Commit Graph

1396695 Commits

Author SHA1 Message Date
Anirudh Rayabharam (Microsoft)
c720e6a873 mshv: Add ioctl for self targeted passthrough hvcalls
Allow MSHV_ROOT_HVCALL IOCTL on the /dev/mshv fd. This IOCTL would
execute a passthrough hypercall targeting the root/parent partition
i.e. HV_PARTITION_ID_SELF.

This will be useful for the VMM to query things like supported
synthetic processor features, supported VMM capabiliites etc.

Since hypercalls targeting the host partition could potentially perform
privileged operations, allow only a limited set of hypercalls. To begin
with, allow only:

	HVCALL_GET_PARTITION_PROPERTY
	HVCALL_GET_PARTITION_PROPERTY_EX

Signed-off-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
Reviewed-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-12-05 23:16:49 +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
Naman Jain
cffe9f58de Drivers: hv: Export some symbols for mshv_vtl
MSHV_VTL driver is going to be introduced, which is supposed to
provide interface for Virtual Machine Monitors (VMMs) to control
Virtual Trust Level (VTL). Export the symbols needed
to make it work (vmbus_isr, hv_context and hv_post_message).

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>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202506110544.q0NDMQVc-lkp@intel.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>
2025-11-15 06:18:17 +00:00
Naman Jain
796ef5a7fe static_call: allow using STATIC_CALL_TRAMP_STR() from assembly
STATIC_CALL_TRAMP_STR() could not be used from .S files because
static_call_types.h was not safe to include in assembly as it pulled in C
types/constructs that are unavailable under __ASSEMBLY__.
Make the header assembly-friendly by adding __ASSEMBLY__ checks and
providing only the minimal definitions needed for assembly, so that it
can be safely included by .S code. This enables emitting the static call
trampoline symbol name via STATIC_CALL_TRAMP_STR() directly in assembly
sources, to be used with 'call' instruction. Also, move a certain
definitions out of __ASSEMBLY__ checks in compiler_types.h to meet
the dependencies.

No functional change for C compilation.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Naman Jain <namjain@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:17 +00:00
Muminul Islam
c91fe5f162 mshv: Extend create partition ioctl to support cpu features
The existing mshv create partition ioctl does not provide a way to
specify which cpu features are enabled in the guest. Instead, it
attempts to enable all features and those that are not supported are
silently disabled by the hypervisor.

This was done to reduce unnecessary complexity and is sufficient for
many cases. However, new scenarios require fine-grained control over
these features.

Define a new mshv_create_partition_v2 structure which supports
passing the disabled processor and xsave feature bits through to the
create partition hypercall directly.

Introduce a new flag MSHV_PT_BIT_CPU_AND_XSAVE_FEATURES which enables
the new structure. If unset, the original mshv_create_partition struct
is used, with the old behavior of enabling all features.

Co-developed-by: Jinank Jain <jinankjain@microsoft.com>
Signed-off-by: Jinank Jain <jinankjain@microsoft.com>
Signed-off-by: Muminul Islam <muislam@microsoft.com>
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:17 +00:00
Magnus Kulke
f91bc8f61a mshv: Allow mappings that overlap in uaddr
Currently the MSHV driver rejects mappings that would overlap in
userspace.

Some VMMs require the same memory to be mapped to different parts of
the guest's address space, and so working around this restriction is
difficult.

The hypervisor itself doesn't prohibit mappings that overlap in uaddr,
(really in SPA; system physical addresses), so supporting this in the
driver doesn't require any extra work: only the checks need to be
removed.

Since no userspace code until now has been able to overlap regions in
userspace, relaxing this constraint can't break any existing code.

Signed-off-by: Magnus Kulke <magnuskulke@linux.microsoft.com>
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:17 +00:00
Nuno Das Neves
ba9eb9b86d mshv: Fix create memory region overlap check
The current check is incorrect; it only checks if the beginning or end
of a region is within an existing region. This doesn't account for
userspace specifying a region that begins before and ends after an
existing region.

Change the logic to a range intersection check against gfns and uaddrs
for each region.

Remove mshv_partition_region_by_uaddr() as it is no longer used.

Fixes: 621191d709 ("Drivers: hv: Introduce mshv_root module to expose /dev/mshv to VMMs")
Reported-by: Michael Kelley <mhklinux@outlook.com>
Closes: https://lore.kernel.org/linux-hyperv/SN6PR02MB41575BE0406D3AB22E1D7DB5D4C2A@SN6PR02MB4157.namprd02.prod.outlook.com/
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:17 +00:00
Marco Crivellari
8ec6070fc8 mshv: add WQ_PERCPU to alloc_workqueue users
Currently if a user enqueues a work item using schedule_delayed_work() the
used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use
WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to
schedule_work() that is using system_wq and queue_work(), that makes use
again of WORK_CPU_UNBOUND.

This lack of consistency cannot be addressed without refactoring the API.

alloc_workqueue() treats all queues as per-CPU by default, while unbound
workqueues must opt-in via WQ_UNBOUND.

This default is suboptimal: most workloads benefit from unbound queues,
allowing the scheduler to place worker threads where they’re needed and
reducing noise when CPUs are isolated.

This continues the effort to refactor workqueue APIs, which began with
the introduction of new workqueues and a new alloc_workqueue flag in:

commit 128ea9f6cc ("workqueue: Add system_percpu_wq and system_dfl_wq")
commit 930c2ea566 ("workqueue: Add new WQ_PERCPU flag")

This change adds a new WQ_PERCPU flag to explicitly request
alloc_workqueue() to be per-cpu when WQ_UNBOUND has not been specified.

With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND),
any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND
must now use WQ_PERCPU.

Once migration is complete, WQ_UNBOUND can be removed and unbound will
become the implicit default.

Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:17 +00:00
Rahul Kumar
22cb2f06fa Drivers: hv: Use kmalloc_array() instead of kmalloc()
Documentation/process/deprecated.rst recommends against the use of
kmalloc with dynamic size calculations due to the risk of overflow and
smaller allocation being made than the caller was expecting.

Replace kmalloc() with kmalloc_array() in hv_common.c to make the
intended allocation size clearer and avoid potential overflow issues.

The number of pages (pgcount) is bounded, so overflow is not a
practical concern here. However, using kmalloc_array() better reflects
the intent to allocate an array and improves consistency with other
allocations.

No functional change intended.

Signed-off-by: Rahul Kumar <rk0006818@gmail.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:17 +00:00
Stanislav Kinsburskii
5f4b5edcb1 Drivers: hv: Resolve ambiguity in hypervisor version log
Update the log message in hv_common_init to explicitly state that the
reported version is for the Microsoft Hypervisor, not the host OS.

Previously, this message was accurate for guests running on Windows
hosts, where the host and hypervisor versions matched. With support for
Linux hosts running the Hyper-V hypervisor, the host OS and hypervisor
versions may differ.

This change avoids confusion by making it clear that the version refers to
the Microsoft Hypervisor regardless of the host operating system.

Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Reviewed-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:17 +00:00
Kriish Sharma
6626f815a1 Drivers: hv: fix missing kernel-doc description for 'size' in request_arr_init()
Add missing kernel-doc entry for the @size parameter in
request_arr_init(), fixing the following documentation warning
reported by the kernel test robot and detected via kernel-doc:

Warning: drivers/hv/channel.c:595 function parameter 'size' not described in 'request_arr_init'

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202503021934.wH1BERla-lkp@intel.com
Signed-off-by: Kriish Sharma <kriish.sharma2006@gmail.com>
Reviewed-by: Easwar Hariharan <easwar.hariharan@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:16 +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
Mukesh Rathor
e0a975ecd2 hyperv: Add definitions for hypervisor crash dump support
Add data structures for hypervisor crash dump support to the hypervisor
host ABI header file. Details of their usages are in subsequent commits.

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
56c3feb3cc hyperv: Add two new hypercall numbers to guest ABI public header
In preparation for the subsequent crashdump patches, copy two hypercall
numbers to the guest ABI header published by Hyper-V. One to notify
hypervisor of an event that occurs in the root partition, other to ask
hypervisor to disable the hypervisor.

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
91a076d304 x86/hyperv: Rename guest crash shutdown function
Rename hv_machine_crash_shutdown to more appropriate
hv_guest_crash_shutdown and make it applicable to guests only. This
in preparation for the subsequent hypervisor root crash support
patches.

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
Jiapeng Chong
77c3a45a0f x86: mshyperv: Remove duplicate asm/msr.h header
./arch/x86/kernel/cpu/mshyperv.c: asm/msr.h is included more than once.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=26164
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:16 +00:00
Long Li
428ca2d4c6 MAINTAINERS: Add Long Li as a Hyper-V maintainer
Also include MANA RDMA driver in the Hyper-V maintained list.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:16 +00:00
Jinank Jain
d62313bdf5 mshv: Introduce new hypercall to map stats page for L1VH partitions
Introduce HVCALL_MAP_STATS_PAGE2 which provides a map location (GPFN)
to map the stats to. This hypercall is required for L1VH partitions,
depending on the hypervisor version. This uses the same check as the
state page map location; mshv_use_overlay_gpfn().

Add mshv_map_vp_state_page() helpers to use this new hypercall or the
old one depending on availability.

For unmapping, the original HVCALL_UNMAP_STATS_PAGE works for both
cases.

Signed-off-by: Jinank Jain <jinankjain@linux.microsoft.com>
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: Easwar Hariharan <easwar.hariharan@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:16 +00:00
Jinank Jain
19c515c27c mshv: Allocate vp state page for HVCALL_MAP_VP_STATE_PAGE on L1VH
Introduce mshv_use_overlay_gpfn() to check if a page needs to be
allocated and passed to the hypervisor to map VP state pages. This is
only needed on L1VH, and only on some (newer) versions of the
hypervisor, hence the need to check vmm_capabilities.

Introduce functions hv_map/unmap_vp_state_page() to handle the
allocation and freeing.

Signed-off-by: Jinank Jain <jinankjain@linux.microsoft.com>
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: Praveen K Paladugu <prapal@linux.microsoft.com>
Reviewed-by: Easwar Hariharan <easwar.hariharan@linux.microsoft.com>
Reviewed-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Reviewed-by: Anirudh Rayabharam <anirudh@anirudhrb.com>
Reviewed-by: Tianyu Lan <tiala@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:16 +00:00
Purna Pavan Chandra Aekkaladevi
fd612d97a4 mshv: Get the vmm capabilities offered by the hypervisor
Some hypervisor APIs are gated by feature bits in the
"vmm capabilities" partition property. Store the capabilities on
mshv_root module init, using HVCALL_GET_PARTITION_PROPERTY_EX.

This is not supported on all hypervisors. In that case, just set the
capabilities to 0 and proceed as normal.

Signed-off-by: Purna Pavan Chandra Aekkaladevi <paekkaladevi@linux.microsoft.com>
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: Praveen K Paladugu <prapal@linux.microsoft.com>
Reviewed-by: Easwar Hariharan <easwar.hariharan@linux.microsoft.com>
Reviewed-by: Tianyu Lan <tiala@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:16 +00:00
Purna Pavan Chandra Aekkaladevi
59aeea1959 mshv: Add the HVCALL_GET_PARTITION_PROPERTY_EX hypercall
This hypercall can be used to fetch extended properties of a
partition. Extended properties are properties with values larger than
a u64. Some of these also need additional input arguments.

Add helper function for using the hypercall in the mshv_root driver.

Signed-off-by: Purna Pavan Chandra Aekkaladevi <paekkaladevi@linux.microsoft.com>
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: Anirudh Rayabharam <anirudh@anirudhrb.com>
Reviewed-by: Praveen K Paladugu <prapal@linux.microsoft.com>
Reviewed-by: Easwar Hariharan <easwar.hariharan@linux.microsoft.com>
Reviewed-by: Tianyu Lan <tiala@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:16 +00:00
Nuno Das Neves
9ebc528cfd mshv: Only map vp->vp_stats_pages if on root scheduler
This mapping is only used for checking if the dispatch thread is
blocked. This is only relevant for the root scheduler, so check the
scheduler type to determine whether to map/unmap these pages, instead of
the current check, which is incorrect.

Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: Anirudh Rayabharam <anirudh@anirudhrb.com>
Reviewed-by: Praveen K Paladugu <prapal@linux.microsoft.com>
Reviewed-by: Easwar Hariharan <easwar.hariharan@linux.microsoft.com>
Reviewed-by: Tianyu Lan <tiala@microsoft.com>
Acked-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Reviewed-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:15 +00:00
Roman Kisel
2647c96649 Drivers: hv: Support establishing the confidential VMBus connection
To establish the confidential VMBus connection the CoCo VM, the guest
first checks on the confidential VMBus availability, and then proceeds
to initializing the communication stack.

Implement that in the VMBus driver initialization.

Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:15 +00:00
Roman Kisel
b537794bc2 Drivers: hv: Set the default VMBus version to 6.0
The confidential VMBus is supported by the protocol version
6.0 onwards.

Attempt to establish the VMBus 6.0 connection thus enabling
the confidential VMBus features when available.

Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:15 +00:00
Roman Kisel
bf35d298bb Drivers: hv: Support confidential VMBus channels
To make use of Confidential VMBus channels, initialize the
co_ring_buffers and co_external_memory fields of the channel
structure.

Advertise support upon negotiating the version and compute
values for those fields and initialize them.

Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:15 +00:00
Roman Kisel
510164539f Drivers: hv: Free msginfo when the buffer fails to decrypt
The early failure path in __vmbus_establish_gpadl() doesn't deallocate
msginfo if the buffer fails to decrypt.

Fix the leak by breaking out the cleanup code into a separate function
and calling it where required.

Fixes: d4dccf353d ("Drivers: hv: vmbus: Mark vmbus ring buffer visible to host in Isolation VM")
Reported-by: Michael Kelley <mkhlinux@outlook.com>
Closes: https://lore.kernel.org/linux-hyperv/SN6PR02MB41573796F9787F67E0E97049D472A@SN6PR02MB4157.namprd02.prod.outlook.com
Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:15 +00:00
Roman Kisel
0a4534bdf2 Drivers: hv: Allocate encrypted buffers when requested
Confidential VMBus is built around using buffers not shared with
the host.

Support allocating encrypted buffers when requested.

Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Tianyu Lan <tiala@microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:15 +00:00
Roman Kisel
e096fe2bd6 Drivers: hv: Functions for setting up and tearing down the paravisor SynIC
The confidential VMBus runs with the paravisor SynIC and requires
configuring it with the paravisor.

Add the functions for configuring the paravisor SynIC. Update
overall SynIC initialization logic to initialize the SynIC if it
is present. Finally, break out SynIC interrupt enable/disable
code into separate functions so that SynIC interrupts can be
enabled or disabled via the paravisor instead of the hypervisor
if the paravisor SynIC is present.

Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:15 +00:00
Roman Kisel
74fa5d7e5f Drivers: hv: Rename the SynIC enable and disable routines
The confidential VMBus requires support for the both hypervisor
facing SynIC and the paravisor one.

Rename the functions that enable and disable SynIC with the
hypervisor. No functional changes.

Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Tianyu Lan <tiala@microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:15 +00:00
Roman Kisel
09406f2f84 Drivers: hv: Check message and event pages for non-NULL before iounmap()
It might happen that some hyp SynIC pages aren't allocated.

Check for that and only then call iounmap().

Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Tianyu Lan <tiala@microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:15 +00:00
Roman Kisel
1bb15327d5 Drivers: hv: remove stale comment
The comment about the x2v shim is ancient and long since incorrect.

Remove the incorrect comment.

Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Tianyu Lan <tiala@microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:15 +00:00
Roman Kisel
25059d5e4c Drivers: hv: Post messages through the confidential VMBus if available
When the confidential VMBus is available, the guest should post
messages to the paravisor.

Update hv_post_message() to post messages to the paravisor rather than
through GHCB or TD calls.

Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Tianyu Lan <tiala@microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:15 +00:00
Roman Kisel
226494e5ee Drivers: hv: Allocate the paravisor SynIC pages when required
Confidential VMBus requires interacting with two SynICs -- one
provided by the host hypervisor, and one provided by the paravisor.
Each SynIC requires its own message and event pages.

Refactor and extend the existing code to add allocating and freeing
the message and event pages for the paravisor SynIC when it is
present.

Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Tianyu Lan <tiala@microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:15 +00:00
Roman Kisel
163224c189 Drivers: hv: Rename fields for SynIC message and event pages
Confidential VMBus requires interacting with two SynICs -- one
provided by the host hypervisor, and one provided by the paravisor.
Each SynIC requires its own message and event pages.

Rename the existing host-accessible SynIC message and event pages
with the "hyp_" prefix to clearly distinguish them from the paravisor
ones. The field name is also changed in mshv_root.* for consistency.

No functional changes.

Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Tianyu Lan <tiala@microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:14 +00:00
Roman Kisel
a156ad8c50 arch/x86: mshyperv: Trap on access for some synthetic MSRs
hv_set_non_nested_msr() has special handling for SINT MSRs
when a paravisor is present. In addition to updating the MSR on the
host, the mirror MSR in the paravisor is updated, including with the
proxy bit. But with Confidential VMBus, the proxy bit must not be
used, so add a special case to skip it.

Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Alok Tiwari <alok.a.tiwari@oracle.com>
Reviewed-by: Tianyu Lan <tiala@microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:14 +00:00
Roman Kisel
e6eeb3c782 arch: hyperv: Get/set SynIC synth.registers via paravisor
The existing Hyper-V wrappers for getting and setting MSRs are
hv_get/set_msr(). Via hv_get/set_non_nested_msr(), they detect
when running in a CoCo VM with a paravisor, and use the TDX or
SNP guest-host communication protocol to bypass the paravisor
and go directly to the host hypervisor for SynIC MSRs. The "set"
function also implements the required special handling for the
SINT MSRs.

Provide functions that allow manipulating the SynIC registers
through the paravisor. Move vmbus_signal_eom() to a more
appropriate location (which also avoids breaking KVM).

Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Alok Tiwari <alok.a.tiwari@oracle.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:14 +00:00
Roman Kisel
7c8b6c326d arch/x86: mshyperv: Discover Confidential VMBus availability
Confidential VMBus requires enabling paravisor SynIC, and
the x86_64 guest has to inspect the Virtualization Stack (VS)
CPUID leaf to see if Confidential VMBus is available. If it is,
the guest shall enable the paravisor SynIC.

Read the relevant data from the VS CPUID leaf. Refactor the
code to avoid repeating CPUID and add flags to the struct
ms_hyperv_info. For ARM64, the flag for Confidential VMBus
is not set which provides the desired behaviour for now as
it is not available on ARM64 just yet. Once ARM64 CCA guests
are supported, this flag will be set unconditionally when
running such a guest.

Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:14 +00:00
Roman Kisel
6802d8af47 Drivers: hv: VMBus protocol version 6.0
The confidential VMBus is supported starting from the protocol
version 6.0 onwards.

Provide the required definitions. No functional changes.

Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Alok Tiwari <alok.a.tiwari@oracle.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:14 +00:00
Roman Kisel
92c7053b44 Documentation: hyperv: Confidential VMBus
Define what the confidential VMBus is and describe what advantages
it offers on the capable hardware.

Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Alok Tiwari <alok.a.tiwari@oracle.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:14 +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
c52c957e41 x86/hyperv: Don't use auto-eoi when Secure AVIC is available
Hyper-V doesn't support auto-eoi with Secure AVIC.
So set the HV_DEPRECATING_AEOI_RECOMMENDED flag
to force writing the EOI register after handling an 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
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
Nuno Das Neves
4cc1aa469c mshv: Fix deposit memory in MSHV_ROOT_HVCALL
When the MSHV_ROOT_HVCALL ioctl is executing a hypercall, and gets
HV_STATUS_INSUFFICIENT_MEMORY, it deposits memory and then returns
-EAGAIN to userspace. The expectation is that the VMM will retry.

However, some VMM code in the wild doesn't do this and simply fails.
Rather than force the VMM to retry, change the ioctl to deposit
memory on demand and immediately retry the hypercall as is done with
all the other hypercall helper functions.

In addition to making the ioctl easier to use, removing the need for
multiple syscalls improves performance.

There is a complication: unlike the other hypercall helper functions,
in MSHV_ROOT_HVCALL the input is opaque to the kernel. This is
problematic for rep hypercalls, because the next part of the input
list can't be copied on each loop after depositing pages (this was
the original reason for returning -EAGAIN in this case).

Introduce hv_do_rep_hypercall_ex(), which adds a 'rep_start'
parameter. This solves the issue, allowing the deposit loop in
MSHV_ROOT_HVCALL to restart a rep hypercall after depositing pages
partway through.

Fixes: 621191d709 ("Drivers: hv: Introduce mshv_root module to expose /dev/mshv to VMMs")
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:14 +00:00
Nuno Das Neves
7563d021e2 mshv: Fix VpRootDispatchThreadBlocked value
This value in the VP stats page is used to track if the VP can be
dispatched for execution when there are no fast interrupts injected.

The original value of 201 was used in a version of the hypervisor
which did not ship. It was subsequently changed to 202 so that is the
correct value.

Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
2025-11-15 06:18:14 +00:00
Linus Torvalds
3a86608788 Linux 6.18-rc1 2025-10-12 13:42:36 -07:00
Linus Torvalds
3dd7b81235 i2c-for-6.18-rc1-hotfix
One revert because of a regression in the I2C core which has sadly not
 showed up during its time in -next.
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Merge tag 'i2c-for-6.18-rc1-hotfix' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

Pull i2c fix from Wolfram Sang:
 "One revert because of a regression in the I2C core which has sadly not
  showed up during its time in -next"

* tag 'i2c-for-6.18-rc1-hotfix' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  Revert "i2c: boardinfo: Annotate code used in init phase only"
2025-10-12 13:27:56 -07:00
Linus Torvalds
8765f46791 - Skip interrupt ID 0 in sifive-plic during suspend/resume because ID 0 is
reserved and accessing reserved register space could result in undefined
   behavior
 
 - Fix a function's retval check in aspeed-scu-ic
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Merge tag 'irq_urgent_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull irq fixes from Borislav Petkov:

 - Skip interrupt ID 0 in sifive-plic during suspend/resume because
   ID 0 is reserved and accessing reserved register space could result
   in undefined behavior

 - Fix a function's retval check in aspeed-scu-ic

* tag 'irq_urgent_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/sifive-plic: Avoid interrupt ID 0 handling during suspend/resume
  irqchip/aspeed-scu-ic: Fix an IS_ERR() vs NULL check
2025-10-12 08:45:52 -07:00