bit
Add a new feature bit that indicates support for workload-based heuristic
feedback to OS for scheduling decisions.

When the bit set, threads are classified during runtime into enumerated
classes. The classes represent thread performance/power characteristics
that may benefit from special scheduling behaviors.

Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Link: https://lore.kernel.org/r/20241028020251.8085-4-mario.limonciello@amd.com
2024-10-28 13:44:44 +01:00
Perry Yuan
1ad4667066 x86/cpufeatures: Add X86_FEATURE_AMD_HETEROGENEOUS_CORES
CPUID leaf 0x80000026 advertises core types with different efficiency
rankings.

Bit 30 indicates the heterogeneous core topology feature, if the bit
set, it means not all instances at the current hierarchical level have
the same core topology.

This is described in the AMD64 Architecture Programmers Manual Volume
2 and 3, doc ID #25493 and #25494.

Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20241025171459.1093-3-mario.limonciello@amd.com
2024-10-25 20:31:16 +02:00
Mario Limonciello
104edc6efc x86/cpufeatures: Rename X86_FEATURE_FAST_CPPC to have AMD prefix
This feature is an AMD unique feature of some processors, so put
AMD into the name.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20241025171459.1093-2-mario.limonciello@amd.com
2024-10-25 20:09:16 +02:00
Perry Yuan
c7107750b2 x86/cpufeatures: Add AMD FAST CPPC feature flag
Some AMD Zen 4 processors support a new feature FAST CPPC which
allows for a faster CPPC loop due to internal architectural
enhancements. The goal of this faster loop is higher performance
at the same power consumption.

Reference:
See the page 99 of PPR for AMD Family 19h Model 61h rev.B1, docID 56713

Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Xiaojian Du <Xiaojian.Du@amd.com>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
2024-06-11 16:12:12 -05:00
Daniel Sneddon
0f4a837615 x86/bhi: Define SPEC_CTRL_BHI_DIS_S
Newer processors supports a hardware control BHI_DIS_S to mitigate
Branch History Injection (BHI). Setting BHI_DIS_S protects the kernel
from userspace BHI attacks without having to manually overwrite the
branch history.

Define MSR_SPEC_CTRL bit BHI_DIS_S and its enumeration CPUID.BHI_CTRL.
Mitigation is enabled later.

Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
2024-04-08 19:27:05 +02:00
Sandipan Das
598c2fafc0 perf/x86/amd/lbr: Use freeze based on availability
Currently, the LBR code assumes that LBR Freeze is supported on all processors
when X86_FEATURE_AMD_LBR_V2 is available i.e. CPUID leaf 0x80000022[EAX]
bit 1 is set. This is incorrect as the availability of the feature is
additionally dependent on CPUID leaf 0x80000022[EAX] bit 2 being set,
which may not be set for all Zen 4 processors.

Define a new feature bit for LBR and PMC freeze and set the freeze enable bit
(FLBRI) in DebugCtl (MSR 0x1d9) conditionally.

It should still be possible to use LBR without freeze for profile-guided
optimization of user programs by using an user-only branch filter during
profiling. When the user-only filter is enabled, branches are no longer
recorded after the transition to CPL 0 upon PMI arrival. When branch
entries are read in the PMI handler, the branch stack does not change.

E.g.

  $ perf record -j any,u -e ex_ret_brn_tkn ./workload

Since the feature bit is visible under flags in /proc/cpuinfo, it can be
used to determine the feasibility of use-cases which require LBR Freeze
to be supported by the hardware such as profile-guided optimization of
kernels.

Fixes: ca5b7c0d96 ("perf/x86/amd/lbr: Add LbrExtV2 branch record support")
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/69a453c97cfd11c6f2584b19f937fe6df741510f.1711091584.git.sandipan.das@amd.com
2024-03-25 11:16:55 +01:00
Babu Moger
78335aac61 x86/cpufeatures: Add Bandwidth Monitoring Event Configuration feature flag
Newer AMD processors support the new feature Bandwidth Monitoring Event
Configuration (BMEC).

The feature support is identified via CPUID Fn8000_0020_EBX_x0[3]: EVT_CFG -
Bandwidth Monitoring Event Configuration (BMEC)

The bandwidth monitoring events mbm_total_bytes and mbm_local_bytes are set to
count all the total and local reads/writes, respectively. With the introduction
of slow memory, the two counters are not enough to count all the different types
of memory events. Therefore, BMEC provides the option to configure
mbm_total_bytes and mbm_local_bytes to count the specific type of events.

Each BMEC event has a configuration MSR which contains one field for each
bandwidth type that can be used to configure the bandwidth event to track any
combination of supported bandwidth types. The event will count requests from
every bandwidth type bit that is set in the corresponding configuration
register.

Following are the types of events supported:

  ====    ========================================================
  Bits    Description
  ====    ========================================================
  6       Dirty Victims from the QOS domain to all types of memory
  5       Reads to slow memory in the non-local NUMA domain
  4       Reads to slow memory in the local NUMA domain
  3       Non-temporal writes to non-local NUMA domain
  2       Non-temporal writes to local NUMA domain
  1       Reads to memory in the non-local NUMA domain
  0       Reads to memory in the local NUMA domain
  ====    ========================================================

By default, the mbm_total_bytes configuration is set to 0x7F to count
all the event types and the mbm_local_bytes configuration is set to 0x15 to
count all the local memory events.

Feature description is available in the specification, "AMD64 Technology
Platform Quality of Service Extensions, Revision: 1.03 Publication" at
https://bugzilla.kernel.org/attachment.cgi?id=301365

Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/20230113152039.770054-5-babu.moger@amd.com
2023-01-23 17:38:31 +01:00
Babu Moger
f334f723a6 x86/cpufeatures: Add Slow Memory Bandwidth Allocation feature flag
Add the new AMD feature X86_FEATURE_SMBA. With it, the QOS enforcement policies
can be applied to external slow memory connected to the host. QOS enforcement is
accomplished by assigning a Class Of Service (COS) to a processor and specifying
allocations or limits for that COS for each resource to be allocated.

This feature is identified by the CPUID function 0x8000_0020_EBX_x0[2]:
L3SBE - L3 external slow memory bandwidth enforcement.

CXL.memory is the only supported "slow" memory device. With SMBA, the hardware
enables bandwidth allocation on the slow memory devices.  If there are multiple
slow memory devices in the system, then the throttling logic groups all the slow
sources together and applies the limit on them as a whole.

The presence of the SMBA feature (with CXL.memory) is independent of whether
slow memory device is actually present in the system. If there is no slow memory
in the system, then setting a SMBA limit will have no impact on the performance
of the system.

Presence of CXL memory can be identified by the numactl command:

  $numactl -H
  available: 2 nodes (0-1)
  node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
  node 0 size: 63678 MB node 0 free: 59542 MB
  node 1 cpus:
  node 1 size: 16122 MB
  node 1 free: 15627 MB
  node distances:
  node   0   1
     0:  10  50
     1:  50  10

CPU list for CXL memory will be empty. The cpu-cxl node distance is greater than
cpu-to-cpu distances. Node 1 has the CXL memory in this case. CXL memory can
also be identified using ACPI SRAT table and memory maps.

Feature description is available in the specification, "AMD64 Technology
Platform Quality of Service Extensions, Revision: 1.03 Publication # 56375
Revision: 1.03 Issue Date: February 2022" at
https://bugzilla.kernel.org/attachment.cgi?id=301365

See also https://www.amd.com/en/support/tech-docs/amd64-technology-platform-quality-service-extensions

Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/20230113152039.770054-3-babu.moger@amd.com
2023-01-23 17:38:17 +01:00
Kai Huang
16a7fe3728 KVM/VMX: Allow exposing EDECCSSA user leaf function to KVM guest
The new Asynchronous Exit (AEX) notification mechanism (AEX-notify)
allows one enclave to receive a notification in the ERESUME after the
enclave exit due to an AEX.  EDECCSSA is a new SGX user leaf function
(ENCLU[EDECCSSA]) to facilitate the AEX notification handling.  The new
EDECCSSA is enumerated via CPUID(EAX=0x12,ECX=0x0):EAX[11].

Besides Allowing reporting the new AEX-notify attribute to KVM guests,
also allow reporting the new EDECCSSA user leaf function to KVM guests
so the guest can fully utilize the AEX-notify mechanism.

Similar to existing X86_FEATURE_SGX1 and X86_FEATURE_SGX2, introduce a
new scattered X86_FEATURE_SGX_EDECCSSA bit for the new EDECCSSA, and
report it in KVM's supported CPUIDs.

Note, no additional KVM enabling is required to allow the guest to use
EDECCSSA.  It's impossible to trap ENCLU (without completely preventing
the guest from using SGX).  Advertise EDECCSSA as supported purely so
that userspace doesn't need to special case EDECCSSA, i.e. doesn't need
to manually check host CPUID.

The inability to trap ENCLU also means that KVM can't prevent the guest
from using EDECCSSA, but that virtualization hole is benign as far as
KVM is concerned.  EDECCSSA is simply a fancy way to modify internal
enclave state.

More background about how do AEX-notify and EDECCSSA work:

SGX maintains a Current State Save Area Frame (CSSA) for each enclave
thread.  When AEX happens, the enclave thread context is saved to the
CSSA and the CSSA is increased by 1.  For a normal ERESUME which doesn't
deliver AEX notification, it restores the saved thread context from the
previously saved SSA and decreases the CSSA.  If AEX-notify is enabled
for one enclave, the ERESUME acts differently.  Instead of restoring the
saved thread context and decreasing the CSSA, it acts like EENTER which
doesn't decrease the CSSA but establishes a clean slate thread context
using the CSSA for the enclave to handle the notification.  After some
handling, the enclave must discard the "new-established" SSA and switch
back to the previously saved SSA (upon AEX).  Otherwise, the enclave
will run out of SSA space upon further AEXs and eventually fail to run.

To solve this problem, the new EDECCSSA essentially decreases the CSSA.
It can be used by the enclave notification handler to switch back to the
previous saved SSA when needed, i.e. after it handles the notification.

Signed-off-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Sean Christopherson <seanjc@google.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lore.kernel.org/all/20221101022422.858944-1-kai.huang%40intel.com
2022-11-04 15:33:56 -07:00
Sandipan Das
257449c6a5 x86/cpufeatures: Add LbrExtV2 feature bit
CPUID leaf 0x80000022 i.e. ExtPerfMonAndDbg advertises some new performance
monitoring features for AMD processors.

Bit 1 of EAX indicates support for Last Branch Record Extension Version 2
(LbrExtV2) features. If found to be set during PMU initialization, the EBX
bits of the same leaf can be used to determine the number of available LBR
entries.

For better utilization of feature words, LbrExtV2 is added as a scattered
feature bit.

[peterz: Rename to AMD_LBR_V2]
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/172d2b0df39306ed77221c45ee1aa62e8ae0548d.1660211399.git.sandipan.das@amd.com
2022-08-27 00:05:42 +02:00
Pawan Gupta
4ad3278df6 x86/speculation: Disable RRSBA behavior
Some Intel processors may use alternate predictors for RETs on
RSB-underflow. This condition may be vulnerable to Branch History
Injection (BHI) and intramode-BTI.

Kernel earlier added spectre_v2 mitigation modes (eIBRS+Retpolines,
eIBRS+LFENCE, Retpolines) which protect indirect CALLs and JMPs against
such attacks. However, on RSB-underflow, RET target prediction may
fallback to alternate predictors. As a result, RET's predicted target
may get influenced by branch history.

A new MSR_IA32_SPEC_CTRL bit (RRSBA_DIS_S) controls this fallback
behavior when in kernel mode. When set, RETs will not take predictions
from alternate predictors, hence mitigating RETs as well. Support for
this is enumerated by CPUID.7.2.EDX[RRSBA_CTRL] (bit2).

For spectre v2 mitigation, when a user selects a mitigation that
protects indirect CALLs and JMPs against BHI and intramode-BTI, set
RRSBA_DIS_S also to protect RETs for RSB-underflow case.

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-07-09 13:12:45 +02:00
Sandipan Das
d6d0c7f681 x86/cpufeatures: Add PerfMonV2 feature bit
CPUID leaf 0x80000022 i.e. ExtPerfMonAndDbg advertises some
new performance monitoring features for AMD processors.

Bit 0 of EAX indicates support for Performance Monitoring
Version 2 (PerfMonV2) features. If found to be set during
PMU initialization, the EBX bits of the same CPUID function
can be used to determine the number of available PMCs for
different PMU types. Additionally, Core PMCs can be managed
using new global control and status registers.

For better utilization of feature words, PerfMonV2 is added
as a scattered feature bit.

Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/c70e497e22f18e7f05b025bb64ca21cc12b17792.1650515382.git.sandipan.das@amd.com
2022-05-04 11:17:15 +02:00
Tony Luck
00a2f23eef x86/cpu: X86_FEATURE_INTEL_PPIN finally has a CPUID bit
After nine generations of adding to model specific list of CPUs that
support PPIN (Protected Processor Inventory Number) Intel allocated
a CPUID bit to enumerate the MSRs.

CPUID(EAX=7, ECX=1).EBX bit 0 enumerates presence of MSR_PPIN_CTL and
MSR_PPIN. Add it to the "scattered" CPUID bits and add an entry to the
ppin_cpuids[] x86_match_cpu() array to catch Intel CPUs that implement
it.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220131230111.2004669-3-tony.luck@intel.com
2022-02-01 16:15:19 +01:00
Sean Christopherson
b8921dccf3 x86/cpufeatures: Add SGX1 and SGX2 sub-features
Add SGX1 and SGX2 feature flags, via CPUID.0x12.0x0.EAX, as scattered
features, since adding a new leaf for only two bits would be wasteful.
As part of virtualizing SGX, KVM will expose the SGX CPUID leafs to its
guest, and to do so correctly needs to query hardware and kernel support
for SGX1 and SGX2.

Suppress both SGX1 and SGX2 from /proc/cpuinfo. SGX1 basically means
SGX, and for SGX2 there is no concrete use case of using it in
/proc/cpuinfo.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lkml.kernel.org/r/d787827dbfca6b3210ac3e432e3ac1202727e786.1616136308.git.kai.huang@intel.com
2021-03-25 17:33:11 +01:00
Sean Christopherson
fb35d30fe5 x86/cpufeatures: Assign dedicated feature word for CPUID_0x8000001F[EAX]
Collect the scattered SME/SEV related feature flags into a dedicated
word.  There are now five recognized features in CPUID.0x8000001F.EAX,
with at least one more on the horizon (SEV-SNP).  Using a dedicated word
allows KVM to use its automagic CPUID adjustment logic when reporting
the set of supported features to userspace.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Link: https://lkml.kernel.org/r/20210122204047.2860075-2-seanjc@google.com
2021-01-28 17:41:24 +01:00
Tom Lendacky
69372cf012 x86/cpu: Add VM page flush MSR availablility as a CPUID feature
On systems that do not have hardware enforced cache coherency between
encrypted and unencrypted mappings of the same physical page, the
hypervisor can use the VM page flush MSR (0xc001011e) to flush the cache
contents of an SEV guest page. When a small number of pages are being
flushed, this can be used in place of issuing a WBINVD across all CPUs.

CPUID 0x8000001f_eax[2] is used to determine if the VM page flush MSR is
available. Add a CPUID feature to indicate it is supported and define the
MSR.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <f1966379e31f9b208db5257509c4a089a87d33d0.1607620209.git.thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-12-14 11:09:30 -05:00
Linus Torvalds
da9803dfd3 This feature enhances the current guest memory encryption support
called SEV by also encrypting the guest register state, making the
 registers inaccessible to the hypervisor by en-/decrypting them on world
 switches. Thus, it adds additional protection to Linux guests against
 exfiltration, control flow and rollback attacks.
 
 With SEV-ES, the guest is in full control of what registers the
 hypervisor can access. This is provided by a guest-host exchange
 mechanism based on a new exception vector called VMM Communication
 Exception (#VC), a new instruction called VMGEXIT and a shared
 Guest-Host Communication Block which is a decrypted page shared between
 the guest and the hypervisor.
 
 Intercepts to the hypervisor become #VC exceptions in an SEV-ES guest so
 in order for that exception mechanism to work, the early x86 init code
 needed to be made able to handle exceptions, which, in itself, brings
 a bunch of very nice cleanups and improvements to the early boot code
 like an early page fault handler, allowing for on-demand building of the
 identity mapping. With that, !KASLR configurations do not use the EFI
 page table anymore but switch to a kernel-controlled one.
 
 The main part of this series adds the support for that new exchange
 mechanism. The goal has been to keep this as much as possibly
 separate from the core x86 code by concentrating the machinery in two
 SEV-ES-specific files:
 
  arch/x86/kernel/sev-es-shared.c
  arch/x86/kernel/sev-es.c
 
 Other interaction with core x86 code has been kept at minimum and behind
 static keys to minimize the performance impact on !SEV-ES setups.
 
 Work by Joerg Roedel and Thomas Lendacky and others.
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Merge tag 'x86_seves_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 SEV-ES support from Borislav Petkov:
 "SEV-ES enhances the current guest memory encryption support called SEV
  by also encrypting the guest register state, making the registers
  inaccessible to the hypervisor by en-/decrypting them on world
  switches. Thus, it adds additional protection to Linux guests against
  exfiltration, control flow and rollback attacks.

  With SEV-ES, the guest is in full control of what registers the
  hypervisor can access. This is provided by a guest-host exchange
  mechanism based on a new exception vector called VMM Communication
  Exception (#VC), a new instruction called VMGEXIT and a shared
  Guest-Host Communication Block which is a decrypted page shared
  between the guest and the hypervisor.

  Intercepts to the hypervisor become #VC exceptions in an SEV-ES guest
  so in order for that exception mechanism to work, the early x86 init
  code needed to be made able to handle exceptions, which, in itself,
  brings a bunch of very nice cleanups and improvements to the early
  boot code like an early page fault handler, allowing for on-demand
  building of the identity mapping. With that, !KASLR configurations do
  not use the EFI page table anymore but switch to a kernel-controlled
  one.

  The main part of this series adds the support for that new exchange
  mechanism. The goal has been to keep this as much as possibly separate
  from the core x86 code by concentrating the machinery in two
  SEV-ES-specific files:

    arch/x86/kernel/sev-es-shared.c
    arch/x86/kernel/sev-es.c

  Other interaction with core x86 code has been kept at minimum and
  behind static keys to minimize the performance impact on !SEV-ES
  setups.

  Work by Joerg Roedel and Thomas Lendacky and others"

* tag 'x86_seves_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (73 commits)
  x86/sev-es: Use GHCB accessor for setting the MMIO scratch buffer
  x86/sev-es: Check required CPU features for SEV-ES
  x86/efi: Add GHCB mappings when SEV-ES is active
  x86/sev-es: Handle NMI State
  x86/sev-es: Support CPU offline/online
  x86/head/64: Don't call verify_cpu() on starting APs
  x86/smpboot: Load TSS and getcpu GDT entry before loading IDT
  x86/realmode: Setup AP jump table
  x86/realmode: Add SEV-ES specific trampoline entry point
  x86/vmware: Add VMware-specific handling for VMMCALL under SEV-ES
  x86/kvm: Add KVM-specific VMMCALL handling under SEV-ES
  x86/paravirt: Allow hypervisor-specific VMMCALL handling under SEV-ES
  x86/sev-es: Handle #DB Events
  x86/sev-es: Handle #AC Events
  x86/sev-es: Handle VMMCALL Events
  x86/sev-es: Handle MWAIT/MWAITX Events
  x86/sev-es: Handle MONITOR/MONITORX Events
  x86/sev-es: Handle INVD Events
  x86/sev-es: Handle RDPMC Events
  x86/sev-es: Handle RDTSC(P) Events
  ...
2020-10-14 10:21:34 -07:00
Linus Torvalds
64743e652c * Misc cleanups to the resctrl code in preparation for the ARM side, by
James Morse.
 
 * Add support for controlling per-thread memory bandwidth throttling
 delay values on hw which supports it, by Fenghua Yu.
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Merge tag 'x86_cache_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 cache resource control updates from Borislav Petkov:

 - Misc cleanups to the resctrl code in preparation for the ARM side
   (James Morse)

 - Add support for controlling per-thread memory bandwidth throttling
   delay values on hw which supports it (Fenghua Yu)

* tag 'x86_cache_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/resctrl: Enable user to view thread or core throttling mode
  x86/resctrl: Enumerate per-thread MBA controls
  cacheinfo: Move resctrl's get_cache_id() to the cacheinfo header file
  x86/resctrl: Add struct rdt_cache::arch_has_{sparse, empty}_bitmaps
  x86/resctrl: Merge AMD/Intel parse_bw() calls
  x86/resctrl: Add struct rdt_membw::arch_needs_linear to explain AMD/Intel MBA difference
  x86/resctrl: Use is_closid_match() in more places
  x86/resctrl: Include pid.h
  x86/resctrl: Use container_of() in delayed_work handlers
  x86/resctrl: Fix stale comment
  x86/resctrl: Remove struct rdt_membw::max_delay
  x86/resctrl: Remove unused struct mbm_state::chunks_bw
2020-10-12 10:53:32 -07:00
Krish Sadhukhan
5866e9205b x86/cpu: Add hardware-enforced cache coherency as a CPUID feature
In some hardware implementations, coherency between the encrypted and
unencrypted mappings of the same physical page is enforced. In such a system,
it is not required for software to flush the page from all CPU caches in the
system prior to changing the value of the C-bit for a page. This hardware-
enforced cache coherency is indicated by EAX[10] in CPUID leaf 0x8000001f.

 [ bp: Use one of the free slots in word 3. ]

Suggested-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200917212038.5090-2-krish.sadhukhan@oracle.com
2020-09-18 10:46:41 +02:00
Tom Lendacky
360e7c5c4c x86/cpufeatures: Add SEV-ES CPU feature
Add CPU feature detection for Secure Encrypted Virtualization with
Encrypted State. This feature enhances SEV by also encrypting the
guest register state, making it in-accessible to the hypervisor.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-6-joro@8bytes.org
2020-09-07 19:45:24 +02:00
Fenghua Yu
e48cb1a3fb x86/resctrl: Enumerate per-thread MBA controls
Some systems support per-thread Memory Bandwidth Allocation (MBA) which
applies a throttling delay value to each hardware thread instead of to
a core. Per-thread MBA is enumerated by CPUID.

No feature flag is shown in /proc/cpuinfo. User applications need to
check a resctrl throttling mode info file to know if the feature is
supported.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/1598296281-127595-2-git-send-email-fenghua.yu@intel.com
2020-08-26 17:46:12 +02:00
Ingo Molnar
eb243d1d28 x86/mm/pat: Rename <asm/pat.h> => <asm/memtype.h>
pat.h is a file whose main purpose is to provide the memtype_*() APIs.

PAT is the low level hardware mechanism - but the high level abstraction
is memtype.

So name the header <memtype.h> as well - this goes hand in hand with memtype.c
and memtype_interval.c.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-10 10:12:55 +01:00
Fenghua Yu
acec0ce081 x86/cpufeatures: Combine word 11 and 12 into a new scattered features word
It's a waste for the four X86_FEATURE_CQM_* feature bits to occupy two
whole feature bits words. To better utilize feature words, re-define
word 11 to host scattered features and move the four X86_FEATURE_CQM_*
features into Linux defined word 11. More scattered features can be
added in word 11 in the future.

Rename leaf 11 in cpuid_leafs to CPUID_LNX_4 to reflect it's a
Linux-defined leaf.

Rename leaf 12 as CPUID_DUMMY which will be replaced by a meaningful
name in the next patch when CPUID.7.1:EAX occupies world 12.

Maximum number of RMID and cache occupancy scale are retrieved from
CPUID.0xf.1 after scattered CQM features are enumerated. Carve out the
code into a separate function.

KVM doesn't support resctrl now. So it's safe to move the
X86_FEATURE_CQM_* features to scattered features word 11 for KVM.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Aaron Lewis <aaronlewis@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Babu Moger <babu.moger@amd.com>
Cc: "Chang S. Bae" <chang.seok.bae@intel.com>
Cc: "Sean J Christopherson" <sean.j.christopherson@intel.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: kvm ML <kvm@vger.kernel.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Peter Feiner <pfeiner@google.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Ravi V Shankar <ravi.v.shankar@intel.com>
Cc: Sherry Hurwitz <sherry.hurwitz@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Lendacky <Thomas.Lendacky@amd.com>
Cc: x86 <x86@kernel.org>
Link: https://lkml.kernel.org/r/1560794416-217638-2-git-send-email-fenghua.yu@intel.com
2019-06-20 12:38:44 +02:00
Linus Torvalds
db2ab474c4 Merge branch 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cpu updates from Ingo Molnar:
 "Misc changes:

   - Fix nr_cpus= boot option interaction bug with logical package
     management

   - Clean up UMIP detection messages

   - Add WBNOINVD instruction detection

   - Remove the unused get_scattered_cpuid_leaf() function"

* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/topology: Use total_cpus for max logical packages calculation
  x86/umip: Make the UMIP activated message generic
  x86/umip: Print UMIP line only once
  x86/cpufeatures: Add WBNOINVD feature definition
  x86/cpufeatures: Remove get_scattered_cpuid_leaf()
2018-12-26 17:35:41 -08:00
Linus Torvalds
312a466155 Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cleanups from Ingo Molnar:
 "Misc cleanups"

* 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/kprobes: Remove trampoline_handler() prototype
  x86/kernel: Fix more -Wmissing-prototypes warnings
  x86: Fix various typos in comments
  x86/headers: Fix -Wmissing-prototypes warning
  x86/process: Avoid unnecessary NULL check in get_wchan()
  x86/traps: Complete prototype declarations
  x86/mce: Fix -Wmissing-prototypes warnings
  x86/gart: Rewrite early_gart_iommu_check() comment
2018-12-26 17:03:51 -08:00
Borislav Petkov
ad3bc25a32 x86/kernel: Fix more -Wmissing-prototypes warnings
... with the goal of eventually enabling -Wmissing-prototypes by
default. At least on x86.

Make functions static where possible, otherwise add prototypes or make
them visible through includes.

asm/trace/ changes courtesy of Steven Rostedt <rostedt@goodmis.org>.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> # ACPI + cpufreq bits
Cc: Andrew Banman <andrew.banman@hpe.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mike Travis <mike.travis@hpe.com>
Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yi Wang <wang.yi59@zte.com.cn>
Cc: linux-acpi@vger.kernel.org
2018-12-08 12:24:35 +01:00
Sherry Hurwitz
9f72f855a6 x86/resctrl: Add AMD's X86_FEATURE_MBA to the scattered CPUID features
The feature bit X86_FEATURE_MBA is detected via CPUID leaf 0x80000008
EBX Bit 06. This bit indicates the support of AMD's MBA feature.

This feature is supported by both Intel and AMD. But they are detected
in different CPUID leaves.

 [ bp: s/cpuid/CPUID/g ]

Signed-off-by: Sherry Hurwitz <sherry.hurwitz@amd.com>
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: "Chang S. Bae" <chang.seok.bae@intel.com>
Cc: David Miller <davem@davemloft.net>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Dmitry Safonov <dima@arista.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: <linux-doc@vger.kernel.org>
Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Pu Wen <puwen@hygon.cn>
Cc: <qianyue.zj@alibaba-inc.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Reinette Chatre <reinette.chatre@intel.com>
Cc: Rian Hunter <rian@alum.mit.edu>
Cc: Sherry Hurwitz <sherry.hurwitz@amd.com>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Lendacky <Thomas.Lendacky@amd.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: <xiaochen.shen@intel.com>
Link: https://lkml.kernel.org/r/20181121202811.4492-10-babu.moger@amd.com
2018-11-22 20:16:19 +01:00
Sean Christopherson
43500e6f29 x86/cpufeatures: Remove get_scattered_cpuid_leaf()
get_scattered_cpuid_leaf() was added[1] to help KVM rebuild hardware-
defined leafs that are rearranged by Linux to avoid bloating the
x86_capability array. Eventually, the last consumer of the function was
removed[2], but the function itself was kept, perhaps even intentionally
as a form of documentation.

Remove get_scattered_cpuid_leaf() as it is currently not used by KVM.
Furthermore, simply rebuilding the "real" leaf does not resolve all of
KVM's woes when it comes to exposing a scattered CPUID feature, i.e.
keeping the function as documentation may be counter-productive in some
scenarios, e.g. when KVM needs to do more than simply expose the leaf.

[1] 47bdf3378d ("x86/cpuid: Provide get_scattered_cpuid_leaf()")
[2] b7b27aa011 ("KVM/x86: Update the reverse_cpuid list to include CPUID_7_EDX")

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Ingo Molnar <mingo@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: x86-ml <x86@kernel.org>
Link: http://lkml.kernel.org/r/20181105185725.18679-1-sean.j.christopherson@intel.com
2018-11-05 20:54:20 +01:00
Radim Krčmář
7bf14c28ee Merge branch 'x86/hyperv' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Topic branch for stable KVM clockource under Hyper-V.

Thanks to Christoffer Dall for resolving the ARM conflict.
2018-02-01 15:04:17 +01:00
Linus Torvalds
6304672b7f Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/pti updates from Thomas Gleixner:
 "Another set of melted spectrum related changes:

   - Code simplifications and cleanups for RSB and retpolines.

   - Make the indirect calls in KVM speculation safe.

   - Whitelist CPUs which are known not to speculate from Meltdown and
     prepare for the new CPUID flag which tells the kernel that a CPU is
     not affected.

   - A less rigorous variant of the module retpoline check which merily
     warns when a non-retpoline protected module is loaded and reflects
     that fact in the sysfs file.

   - Prepare for Indirect Branch Prediction Barrier support.

   - Prepare for exposure of the Speculation Control MSRs to guests, so
     guest OSes which depend on those "features" can use them. Includes
     a blacklist of the broken microcodes. The actual exposure of the
     MSRs through KVM is still being worked on"

* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/speculation: Simplify indirect_branch_prediction_barrier()
  x86/retpoline: Simplify vmexit_fill_RSB()
  x86/cpufeatures: Clean up Spectre v2 related CPUID flags
  x86/cpu/bugs: Make retpoline module warning conditional
  x86/bugs: Drop one "mitigation" from dmesg
  x86/nospec: Fix header guards names
  x86/alternative: Print unadorned pointers
  x86/speculation: Add basic IBPB (Indirect Branch Prediction Barrier) support
  x86/cpufeature: Blacklist SPEC_CTRL/PRED_CMD on early Spectre v2 microcodes
  x86/pti: Do not enable PTI on CPUs which are not vulnerable to Meltdown
  x86/msr: Add definitions for new speculation control MSRs
  x86/cpufeatures: Add AMD feature bits for Speculation Control
  x86/cpufeatures: Add Intel feature bits for Speculation Control
  x86/cpufeatures: Add CPUID_7_EDX CPUID leaf
  module/retpoline: Warn about missing retpoline in module
  KVM: VMX: Make indirect call speculation safe
  KVM: x86: Make indirect calls in emulator speculation safe
2018-01-29 19:08:02 -08:00
David Woodhouse
95ca0ee863 x86/cpufeatures: Add CPUID_7_EDX CPUID leaf
This is a pure feature bits leaf. There are two AVX512 feature bits in it
already which were handled as scattered bits, and three more from this leaf
are going to be added for speculation control features.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: gnomes@lxorguk.ukuu.org.uk
Cc: ak@linux.intel.com
Cc: ashok.raj@intel.com
Cc: dave.hansen@intel.com
Cc: karahmed@amazon.de
Cc: arjan@linux.intel.com
Cc: torvalds@linux-foundation.org
Cc: peterz@infradead.org
Cc: bp@alien8.de
Cc: pbonzini@redhat.com
Cc: tim.c.chen@linux.intel.com
Cc: gregkh@linux-foundation.org
Link: https://lkml.kernel.org/r/1516896855-7642-2-git-send-email-dwmw@amazon.co.uk
2018-01-26 15:53:16 +01:00
Fenghua Yu
a511e79353 x86/intel_rdt: Enumerate L2 Code and Data Prioritization (CDP) feature
L2 Code and Data Prioritization (CDP) is enumerated in
CPUID(EAX=0x10, ECX=0x2):ECX.bit2

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: Vikas" <vikas.shivappa@intel.com>
Cc: Sai Praneeth" <sai.praneeth.prakhya@intel.com>
Cc: Reinette" <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/1513810644-78015-4-git-send-email-fenghua.yu@intel.com
2018-01-18 09:33:30 +01:00
Paolo Bonzini
4fdec2034b x86/cpufeature: Move processor tracing out of scattered features
Processor tracing is already enumerated in word 9 (CPUID[7,0].EBX),
so do not duplicate it in the scattered features word.

Besides being more tidy, this will be useful for KVM when it presents
processor tracing to the guests.  KVM selects host features that are
supported by both the host kernel (depending on command line options,
CPU errata, or whatever) and KVM.  Whenever a full feature word exists,
KVM's code is written in the expectation that the CPUID bit number
matches the X86_FEATURE_* bit number, but this is not the case for
X86_FEATURE_INTEL_PT.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luwei Kang <luwei.kang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm@vger.kernel.org
Link: http://lkml.kernel.org/r/1516117345-34561-1-git-send-email-pbonzini@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-01-17 07:38:39 +01:00
Tom Lendacky
18c71ce9c8 x86/CPU/AMD: Add the Secure Encrypted Virtualization CPU feature
Update the CPU features to include identifying and reporting on the
Secure Encrypted Virtualization (SEV) feature.  SEV is identified by
CPUID 0x8000001f, but requires BIOS support to enable it (set bit 23 of
MSR_K8_SYSCFG and set bit 0 of MSR_K7_HWCR).  Only show the SEV feature
as available if reported by CPUID and enabled by BIOS.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: kvm@vger.kernel.org
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
2017-12-04 10:57:23 -06:00