Commit Graph

320 Commits

Author SHA1 Message Date
Linus Torvalds
5e6ff28676 hyperv-next for v7.3-rc1
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Merge tag 'hyperv-next-signed-20260826' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull hyperv updates from Wei Liu:

 - Decrypt netvsc buffer on contiguous direct-map addresses (Kameron
   Carr)

 - Drop WS2012/2012R2 & Win8/8.1 Hyper-V support (Michael Kelley)

 - Use more meaningful errnos for hypercall status code (Hardik Garg)

 - Fix lost interrupts on CPU hot-unplug for Hyper-V PCI/MSI (Naman
   Jain)

 - Reserve more MSHV vectors for Linux root partition (Wei Liu)

* tag 'hyperv-next-signed-20260826' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  clocksource: hyper-v: Remove support for stimer interrupts in message mode
  scsi: storvsc: Remove support for storvsc protocol of old Hyper-V hosts
  hv_netvsc: Remove GPADL teardown special case for old Hyper-V hosts
  hv_sock: Remove check for old Hyper-V hosts
  Drivers: hv: Remove support for WS2012/2012R2 & Win8/8.1 version of Hyper-V
  hv_netvsc: Allocate send/receive buffers using vmbus_alloc_buffer()
  Drivers: hv: vmbus: Add vmbus_alloc_buffer()/vmbus_free_buffer() for CoCo VMs
  Drivers: hv: vmbus: add vmbus_establish_gpadl_caller_decrypted()
  Drivers: hv: vmbus: Skip VMBus module cleanup for non-nested root partition
  x86/hyperv: reserve more vectors
  PCI: hv: Set irq_retrigger callback for the Hyper-V PCI MSI irqchip
  Drivers: hv: Use meaningful errnos for hypercall status codes
2026-08-26 16:47:40 -07:00
Michael Kelley
be0cfab740 clocksource: hyper-v: Remove support for stimer interrupts in message mode
In Hyper-V versions prior to WS2016/Win10, Hyper-V synthetic timers
interrupt the guest by delivering a message that is initially handled
by the Linux VMBus driver. Starting with WS2016/Win10, Hyper-V can
deliver stimer interrupts directly to an assigned interrupt vector
without involving the VMBus driver. This is called "Direct Mode".

With the overall removal of Linux support for running on Hyper-V
hosts earlier than WS2016 and Windows 10, it's no longer necessary
to support the legacy message-based delivery. Remove that delivery
mechanism and always use Direct Mode. If for some reason, the
Hyper-V host does not enumerate Direct Mode, output an error
message but continue to run using the LAPIC timer instead of an
stimer.

With these changes, the VMBus driver no longer calls the stimer
interrupt service routine. This removal has a broader benefit in
unblocking the disentangling of VMBus code and stimer code, as
they should be independent of each other. The final disentangling
will come as a follow-on patch set.

Signed-off-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-08-24 00:36:14 +00:00
Linus Torvalds
8dcef8882a x86/msr updates for v7.3:
- Streamline the x86 MSR handling APIs along the 64-bit
    variants, simplifying the interfaces. Removal of the
    old APIs is planned for the next cycle, to reduce
    churn & integration pain. (Juergen Gross)
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-msr-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 MSR updates from Ingo Molnar:

 - Streamline the x86 MSR handling APIs along the 64-bit variants,
   simplifying the interfaces.

   Removal of the old APIs is planned for the next cycle, to reduce
   churn & integration pain (Juergen Gross)

* tag 'x86-msr-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits)
  x86/mce: Work around build warning after MSR-interface switch
  cpufreq: Stop using 32-bit MSR interfaces
  x86/featctl: Stop using 32-bit MSR interfaces
  KVM/x86: Stop using 32-bit MSR interfaces
  x86/mtrr: Stop using 32-bit MSR interfaces
  acpi: Stop using 32-bit MSR interfaces
  powercap: Stop using 32-bit MSR interfaces
  thermal/intel: Stop using 32-bit MSR interfaces
  x86/olpc: Stop using 32-bit MSR interfaces
  x86/hyperv: Stop using 32-bit MSR interfaces
  hwmon: Stop using 32-bit MSR interfaces
  EDAC: Stop using 32-bit MSR interfaces
  x86/cpu: Stop using 32-bit MSR interfaces
  x86/apic: Stop using 32-bit MSR interfaces
  x86/resctrl: Stop using 32-bit MSR interfaces
  x86/tsc: Stop using 32-bit MSR interfaces
  x86/amd: Stop using 32-bit MSR interfaces
  x86/pci: Stop using 32-bit MSR interfaces
  x86/hygon: Stop using 32-bit MSR interfaces
  x86/mce: Stop using 32-bit MSR interfaces
  ...
2026-08-18 14:02:15 -07:00
Peter Zijlstra
fc6ad5eadc x86/paravirt: Use static_call() for the paravirt spinlock ops
queued_spin_lock_slowpath() and queued_spin_unlock() are dispatched
through pv_ops_lock via the paravirt-ops ALTERNATIVE machinery, which
picks the target (native inline store / hypervisor call) once at boot
and cannot change at runtime.

Convert both to static_call(). The site becomes a direct call patched in
place (one byte smaller), and on native the unlock still collapses to
the inline "movb $0, (%rdi)" store, so the fast path is unchanged.

Unlike the ALTERNATIVE mechanism, a static_call() target can also be
updated at runtime via static_call_update(). This is a prerequisite for
the contended_release tracepoint, which has to swap in a traced unlock
while the system is running.

[ ilvokhin: commit message; fix PARAVIRT_SPINLOCKS=n build; teach
  __static_call_validate() about the inline unlock insn; make the
  slowpath site module-safe: static_call_mod() +
  EXPORT_STATIC_CALL_TRAMP(); pass @lock to the callee-save unlock,
  fixing a boot hang under CALL_DEPTH_TRACKING. Boot tested native + KVM
  PV guest. ]

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Co-developed-by: Dmitry Ilvokhin <d@ilvokhin.com>
Signed-off-by: Dmitry Ilvokhin <d@ilvokhin.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/all/20260603120811.GW3493090@noisy.programming.kicks-ass.net/
Link: https://patch.msgid.link/9a32ae399eb804a02a31af04dcabe7e7ee4f3fdf.1785778551.git.d@ilvokhin.com
2026-08-07 17:58:09 +02:00
Juergen Gross
f1b5991064 x86/hyperv: Stop using 32-bit MSR interfaces
The 32-bit MSR interface rdmsr() is planned to be removed. Use the
related 64-bit variant instead.

This conversion also simplifies the code a bit.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Long Li <longli@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Link: https://patch.msgid.link/20260629060526.3638272-28-jgross@suse.com
2026-07-03 11:33:59 +02:00
Linus Torvalds
6e869de3a1 hyperv-next for v7.2-rc1
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Merge tag 'hyperv-next-signed-20260621' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull hyperv updates from Wei Liu:

 - Use wakeup mailbox to boot APs in Hyper-V VTL2 TDX guests (Yunhong
   Jiang, Ricardo Neri)

 - Move the Hyper-V IOMMU to its own subdirectory (Mukesh Rathor)

 - Cosmetic changes to mshv and balloon driver (Junrui Luo, Markus
   Elfring)

* tag 'hyperv-next-signed-20260621' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  mshv: add bounds check on vp_index in mshv_intercept_isr()
  hv_balloon: Simplify data output in hv_balloon_debug_show()
  x86/hyperv: Cosmetic changes in irqdomain.c for readability
  iommu/hyperv: Create hyperv subdirectory under drivers/iommu
  x86/hyperv/vtl: Use the wakeup mailbox to boot secondary CPUs
  x86/hyperv/vtl: Mark the wakeup mailbox page as private
  x86/acpi: Add a helper to get the address of the wakeup mailbox
  x86/hyperv/vtl: Setup the 64-bit trampoline for TDX guests
  x86/realmode: Make the location of the trampoline configurable
  x86/hyperv/vtl: Set real_mode_header in hv_vtl_init_platform()
  x86/dt: Parse the Wakeup Mailbox for Intel processors
  dt-bindings: reserved-memory: Wakeup Mailbox for Intel processors
  x86/acpi: Add functions to setup and access the wakeup mailbox
  x86/topology: Add missing struct declaration and attribute dependency
2026-06-22 08:06:13 -07:00
Mukesh R
982cb55bec x86/hyperv: Cosmetic changes in irqdomain.c for readability
Make cosmetic changes:
 o Rename struct pci_dev *dev to *pdev since there are cases of
   struct device *dev in the file and all over the kernel
 o Rename hv_build_pci_dev_id to hv_build_devid_type_pci in anticipation
   of building different types of device ids
 o Fix checkpatch.pl issues with return and extraneous printk
 o Replace spaces with tabs
 o Rename struct hv_devid *xxx to struct hv_devid *hv_devid given code
   paths involve many types of device ids
 o Fix indentation in a large if block by using goto.

There are no functional changes.

Reviewed-by: Souradeep Chakrabarti <schakrabarti@linux.microsoft.com>
Reviewed-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
Signed-off-by: Mukesh R <mrathor@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-06-07 22:59:49 -07:00
Ricardo Neri
7a035678fc x86/hyperv/vtl: Use the wakeup mailbox to boot secondary CPUs
The hypervisor is an untrusted entity for TDX guests. It cannot be used
to boot secondary CPUs. The function hv_vtl_wakeup_secondary_cpu() cannot
be used.

Instead, the virtual firmware boots the secondary CPUs and places them in
a state to transfer control to the kernel using the wakeup mailbox. The
firmware enumerates the mailbox via either an ACPI table or a DeviceTree
node.

If the wakeup mailbox is present, the kernel updates the APIC callback
wakeup_secondary_cpu_64() to use it.

Reviewed-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Dexuan Cui <dexuan@kernel.org>
2026-05-28 20:01:26 +00:00
Yunhong Jiang
8020034119 x86/hyperv/vtl: Mark the wakeup mailbox page as private
The current code maps MMIO devices as shared (decrypted) by default in a
confidential computing VM.

In a TDX environment, secondary CPUs are booted using the Multiprocessor
Wakeup Structure defined in the ACPI specification. The virtual firmware
and the operating system function in the guest context, without
intervention from the VMM. Map the physical memory of the mailbox as
private. Use the is_private_mmio() callback.

Signed-off-by: Yunhong Jiang <yunhong.jiang@linux.intel.com>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Dexuan Cui <dexuan@kernel.org>
2026-05-28 20:01:26 +00:00
Yunhong Jiang
aa7719039b x86/hyperv/vtl: Setup the 64-bit trampoline for TDX guests
The hypervisor is an untrusted entity for TDX guests. It cannot be used
to boot secondary CPUs - neither via hypercalls nor the INIT assert,
de-assert, plus Start-Up IPI messages.

Instead, the platform virtual firmware boots the secondary CPUs and
puts them in a state to transfer control to the kernel. This mechanism uses
the wakeup mailbox described in the Multiprocessor Wakeup Structure of the
ACPI specification. The entry point to the kernel is trampoline_start64.

Allocate and setup the trampoline using the default x86_platform callbacks.

The platform firmware configures the secondary CPUs in long mode. It is no
longer necessary to locate the trampoline under 1MB memory. After handoff
from firmware, the trampoline code switches briefly to 32-bit addressing
mode, which has an addressing limit of 4GB. Set the upper bound of the
trampoline memory accordingly.

Reviewed-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Yunhong Jiang <yunhong.jiang@linux.intel.com>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Dexuan Cui <dexuan@kernel.org>
2026-05-28 20:01:25 +00:00
Yunhong Jiang
7e4c083ece x86/hyperv/vtl: Set real_mode_header in hv_vtl_init_platform()
Hyper-V VTL clears x86_platform.realmode_{init(), reserve()} in
hv_vtl_init_platform() whereas it sets real_mode_header later in
hv_vtl_early_init(). There is no need to deal with the settings of real
mode memory in two places. Also, both functions are called much earlier
than x86_platform.realmode_init() (via an early_initcall), where the
real_mode_header is needed.

Set real_mode_header in hv_vtl_init_platform() to keep all code dealing
with memory for the real mode trampoline in one place. Besides making the
code more readable, it prepares it for a subsequent changeset in which the
behavior needs to change to support Hyper-V VTL guests in a TDX
environment.

Reviewed-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Yunhong Jiang <yunhong.jiang@linux.intel.com>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Dexuan Cui <dexuan@kernel.org>
2026-05-28 20:01:25 +00:00
Thomas Gleixner
2b57c69917 x86/irq: Make irqstats array based
Having the x86 specific interrupt statistics as a data structure with
individual members instead of an array is just stupid as it requires
endless copy and paste in arch_show_interrupts() and arch_irq_stat_cpu(),
where the latter does not even take the latest interrupt additions into
account. The resulting #ifdef orgy is just disgusting.

Convert it to an array of counters, which does not make a difference in the
actual interrupt hotpath increment as the array index is constant and
therefore not any different than the member based access.

But in arch_show_interrupts() and arch_irq_stat_cpu() this just turns into
a loop, which reduces the text size by ~2k (~12%):

   text	   data	    bss	    dec	    hex	filename
  19643	  15250	    904	  35797	   8bd5	../build/arch/x86/kernel/irq.o
  17355	  15250	    904	  33509	   82e5	../build/arch/x86/kernel/irq.o

Adding a new vector or software counter only requires to update the table
and everything just works. Using the core provided emit function which
speeds up 0 outputs makes it significantly faster.

Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Radu Rendec <radu@rendec.net>
Link: https://patch.msgid.link/20260517194931.196070643@kernel.org
2026-05-26 16:21:12 +02:00
Uros Bizjak
afeb96cb18 x86/hyperv: Use any general-purpose register when saving %cr2 and %cr8
hv_hvcrash_ctxt_save() in arch/x86/hyperv/hv_crash.c currently saves %cr2
and %cr8 using %eax ("=a"). This unnecessarily forces a specific register.
Update the inline assembly to use a general-purpose register ("=r") for
both %cr2 and %cr8. This makes the code more flexible for the compiler
while producing the same saved context contents.

No functional changes.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Long Li <longli@microsoft.com>
Cc: Thomas Gleixner <tglx@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-03-12 04:25:20 +00:00
Uros Bizjak
2536091d58 x86/hyperv: Use current_stack_pointer to avoid asm() in hv_hvcrash_ctxt_save()
Use current_stack_pointer to avoid asm() when saving %rsp to the
crash context memory in hv_hvcrash_ctxt_save(). The new code is
more readable and results in exactly the same object file.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Long Li <longli@microsoft.com>
Cc: Thomas Gleixner <tglx@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-03-12 04:25:19 +00:00
Uros Bizjak
3484127c19 x86/hyperv: Save segment registers directly to memory in hv_hvcrash_ctxt_save()
hv_hvcrash_ctxt_save() in arch/x86/hyperv/hv_crash.c currently saves
segment registers via a general-purpose register (%eax). Update the
code to save segment registers (cs, ss, ds, es, fs, gs) directly to
the crash context memory using movw. This avoids unnecessary use of
a general-purpose register, making the code simpler and more efficient.

The size of the corresponding object file improves as follows:

   text    data     bss     dec     hex filename
   4167     176     200    4543    11bf hv_crash-old.o
   4151     176     200    4527    11af hv_crash-new.o

No functional change occurs to the saved context contents; this is
purely a code-quality improvement.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Long Li <longli@microsoft.com>
Cc: Thomas Gleixner <tglx@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-03-12 04:25:19 +00:00
Ard Biesheuvel
3fde5281b8 x86/hyperv: Use __naked attribute to fix stackless C function
hv_crash_c_entry() is a C function that is entered without a stack,
and this is only allowed for functions that have the __naked attribute,
which informs the compiler that it must not emit the usual prologue and
epilogue or emit any other kind of instrumentation that relies on a
stack frame.

So split up the function, and set the __naked attribute on the initial
part that sets up the stack, GDT, IDT and other pieces that are needed
for ordinary C execution. Given that function calls are not permitted
either, use the existing long return coded in an asm() block to call the
second part of the function, which is an ordinary function that is
permitted to call other functions as usual.

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com> # asm parts, not hv parts
Reviewed-by: Mukesh Rathor <mrathor@linux.microsoft.com>
Acked-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: linux-hyperv@vger.kernel.org
Fixes: 94212d3461 ("x86/hyperv: Implement hypervisor RAM collection into vmcore")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-03-11 16:54:24 +00:00
Linus Torvalds
32a92f8c89 Convert more 'alloc_obj' cases to default GFP_KERNEL arguments
This converts some of the visually simpler cases that have been split
over multiple lines.  I only did the ones that are easy to verify the
resulting diff by having just that final GFP_KERNEL argument on the next
line.

Somebody should probably do a proper coccinelle script for this, but for
me the trivial script actually resulted in an assertion failure in the
middle of the script.  I probably had made it a bit _too_ trivial.

So after fighting that far a while I decided to just do some of the
syntactically simpler cases with variations of the previous 'sed'
scripts.

The more syntactically complex multi-line cases would mostly really want
whitespace cleanup anyway.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21 20:03:00 -08:00
Linus Torvalds
bf4afc53b7 Convert 'alloc_obj' family to use the new default GFP_KERNEL argument
This was done entirely with mindless brute force, using

    git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21 17:09:51 -08:00
Kees Cook
69050f8d6d treewide: Replace kmalloc with kmalloc_obj for non-scalar types
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook <kees@kernel.org>
2026-02-21 01:02:28 -08:00
Linus Torvalds
d31558c077 hyperv-next for v7.0
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Merge tag 'hyperv-next-signed-20260218' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull Hyper-V updates from Wei Liu:

 - Debugfs support for MSHV statistics (Nuno Das Neves)

 - Support for the integrated scheduler (Stanislav Kinsburskii)

 - Various fixes for MSHV memory management and hypervisor status
   handling (Stanislav Kinsburskii)

 - Expose more capabilities and flags for MSHV partition management
   (Anatol Belski, Muminul Islam, Magnus Kulke)

 - Miscellaneous fixes to improve code quality and stability (Carlos
   López, Ethan Nelson-Moore, Li RongQing, Michael Kelley, Mukesh
   Rathor, Purna Pavan Chandra Aekkaladevi, Stanislav Kinsburskii, Uros
   Bizjak)

 - PREEMPT_RT fixes for vmbus interrupts (Jan Kiszka)

* tag 'hyperv-next-signed-20260218' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (34 commits)
  mshv: Handle insufficient root memory hypervisor statuses
  mshv: Handle insufficient contiguous memory hypervisor status
  mshv: Introduce hv_deposit_memory helper functions
  mshv: Introduce hv_result_needs_memory() helper function
  mshv: Add SMT_ENABLED_GUEST partition creation flag
  mshv: Add nested virtualization creation flag
  Drivers: hv: vmbus: Simplify allocation of vmbus_evt
  mshv: expose the scrub partition hypercall
  mshv: Add support for integrated scheduler
  mshv: Use try_cmpxchg() instead of cmpxchg()
  x86/hyperv: Fix error pointer dereference
  x86/hyperv: Reserve 3 interrupt vectors used exclusively by MSHV
  Drivers: hv: vmbus: Use kthread for vmbus interrupts on PREEMPT_RT
  x86/hyperv: Remove ASM_CALL_CONSTRAINT with VMMCALL insn
  x86/hyperv: Use savesegment() instead of inline asm() to save segment registers
  mshv: fix SRCU protection in irqfd resampler ack handler
  mshv: make field names descriptive in a header struct
  x86/hyperv: Update comment in hyperv_cleanup()
  mshv: clear eventfd counter on irqfd shutdown
  x86/hyperv: Use memremap()/memunmap() instead of ioremap_cache()/iounmap()
  ...
2026-02-20 08:48:31 -08:00
Ethan Tidmore
705d01c8d7 x86/hyperv: Fix error pointer dereference
The function idle_thread_get() can return an error pointer and is not
checked for it. Add check for error pointer.

Detected by Smatch:
arch/x86/hyperv/hv_vtl.c:126 hv_vtl_bringup_vcpu() error:
'idle' dereferencing possible ERR_PTR()

Fixes: 2b4b90e053 ("x86/hyperv: Use per cpu initial stack for vtl context")
Signed-off-by: Ethan Tidmore <ethantidmore06@gmail.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-02-18 23:22:27 +00:00
Uros Bizjak
885e78d71f x86/hyperv: Remove ASM_CALL_CONSTRAINT with VMMCALL insn
Unlike CALL instruction, VMMCALL does not push to the stack, so it's
OK to allow the compiler to insert it before the frame pointer gets
set up by the containing function. ASM_CALL_CONSTRAINT is for CALLs
that must be inserted after the frame pointer is set up, so it is
over-constraining here and can be removed.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-02-18 06:42:57 +00:00
Uros Bizjak
834ef6aa09 x86/hyperv: Use savesegment() instead of inline asm() to save segment registers
Use standard savesegment() utility macro to save segment registers.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Acked-by: Wei Liu <wei.liu@kernel.org>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-02-18 06:42:57 +00:00
Linus Torvalds
57cb845067 - A nice cleanup to the paravirt code containing a unification of the paravirt
clock interface, taming the include hell by splitting the pv_ops structure
   and removing of a bunch of obsolete code. Work by Juergen Gross.
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Merge tag 'x86_paravirt_for_v7.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 paravirt updates from Borislav Petkov:

 - A nice cleanup to the paravirt code containing a unification of the
   paravirt clock interface, taming the include hell by splitting the
   pv_ops structure and removing of a bunch of obsolete code (Juergen
   Gross)

* tag 'x86_paravirt_for_v7.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  x86/paravirt: Use XOR r32,r32 to clear register in pv_vcpu_is_preempted()
  x86/paravirt: Remove trailing semicolons from alternative asm templates
  x86/pvlocks: Move paravirt spinlock functions into own header
  x86/paravirt: Specify pv_ops array in paravirt macros
  x86/paravirt: Allow pv-calls outside paravirt.h
  objtool: Allow multiple pv_ops arrays
  x86/xen: Drop xen_mmu_ops
  x86/xen: Drop xen_cpu_ops
  x86/xen: Drop xen_irq_ops
  x86/paravirt: Move pv_native_*() prototypes to paravirt.c
  x86/paravirt: Introduce new paravirt-base.h header
  x86/paravirt: Move paravirt_sched_clock() related code into tsc.c
  x86/paravirt: Use common code for paravirt_steal_clock()
  riscv/paravirt: Use common code for paravirt_steal_clock()
  loongarch/paravirt: Use common code for paravirt_steal_clock()
  arm64/paravirt: Use common code for paravirt_steal_clock()
  arm/paravirt: Use common code for paravirt_steal_clock()
  sched: Move clock related paravirt code to kernel/sched
  paravirt: Remove asm/paravirt_api_clock.h
  x86/paravirt: Move thunk macros to paravirt_types.h
  ...
2026-02-10 19:01:45 -08:00
Michael Kelley
afefdb2bc9 x86/hyperv: Update comment in hyperv_cleanup()
The comment in hyperv_cleanup() became out-of-date as a result of
commit c8ed081264 ("x86/hyperv: Use direct call to hypercall-page").

Update the comment. No code or functional change.

Signed-off-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-02-04 06:50:00 +00:00
Michael Kelley
5ed8cbcacc x86/hyperv: Use memremap()/memunmap() instead of ioremap_cache()/iounmap()
When running with a paravisor and SEV-SNP, the GHCB page is provided
by the paravisor instead of being allocated by Linux. The provided page
is normal memory, but is outside of the physical address space seen by
Linux. As such it cannot be accessed via the kernel's direct map, and
must be explicitly mapped to a kernel virtual address.

Current code uses ioremap_cache() and iounmap() to map and unmap the page.
These functions are for use on I/O address space that may not behave as
normal memory, so they generate or expect addresses with the __iomem
attribute. For normal memory, the preferred functions are memremap() and
memunmap(), which operate similarly but without __iomem.

At the time of the original work on CoCo VMs on Hyper-V, memremap() did not
support creating a decrypted mapping, so ioremap_cache() was used instead,
since I/O address space is always mapped decrypted. memremap() has since
been enhanced to allow decrypted mappings, so replace ioremap_cache() with
memremap() when mapping the GHCB page. Similarly, replace iounmap() with
memunmap(). As a side benefit, the replacement cleans up 'sparse' warnings
about __iomem mismatches.

The replacement is done to use the correct functions as long-term goodness
and to clean up the sparse warnings. No runtime bugs are fixed.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202311111925.iPGGJik4-lkp@intel.com/
Signed-off-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-02-04 06:29:45 +00:00
Mukesh R
c3a6ae7ea2 x86/hyperv: Move hv crash init after hypercall pg setup
hv_root_crash_init() is not setting up the hypervisor crash collection
for baremetal cases because when it's called, hypervisor page is not
setup.

Fix is simple, just move the crash init call after the hypercall
page setup.

Signed-off-by: Mukesh Rathor <mrathor@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-02-04 06:26:29 +00:00
Mukesh R
956efd32f9 x86/hyperv: fix a compiler warning in hv_crash.c
Fix a compiler warning that status is defined by not used.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202512301641.FC6OAbGM-lkp@intel.com/
Signed-off-by: Mukesh R <mrathor@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2026-02-04 06:11:38 +00:00
Ingo Molnar
ac059ae422 x86/hyperv: Fix smp_ops build failure on UP kernels
CI testing found this build failure:

  arch/x86/hyperv/hv_crash.c:631:9: error: ‘smp_ops’ undeclared (first use in this function)

And I bisected it back to the initial commit that enabled this feature:

  77c860d2db is the first bad commit
  commit 77c860d2db (HEAD)
  Author: Mukesh Rathor <mrathor@linux.microsoft.com>
  Date:   Mon Oct 6 15:42:08 2025 -0700

  x86/hyperv: Enable build of hypervisor crashdump collection files

Hyperv should probably be limited to SMP kernels, as nobody
appears to be testing it on UP kernels.

Until then, fix the smp_ops assumption. Build tested only.

Fixes: 77c860d2db ("x86/hyperv: Enable build of hypervisor crashdump collection files")
Cc: Mukesh Rathor <mrathor@linux.microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2026-01-28 11:54:04 +01:00
Juergen Gross
b0b449e6fe x86/pvlocks: Move paravirt spinlock functions into own header
Instead of having the pv spinlock function definitions in paravirt.h,
move them into the new header paravirt-spinlock.h.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://patch.msgid.link/20260105110520.21356-22-jgross@suse.com
2026-01-13 14:57:45 +01:00
Juergen Gross
07f2961235 x86/paravirt: Remove not needed includes of paravirt.h
In some places asm/paravirt.h is included without really being needed.

Remove the related #include statements.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260105110520.21356-2-jgross@suse.com
2026-01-12 11:26:52 +01:00
Linus Torvalds
d552fc632c x86/hv: Add gitignore entry for generated header file
Commit 7bfe3b8ea6 ("Drivers: hv: Introduce mshv_vtl driver") added a
new generated header file for the offsets into the mshv_vtl_cpu_context
structure to be used by the low-level assembly code.  But it didn't add
the .gitignore file to go with it, so 'git status' and friends will
mention it.

Let's add the gitignore file before somebody thinks that generated
header should be committed.

Fixes: 7bfe3b8ea6 ("Drivers: hv: Introduce mshv_vtl driver")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2025-12-13 19:57:41 +12:00
Linus Torvalds
feb06d2690 hyperv-next for v6.19
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Merge tag 'hyperv-next-signed-20251207' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull hyperv updates from Wei Liu:

 - Enhancements to Linux as the root partition for Microsoft Hypervisor:
     - Support a new mode called L1VH, which allows Linux to drive the
       hypervisor running the Azure Host directly
     - Support for MSHV crash dump collection
     - Allow Linux's memory management subsystem to better manage guest
       memory regions
     - Fix issues that prevented a clean shutdown of the whole system on
       bare metal and nested configurations
     - ARM64 support for the MSHV driver
     - Various other bug fixes and cleanups

 - Add support for Confidential VMBus for Linux guest on Hyper-V

 - Secure AVIC support for Linux guests on Hyper-V

 - Add the mshv_vtl driver to allow Linux to run as the secure kernel in
   a higher virtual trust level for Hyper-V

* tag 'hyperv-next-signed-20251207' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (58 commits)
  mshv: Cleanly shutdown root partition with MSHV
  mshv: Use reboot notifier to configure sleep state
  mshv: Add definitions for MSHV sleep state configuration
  mshv: Add support for movable memory regions
  mshv: Add refcount and locking to mem regions
  mshv: Fix huge page handling in memory region traversal
  mshv: Move region management to mshv_regions.c
  mshv: Centralize guest memory region destruction
  mshv: Refactor and rename memory region handling functions
  mshv: adjust interrupt control structure for ARM64
  Drivers: hv: use kmalloc_array() instead of kmalloc()
  mshv: Add ioctl for self targeted passthrough hvcalls
  Drivers: hv: Introduce mshv_vtl driver
  Drivers: hv: Export some symbols for mshv_vtl
  static_call: allow using STATIC_CALL_TRAMP_STR() from assembly
  mshv: Extend create partition ioctl to support cpu features
  mshv: Allow mappings that overlap in uaddr
  mshv: Fix create memory region overlap check
  mshv: add WQ_PERCPU to alloc_workqueue users
  Drivers: hv: Use kmalloc_array() instead of kmalloc()
  ...
2025-12-09 06:10:17 +09:00
Praveen K Paladugu
f0be2600ac mshv: Use reboot notifier to configure sleep state
Configure sleep state information from ACPI in MSHV hypervisor using
a reboot notifier. This data allows the hypervisor to correctly power
off the host during shutdown.

Signed-off-by: Praveen K Paladugu <prapal@linux.microsoft.com>
Co-developed-by: Anatol Belski <anbelski@linux.microsoft.com>
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Reviewed-by: Easwar Hariharan <easwar.hariharan@linux.microsoft.com>
Reviewed-by: Stansialv Kinsburskii <skinsburskii@linux.miscrosoft.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-12-05 23:25:01 +00:00
Naman Jain
7bfe3b8ea6 Drivers: hv: Introduce mshv_vtl driver
Provide an interface for Virtual Machine Monitor like OpenVMM and its
use as OpenHCL paravisor to control VTL0 (Virtual trust Level).
Expose devices and support IOCTLs for features like VTL creation,
VTL0 memory management, context switch, making hypercalls,
mapping VTL0 address space to VTL2 userspace, getting new VMBus
messages and channel events in VTL2 etc.

Co-developed-by: Roman Kisel <romank@linux.microsoft.com>
Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Co-developed-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Naman Jain <namjain@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-12-05 23:16:26 +00:00
Mukesh Rathor
77c860d2db x86/hyperv: Enable build of hypervisor crashdump collection files
Enable build of the new files introduced in the earlier commits and add
call to do the setup during boot.

Signed-off-by: Mukesh Rathor <mrathor@linux.microsoft.com>
[ wei: fix build ]
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:16 +00:00
Mukesh Rathor
94212d3461 x86/hyperv: Implement hypervisor RAM collection into vmcore
Introduce a new file to implement collection of hypervisor RAM into the
vmcore collected by linux. By default, the hypervisor RAM is locked, ie,
protected via hw page table. Hyper-V implements a disable hypercall which
essentially devirtualizes the system on the fly. This mechanism makes the
hypervisor RAM accessible to linux. Because the hypervisor RAM is already
mapped into linux address space (as reserved RAM), it is automatically
collected into the vmcore without extra work. More details of the
implementation are available in the file prologue.

Signed-off-by: Mukesh Rathor <mrathor@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:16 +00:00
Mukesh Rathor
b0574ba755 x86/hyperv: Add trampoline asm code to transition from hypervisor
Introduce a small asm stub to transition from the hypervisor to Linux
after devirtualization. Devirtualization means disabling hypervisor on
the fly, so after it is done, the code is running on physical processor
instead of virtual, and hypervisor is gone. This can be done by a
root vm only.

At a high level, during panic of either the hypervisor or the root,
the NMI handler asks hypervisor to devirtualize. As part of that,
the arguments include an entry point to return back to Linux. This asm
stub implements that entry point.

The stub is entered in protected mode, uses temporary gdt and page table
to enable long mode and get to kernel entry point which then restores full
kernel context to resume execution to kexec.

Signed-off-by: Mukesh Rathor <mrathor@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:16 +00:00
Tianyu Lan
5e52db91d1 x86/hyperv: Allow Hyper-V to inject STIMER0 interrupts
When Secure AVIC is enabled, call Secure AVIC
function to allow Hyper-V to inject STIMER0 interrupt.

Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Tianyu Lan <tiala@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:14 +00:00
Tianyu Lan
3e1b611515 drivers: hv: Allow vmbus message synic interrupt injected from Hyper-V
When Secure AVIC is enabled, VMBus driver should
call x2apic Secure AVIC interface to allow Hyper-V
to inject VMBus message interrupt.

Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Tianyu Lan <tiala@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:14 +00:00
Tianyu Lan
f34f5e576f x86/hyperv: Don't use hv apic driver when Secure AVIC is available
When Secure AVIC is available, the AMD x2apic Secure
AVIC driver will be selected. In that case, have
hv_apic_init() return immediately without doing
anything.

Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Tianyu Lan <tiala@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:14 +00:00
Thierry Reding
a97fbc3ee3 syscore: Pass context data to callbacks
Several drivers can benefit from registering per-instance data along
with the syscore operations. To achieve this, move the modifiable fields
out of the syscore_ops structure and into a separate struct syscore that
can be registered with the framework. Add a void * driver data field for
drivers to store contextual data that will be passed to the syscore ops.

Acked-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
2025-11-14 10:01:52 +01:00
Linus Torvalds
9591fdb061 - Remove a bunch of asm implementing condition flags testing in KVM's
emulator in favor of int3_emulate_jcc() which is written in C
 
 - Replace KVM fastops with C-based stubs which avoids problems with the
   fastop infra related to latter not adhering to the C ABI due to their
   special calling convention and, more importantly, bypassing compiler
   control-flow integrity checking because they're written in asm
 
 - Remove wrongly used static branches and other ugliness accumulated
   over time in hyperv's hypercall implementation with a proper static
   function call to the correct hypervisor call variant
 
 - Add some fixes and modifications to allow running FRED-enabled kernels
   in KVM even on non-FRED hardware
 
 - Add kCFI improvements like validating indirect calls and prepare for
   enabling kCFI with GCC. Add cmdline params documentation and other
   code cleanups
 
 - Use the single-byte 0xd6 insn as the official #UD single-byte
   undefined opcode instruction as agreed upon by both x86 vendors
 
 - Other smaller cleanups and touchups all over the place
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Merge tag 'x86_core_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull more x86 updates from Borislav Petkov:

 - Remove a bunch of asm implementing condition flags testing in KVM's
   emulator in favor of int3_emulate_jcc() which is written in C

 - Replace KVM fastops with C-based stubs which avoids problems with the
   fastop infra related to latter not adhering to the C ABI due to their
   special calling convention and, more importantly, bypassing compiler
   control-flow integrity checking because they're written in asm

 - Remove wrongly used static branches and other ugliness accumulated
   over time in hyperv's hypercall implementation with a proper static
   function call to the correct hypervisor call variant

 - Add some fixes and modifications to allow running FRED-enabled
   kernels in KVM even on non-FRED hardware

 - Add kCFI improvements like validating indirect calls and prepare for
   enabling kCFI with GCC. Add cmdline params documentation and other
   code cleanups

 - Use the single-byte 0xd6 insn as the official #UD single-byte
   undefined opcode instruction as agreed upon by both x86 vendors

 - Other smaller cleanups and touchups all over the place

* tag 'x86_core_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  x86,retpoline: Optimize patch_retpoline()
  x86,ibt: Use UDB instead of 0xEA
  x86/cfi: Remove __noinitretpoline and __noretpoline
  x86/cfi: Add "debug" option to "cfi=" bootparam
  x86/cfi: Standardize on common "CFI:" prefix for CFI reports
  x86/cfi: Document the "cfi=" bootparam options
  x86/traps: Clarify KCFI instruction layout
  compiler_types.h: Move __nocfi out of compiler-specific header
  objtool: Validate kCFI calls
  x86/fred: KVM: VMX: Always use FRED for IRQs when CONFIG_X86_FRED=y
  x86/fred: Play nice with invoking asm_fred_entry_from_kvm() on non-FRED hardware
  x86/fred: Install system vector handlers even if FRED isn't fully enabled
  x86/hyperv: Use direct call to hypercall-page
  x86/hyperv: Clean up hv_do_hypercall()
  KVM: x86: Remove fastops
  KVM: x86: Convert em_salc() to C
  KVM: x86: Introduce EM_ASM_3WCL
  KVM: x86: Introduce EM_ASM_1SRC2
  KVM: x86: Introduce EM_ASM_2CL
  KVM: x86: Introduce EM_ASM_2W
  ...
2025-10-11 11:19:16 -07:00
Nam Cao
4691db0704 x86/hyperv: Switch to msi_create_parent_irq_domain()
Move away from the legacy MSI domain setup, switch to use
msi_create_parent_irq_domain().

While doing the conversion, I noticed that hv_irq_compose_msi_msg() is
doing more than it is supposed to (composing message content). The
interrupt allocation bits should be moved into hv_msi_domain_alloc().
However, I have no hardware to test this change, therefore I leave a TODO
note.

Signed-off-by: Nam Cao <namcao@linutronix.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-09-30 22:50:48 +00:00
Vitaly Kuznetsov
7ad8c34f24 x86/hyperv: Add kexec/kdump support on Azure CVMs
Azure CVM instance types featuring a paravisor hang upon kdump. The
investigation shows that makedumpfile causes a hang when it steps on a page
which was previously share with the host
(HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY). The new kernel has no
knowledge of these 'special' regions (which are Vmbus connection pages,
GPADL buffers, ...). There are several ways to approach the issue:
- Convey the knowledge about these regions to the new kernel somehow.
- Unshare these regions before accessing in the new kernel (it is unclear
if there's a way to query the status for a given GPA range).
- Unshare these regions before jumping to the new kernel (which this patch
implements).

To make the procedure as robust as possible, store PFN ranges of shared
regions in a linked list instead of storing GVAs and re-using
hv_vtom_set_host_visibility(). This also allows to avoid memory allocation
on the kdump/kexec path.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Tianyu Lan <tiala@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-09-30 22:49:24 +00:00
Peter Zijlstra
c8ed081264 x86/hyperv: Use direct call to hypercall-page
Instead of using an indirect call to the hypercall page, use a direct
call instead. This avoids all CFI problems, including the one where
the hypercall page doesn't have IBT on.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lkml.kernel.org/r/20250714103441.011387946@infradead.org
2025-08-18 14:23:07 +02:00
Peter Zijlstra
0e20f1f4c2 x86/hyperv: Clean up hv_do_hypercall()
What used to be a simple few instructions has turned into a giant mess
(for x86_64). Not only does it use static_branch wrong, it mixes it
with dynamic branches for no apparent reason.

Notably it uses static_branch through an out-of-line function call,
which completely defeats the purpose, since instead of a simple
JMP/NOP site, you get a CALL+RET+TEST+Jcc sequence in return, which is
absolutely idiotic.

Add to that a dynamic test of hyperv_paravisor_present, something
which is set once and never changed.

Replace all this idiocy with a single direct function call to the
right hypercall variant.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lkml.kernel.org/r/20250714103440.897136093@infradead.org
2025-08-18 14:23:07 +02:00
Stanislav Kinsburskii
52a45f870e x86/hyperv: Expose hv_map_msi_interrupt()
Move some of the logic of hv_irq_compose_irq_message() into
hv_map_msi_interrupt(). Make hv_map_msi_interrupt() a globally-available
helper function, which will be used to map PCI interrupts when running
in the root partition.

Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/1752261532-7225-3-git-send-email-nunodasneves@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <1752261532-7225-3-git-send-email-nunodasneves@linux.microsoft.com>
2025-07-15 06:24:16 +00:00
Nuno Das Neves
faab52b59b x86/hyperv: Clean up hv_map/unmap_interrupt() return values
Fix the return values of these hypercall helpers so they return
a negated errno either directly or via hv_result_to_errno().

Update the callers to check for errno instead of using
hv_status_success(), and remove redundant error printing.

While at it, rearrange some variable declarations to adhere to style
guidelines i.e. "reverse fir tree order".

Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/1751582677-30930-5-git-send-email-nunodasneves@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <1751582677-30930-5-git-send-email-nunodasneves@linux.microsoft.com>
2025-07-09 23:49:25 +00:00
Nuno Das Neves
bb169f80ed x86/hyperv: Fix usage of cpu_online_mask to get valid cpu
Accessing cpu_online_mask here is problematic because the cpus read lock
is not held in this context.

However, cpu_online_mask isn't needed here since the effective affinity
mask is guaranteed to be valid in this callback. So, just use
cpumask_first() to get the cpu instead of ANDing it with cpus_online_mask
unnecessarily.

Fixes: e39397d1fd ("x86/hyperv: implement an MSI domain for root partition")
Reported-by: Michael Kelley <mhklinux@outlook.com>
Closes: https://lore.kernel.org/linux-hyperv/SN6PR02MB4157639630F8AD2D8FD8F52FD475A@SN6PR02MB4157.namprd02.prod.outlook.com/
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/1751582677-30930-4-git-send-email-nunodasneves@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <1751582677-30930-4-git-send-email-nunodasneves@linux.microsoft.com>
2025-07-09 23:49:25 +00:00