- Expand the KVM_PRE_FAULT_MEMORY selftest to add a regression test for the
bug fixed by commit 3ccbf6f47098 ("KVM: x86/mmu: Return -EAGAIN if userspace
deletes/moves memslot during prefault")
- Don't try to get PMU capabbilities from perf when running a CPU with hybrid
CPUs/PMUs, as perf will rightly WARN.
- Rework KVM_CAP_GUEST_MEMFD_MMAP (newly introduced in 6.18) into a more
generic KVM_CAP_GUEST_MEMFD_FLAGS
- Add a guest_memfd INIT_SHARED flag and require userspace to explicitly set
said flag to initialize memory as SHARED, irrespective of MMAP. The
behavior merged in 6.18 is that enabling mmap() implicitly initializes
memory as SHARED, which would result in an ABI collision for x86 CoCo VMs
as their memory is currently always initialized PRIVATE.
- Allow mmap() on guest_memfd for x86 CoCo VMs, i.e. on VMs with private
memory, to enable testing such setups, i.e. to hopefully flush out any
other lurking ABI issues before 6.18 is officially released.
- Add testcases to the guest_memfd selftest to cover guest_memfd without MMAP,
and host userspace accesses to mmap()'d private memory.
-----BEGIN PGP SIGNATURE-----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=lBtj
-----END PGP SIGNATURE-----
Merge tag 'kvm-x86-fixes-6.18-rc2' of https://github.com/kvm-x86/linux into HEAD
KVM x86 fixes for 6.18:
- Expand the KVM_PRE_FAULT_MEMORY selftest to add a regression test for the
bug fixed by commit 3ccbf6f47098 ("KVM: x86/mmu: Return -EAGAIN if userspace
deletes/moves memslot during prefault")
- Don't try to get PMU capabbilities from perf when running a CPU with hybrid
CPUs/PMUs, as perf will rightly WARN.
- Rework KVM_CAP_GUEST_MEMFD_MMAP (newly introduced in 6.18) into a more
generic KVM_CAP_GUEST_MEMFD_FLAGS
- Add a guest_memfd INIT_SHARED flag and require userspace to explicitly set
said flag to initialize memory as SHARED, irrespective of MMAP. The
behavior merged in 6.18 is that enabling mmap() implicitly initializes
memory as SHARED, which would result in an ABI collision for x86 CoCo VMs
as their memory is currently always initialized PRIVATE.
- Allow mmap() on guest_memfd for x86 CoCo VMs, i.e. on VMs with private
memory, to enable testing such setups, i.e. to hopefully flush out any
other lurking ABI issues before 6.18 is officially released.
- Add testcases to the guest_memfd selftest to cover guest_memfd without MMAP,
and host userspace accesses to mmap()'d private memory.
The KVM_IRQFD ioctl fails if no irqchip is present in-kernel, which
isn't too surprising as there's not much KVM can do for an IRQ if it
cannot resolve a destination.
As written the irqfd_test assumes that a 'default' VM created in
selftests has an in-kernel irqchip created implicitly. That may be the
case on x86 but it isn't necessarily true on other architectures.
Add an arch predicate indicating if 'default' VMs get an irqchip and
make the irqfd_test depend on it. Work around arm64 VGIC initialization
requirements by using vm_create_with_one_vcpu(), ignoring the created
vCPU as it isn't used for the test.
Reported-by: Sebastian Ott <sebott@redhat.com>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Acked-by: Sean Christopherson <seanjc@google.com>
Fixes: 7e9b231c402a ("KVM: selftests: Add a KVM_IRQFD test to verify uniqueness requirements")
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
A defect against the architecture now allows an implementation to treat
AMO as 1 when HCR_EL2.{E2H, TGE} = {1, 0}. KVM now takes advantage of
this interpretation to address a quality of emulation issue w.r.t.
SError injection.
Add a corresponding test case and expect a pending SError to be taken.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Extract the guest_memfd test's SIGBUS handling functionality into a common
TEST_EXPECT_SIGBUS() macro in anticipation of adding more SIGBUS testcases.
Eating a SIGBUS isn't terrible difficult, but it requires a non-trivial
amount of boilerplate code, and using a macro allows selftests to print
out the exact action that failed to generate a SIGBUS without the developer
needing to remember to add a useful error message.
Explicitly mark the SIGBUS handler as "used", as gcc-14 at least likes to
discard the function before linking.
Opportunistically use TEST_FAIL(...) instead of TEST_ASSERT(false, ...),
and fix the write path of the guest_memfd test to use the local "val"
instead of hardcoding the literal value a second time.
Suggested-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Tested-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Lisa Wang <wyihan@google.com>
Tested-by: Lisa Wang <wyihan@google.com>
Link: https://lore.kernel.org/r/20251003232606.4070510-12-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Add and use wrappers for mmap() and munmap() that assert success to reduce
a significant amount of boilerplate code, to ensure all tests assert on
failure, and to provide consistent error messages on failure.
No functional change intended.
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Link: https://lore.kernel.org/r/20251003232606.4070510-10-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Add support for virtualizing Control-flow Enforcement Technology (CET) on
Intel (Shadow Stacks and Indirect Branch Tracking) and AMD (Shadow Stacks).
CET is comprised of two distinct features, Shadow Stacks (SHSTK) and Indirect
Branch Tracking (IBT), that can be utilized by software to help provide
Control-flow integrity (CFI). SHSTK defends against backward-edge attacks
(a.k.a. Return-oriented programming (ROP)), while IBT defends against
forward-edge attacks (a.k.a. similarly CALL/JMP-oriented programming (COP/JOP)).
Attackers commonly use ROP and COP/JOP methodologies to redirect the control-
flow to unauthorized targets in order to execute small snippets of code,
a.k.a. gadgets, of the attackers choice. By chaining together several gadgets,
an attacker can perform arbitrary operations and circumvent the system's
defenses.
SHSTK defends against backward-edge attacks, which execute gadgets by modifying
the stack to branch to the attacker's target via RET, by providing a second
stack that is used exclusively to track control transfer operations. The
shadow stack is separate from the data/normal stack, and can be enabled
independently in user and kernel mode.
When SHSTK is is enabled, CALL instructions push the return address on both the
data and shadow stack. RET then pops the return address from both stacks and
compares the addresses. If the return addresses from the two stacks do not
match, the CPU generates a Control Protection (#CP) exception.
IBT defends against backward-edge attacks, which branch to gadgets by executing
indirect CALL and JMP instructions with attacker controlled register or memory
state, by requiring the target of indirect branches to start with a special
marker instruction, ENDBRANCH. If an indirect branch is executed and the next
instruction is not an ENDBRANCH, the CPU generates a #CP. Note, ENDBRANCH
behaves as a NOP if IBT is disabled or unsupported.
From a virtualization perspective, CET presents several problems. While SHSTK
and IBT have two layers of enabling, a global control in the form of a CR4 bit,
and a per-feature control in user and kernel (supervisor) MSRs (U_CET and S_CET
respectively), the {S,U}_CET MSRs can be context switched via XSAVES/XRSTORS.
Practically speaking, intercepting and emulating XSAVES/XRSTORS is not a viable
option due to complexity, and outright disallowing use of XSTATE to context
switch SHSTK/IBT state would render the features unusable to most guests.
To limit the overall complexity without sacrificing performance or usability,
simply ignore the potential virtualization hole, but ensure that all paths in
KVM treat SHSTK/IBT as usable by the guest if the feature is supported in
hardware, and the guest has access to at least one of SHSTK or IBT. I.e. allow
userspace to advertise one of SHSTK or IBT if both are supported in hardware,
even though doing so would allow a misbehaving guest to use the unadvertised
feature.
Fully emulating SHSTK and IBT would also require significant complexity, e.g.
to track and update branch state for IBT, and shadow stack state for SHSTK.
Given that emulating large swaths of the guest code stream isn't necessary on
modern CPUs, punt on emulating instructions that meaningful impact or consume
SHSTK or IBT. However, instead of doing nothing, explicitly reject emulation
of such instructions so that KVM's emulator can't be abused to circumvent CET.
Disable support for SHSTK and IBT if KVM is configured such that emulation of
arbitrary guest instructions may be required, specifically if Unrestricted
Guest (Intel only) is disabled, or if KVM will emulate a guest.MAXPHYADDR that
is smaller than host.MAXPHYADDR.
Lastly disable SHSTK support if shadow paging is enabled, as the protections
for the shadow stack are novel (shadow stacks require Writable=0,Dirty=1, so
that they can't be directly modified by software), i.e. would require
non-trivial support in the Shadow MMU.
Note, AMD CPUs currently only support SHSTK. Explicitly disable IBT support
so that KVM doesn't over-advertise if AMD CPUs add IBT, and virtualizing IBT
in SVM requires KVM modifications.
-----BEGIN PGP SIGNATURE-----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=zsBl
-----END PGP SIGNATURE-----
Merge tag 'kvm-x86-cet-6.18' of https://github.com/kvm-x86/linux into HEAD
KVM x86 CET virtualization support for 6.18
Add support for virtualizing Control-flow Enforcement Technology (CET) on
Intel (Shadow Stacks and Indirect Branch Tracking) and AMD (Shadow Stacks).
CET is comprised of two distinct features, Shadow Stacks (SHSTK) and Indirect
Branch Tracking (IBT), that can be utilized by software to help provide
Control-flow integrity (CFI). SHSTK defends against backward-edge attacks
(a.k.a. Return-oriented programming (ROP)), while IBT defends against
forward-edge attacks (a.k.a. similarly CALL/JMP-oriented programming (COP/JOP)).
Attackers commonly use ROP and COP/JOP methodologies to redirect the control-
flow to unauthorized targets in order to execute small snippets of code,
a.k.a. gadgets, of the attackers choice. By chaining together several gadgets,
an attacker can perform arbitrary operations and circumvent the system's
defenses.
SHSTK defends against backward-edge attacks, which execute gadgets by modifying
the stack to branch to the attacker's target via RET, by providing a second
stack that is used exclusively to track control transfer operations. The
shadow stack is separate from the data/normal stack, and can be enabled
independently in user and kernel mode.
When SHSTK is is enabled, CALL instructions push the return address on both the
data and shadow stack. RET then pops the return address from both stacks and
compares the addresses. If the return addresses from the two stacks do not
match, the CPU generates a Control Protection (#CP) exception.
IBT defends against backward-edge attacks, which branch to gadgets by executing
indirect CALL and JMP instructions with attacker controlled register or memory
state, by requiring the target of indirect branches to start with a special
marker instruction, ENDBRANCH. If an indirect branch is executed and the next
instruction is not an ENDBRANCH, the CPU generates a #CP. Note, ENDBRANCH
behaves as a NOP if IBT is disabled or unsupported.
From a virtualization perspective, CET presents several problems. While SHSTK
and IBT have two layers of enabling, a global control in the form of a CR4 bit,
and a per-feature control in user and kernel (supervisor) MSRs (U_CET and S_CET
respectively), the {S,U}_CET MSRs can be context switched via XSAVES/XRSTORS.
Practically speaking, intercepting and emulating XSAVES/XRSTORS is not a viable
option due to complexity, and outright disallowing use of XSTATE to context
switch SHSTK/IBT state would render the features unusable to most guests.
To limit the overall complexity without sacrificing performance or usability,
simply ignore the potential virtualization hole, but ensure that all paths in
KVM treat SHSTK/IBT as usable by the guest if the feature is supported in
hardware, and the guest has access to at least one of SHSTK or IBT. I.e. allow
userspace to advertise one of SHSTK or IBT if both are supported in hardware,
even though doing so would allow a misbehaving guest to use the unadvertised
feature.
Fully emulating SHSTK and IBT would also require significant complexity, e.g.
to track and update branch state for IBT, and shadow stack state for SHSTK.
Given that emulating large swaths of the guest code stream isn't necessary on
modern CPUs, punt on emulating instructions that meaningful impact or consume
SHSTK or IBT. However, instead of doing nothing, explicitly reject emulation
of such instructions so that KVM's emulator can't be abused to circumvent CET.
Disable support for SHSTK and IBT if KVM is configured such that emulation of
arbitrary guest instructions may be required, specifically if Unrestricted
Guest (Intel only) is disabled, or if KVM will emulate a guest.MAXPHYADDR that
is smaller than host.MAXPHYADDR.
Lastly disable SHSTK support if shadow paging is enabled, as the protections
for the shadow stack are novel (shadow stacks require Writable=0,Dirty=1, so
that they can't be directly modified by software), i.e. would require
non-trivial support in the Shadow MMU.
Note, AMD CPUs currently only support SHSTK. Explicitly disable IBT support
so that KVM doesn't over-advertise if AMD CPUs add IBT, and virtualizing IBT
in SVM requires KVM modifications.
- Add #DE coverage in the fastops test (the only exception that's guest-
triggerable in fastop-emulated instructions).
- Fix PMU selftests errors encountered on Granite Rapids (GNR), Sierra
Forest (SRF) and Clearwater Forest (CWF).
- Minor cleanups and improvements
-----BEGIN PGP SIGNATURE-----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=A/nr
-----END PGP SIGNATURE-----
Merge tag 'kvm-x86-selftests-6.18' of https://github.com/kvm-x86/linux into HEAD
KVM selftests changes for 6.18
- Add #DE coverage in the fastops test (the only exception that's guest-
triggerable in fastop-emulated instructions).
- Fix PMU selftests errors encountered on Granite Rapids (GNR), Sierra
Forest (SRF) and Clearwater Forest (CWF).
- Minor cleanups and improvements
- Added SBI FWFT extension for Guest/VM with misaligned
delegation and pointer masking PMLEN features
- Added ONE_REG interface for SBI FWFT extension
- Added Zicbop and bfloat16 extensions for Guest/VM
- Enabled more common KVM selftests for RISC-V such as
access_tracking_perf_test, dirty_log_perf_test,
memslot_modification_stress_test, memslot_perf_test,
mmu_stress_test, and rseq_test
- Added SBI v3.0 PMU enhancements in KVM and perf driver
-----BEGIN PGP SIGNATURE-----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=BCyU
-----END PGP SIGNATURE-----
Merge tag 'kvm-riscv-6.18-1' of https://github.com/kvm-riscv/linux into HEAD
KVM/riscv changes for 6.18
- Added SBI FWFT extension for Guest/VM with misaligned
delegation and pointer masking PMLEN features
- Added ONE_REG interface for SBI FWFT extension
- Added Zicbop and bfloat16 extensions for Guest/VM
- Enabled more common KVM selftests for RISC-V such as
access_tracking_perf_test, dirty_log_perf_test,
memslot_modification_stress_test, memslot_perf_test,
mmu_stress_test, and rseq_test
- Added SBI v3.0 PMU enhancements in KVM and perf driver
* kvm-arm64/selftests-6.18:
: .
: KVM/arm64 selftest updates for 6.18:
:
: - Large update to run EL1 selftests at EL2 when possible
: (20250917212044.294760-1-oliver.upton@linux.dev)
:
: - Work around lack of ID_AA64MMFR4_EL1 trapping on CPUs
: without FEAT_FGT
: (20250923173006.467455-1-oliver.upton@linux.dev)
:
: - Additional fixes and cleanups
: (20250920-kvm-arm64-id-aa64isar3-el1-v1-0-1764c1c1c96d@kernel.org)
: .
KVM: arm64: selftests: Cover ID_AA64ISAR3_EL1 in set_id_regs
KVM: arm64: selftests: Remove a duplicate register listing in set_id_regs
KVM: arm64: selftests: Cope with arch silliness in EL2 selftest
KVM: arm64: selftests: Add basic test for running in VHE EL2
KVM: arm64: selftests: Enable EL2 by default
KVM: arm64: selftests: Initialize HCR_EL2
KVM: arm64: selftests: Use the vCPU attr for setting nr of PMU counters
KVM: arm64: selftests: Use hyp timer IRQs when test runs at EL2
KVM: arm64: selftests: Select SMCCC conduit based on current EL
KVM: arm64: selftests: Provide helper for getting default vCPU target
KVM: arm64: selftests: Alias EL1 registers to EL2 counterparts
KVM: arm64: selftests: Create a VGICv3 for 'default' VMs
KVM: arm64: selftests: Add unsanitised helpers for VGICv3 creation
KVM: arm64: selftests: Add helper to check for VGICv3 support
KVM: arm64: selftests: Initialize VGICv3 only once
KVM: arm64: selftests: Provide kvm_arch_vm_post_create() in library code
Signed-off-by: Marc Zyngier <maz@kernel.org>
Take advantage of VHE to implicitly promote KVM selftests to run at EL2
with only slight modification. Update the smccc_filter test to account
for this now that the EL2-ness of a VM is visible to tests.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Arch timer registers are redirected to their hypervisor counterparts
when running in VHE EL2. This is great, except for the fact that the
hypervisor timers use different PPIs. Use the correct INTIDs when that
is the case.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
HVCs are taken within the VM when EL2 is in use. Ensure tests use the
SMC instruction when running at EL2 to interact with the host.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
The default vCPU target in KVM selftests is pretty boring in that it
doesn't enable any vCPU features. Expose a helper for getting the
default target to prepare for cramming in more features. Call
KVM_ARM_PREFERRED_TARGET directly from get-reg-list as it needs
fine-grained control over feature flags.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Reviewed-by: Itaru Kitayama <itaru.kitayama@fujitsu.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
FEAT_VHE has the somewhat nice property of implicitly redirecting EL1
register aliases to their corresponding EL2 representations when E2H=1.
Unfortunately, there's no such abstraction for userspace and EL2
registers are always accessed by their canonical encoding.
Introduce a helper that applies EL2 redirections to sysregs and use
aggressive inlining to catch misuse at compile time. Go a little past
the architectural definition for ease of use for test authors (e.g. the
stack pointer).
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Start creating a VGICv3 by default unless explicitly opted-out by the
test. While having an interrupt controller is nice, the real benefit
here is clearing a hurdle for EL2 VMs which mandate the presence of a
VGIC.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
vgic_v3_setup() has a good bit of sanity checking internally to ensure
that vCPUs have actually been created and match the dimensioning of the
vgic itself. Spin off an unsanitised setup and initialization helper so
vgic initialization can be wired in around a 'default' VM's vCPU
creation.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Introduce a proper predicate for probing VGICv3 by performing a 'test'
creation of the device on a dummy VM.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
In order to compel the default usage of EL2 in selftests, move
kvm_arch_vm_post_create() to library code and expose an opt-in for using
MTE by default.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Add a selftest to verify reads and writes to various MSRs, from both the
guest and host, and expect success/failure based on whether or not the
vCPU supports the MSR according to supported CPUID.
Note, this test is extremely similar to KVM-Unit-Test's "msr" test, but
provides more coverage with respect to host accesses, and will be extended
to provide addition testing of CPUID-based features, save/restore lists,
and KVM_{G,S}ET_ONE_REG, all which are extremely difficult to validate in
KUT.
If kvm.ignore_msrs=true, skip the unsupported and reserved testcases as
KVM's ABI is a mess; what exactly is supposed to be ignored, and when,
varies wildly.
Reviewed-by: Chao Gao <chao.gao@intel.com>
Link: https://lore.kernel.org/r/20250919223258.1604852-46-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Steal exception_mnemonic() from KVM-Unit-Tests as ex_str() (to keep line
lengths reasonable) and use it in assert messages that currently print the
raw vector number.
Co-developed-by: Chao Gao <chao.gao@intel.com>
Signed-off-by: Chao Gao <chao.gao@intel.com>
Link: https://lore.kernel.org/r/20250919223258.1604852-45-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Add a PMU errata framework and use it to relax precise event counts on
Atom platforms that overcount "Instruction Retired" and "Branch Instruction
Retired" events, as the overcount issues on VM-Exit/VM-Entry are impossible
to prevent from userspace, e.g. the test can't prevent host IRQs.
Setup errata during early initialization and automatically sync the mask
to VMs so that tests can check for errata without having to manually
manage host=>guest variables.
For Intel Atom CPUs, the PMU events "Instruction Retired" or
"Branch Instruction Retired" may be overcounted for some certain
instructions, like FAR CALL/JMP, RETF, IRET, VMENTRY/VMEXIT/VMPTRLD
and complex SGX/SMX/CSTATE instructions/flows.
The detailed information can be found in the errata (section SRF7):
https://edc.intel.com/content/www/us/en/design/products-and-solutions/processors-and-chipsets/sierra-forest/xeon-6700-series-processor-with-e-cores-specification-update/errata-details/
For the Atom platforms before Sierra Forest (including Sierra Forest),
Both 2 events "Instruction Retired" and "Branch Instruction Retired" would
be overcounted on these certain instructions, but for Clearwater Forest
only "Instruction Retired" event is overcounted on these instructions.
Signed-off-by: dongsheng <dongsheng.x.zhang@intel.com>
Co-developed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Tested-by: Yi Lai <yi1.lai@intel.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Tested-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Link: https://lore.kernel.org/r/20250919214648.1585683-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Add support for 5 new architectural events (4 topdown level 1 metrics
events and LBR inserts event) that will first show up in Intel's
Clearwater Forest CPUs. Detailed info about the new events can be found
in SDM section 21.2.7 "Pre-defined Architectural Performance Events".
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Tested-by: Yi Lai <yi1.lai@intel.com>
[sean: drop "unavailable_mask" changes]
Tested-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Link: https://lore.kernel.org/r/20250919214648.1585683-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Add a basic test corrupting a level-2 table entry to check that
the resulting abort is a SEA on a PTW at level-3.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Add support for handling #DE (divide error) exceptions in KVM selftests
so that the fastops test can verify KVM correctly handles #DE when
emulating DIV or IDIV on behalf of the guest. Morph #DE to 0xff (i.e.
to -1) as a mostly-arbitrary vector to indicate #DE, so that '0' (the
real #DE vector) can still be used to indicate "no exception".
Link: https://lore.kernel.org/r/20250909202835.333554-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Move the x86 specific helpers for getting kvm_{amd,intel} module params to
x86 where they belong. Expose the module-agnostic helpers globally, there
is nothing secret about the logic.
Link: https://lore.kernel.org/r/20250806225159.1687326-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
- Host driver for GICv5, the next generation interrupt controller for
arm64, including support for interrupt routing, MSIs, interrupt
translation and wired interrupts.
- Use FEAT_GCIE_LEGACY on GICv5 systems to virtualize GICv3 VMs on
GICv5 hardware, leveraging the legacy VGIC interface.
- Userspace control of the 'nASSGIcap' GICv3 feature, allowing
userspace to disable support for SGIs w/o an active state on hardware
that previously advertised it unconditionally.
- Map supporting endpoints with cacheable memory attributes on systems
with FEAT_S2FWB and DIC where KVM no longer needs to perform cache
maintenance on the address range.
- Nested support for FEAT_RAS and FEAT_DoubleFault2, allowing the guest
hypervisor to inject external aborts into an L2 VM and take traps of
masked external aborts to the hypervisor.
- Convert more system register sanitization to the config-driven
implementation.
- Fixes to the visibility of EL2 registers, namely making VGICv3 system
registers accessible through the VGIC device instead of the ONE_REG
vCPU ioctls.
- Various cleanups and minor fixes.
-----BEGIN PGP SIGNATURE-----
iI0EABYIADUWIQSNXHjWXuzMZutrKNKivnWIJHzdFgUCaIezbRccb2xpdmVyLnVw
dG9uQGxpbnV4LmRldgAKCRCivnWIJHzdFr/eAQDY5NIG5cR6ZcAWnPQLmGWpz2ou
pq4Jhn9E/mGR3n5L1AEAsJpfLLpOsmnLBdwfbjmW59gGsa8k3i5tjWEOJ6yzAwk=
=r+sp
-----END PGP SIGNATURE-----
Merge tag 'kvmarm-6.17' of https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 changes for 6.17, round #1
- Host driver for GICv5, the next generation interrupt controller for
arm64, including support for interrupt routing, MSIs, interrupt
translation and wired interrupts.
- Use FEAT_GCIE_LEGACY on GICv5 systems to virtualize GICv3 VMs on
GICv5 hardware, leveraging the legacy VGIC interface.
- Userspace control of the 'nASSGIcap' GICv3 feature, allowing
userspace to disable support for SGIs w/o an active state on hardware
that previously advertised it unconditionally.
- Map supporting endpoints with cacheable memory attributes on systems
with FEAT_S2FWB and DIC where KVM no longer needs to perform cache
maintenance on the address range.
- Nested support for FEAT_RAS and FEAT_DoubleFault2, allowing the guest
hypervisor to inject external aborts into an L2 VM and take traps of
masked external aborts to the hypervisor.
- Convert more system register sanitization to the config-driven
implementation.
- Fixes to the visibility of EL2 registers, namely making VGICv3 system
registers accessible through the VGIC device instead of the ONE_REG
vCPU ioctls.
- Various cleanups and minor fixes.
KVM selftests changes for 6.17
- Fix a comment typo.
- Verify KVM is loaded when getting any KVM module param so that attempting to
run a selftest without kvm.ko loaded results in a SKIP message about KVM not
being loaded/enabled, versus some random parameter not existing.
- SKIP tests that hit EACCES when attempting to access a file, with a "Root
required?" help message. In most cases, the test just needs to be run with
elevated permissions.
KVM x86 misc changes for 6.17
- Prevert the host's DEBUGCTL.FREEZE_IN_SMM (Intel only) when running the
guest. Failure to honor FREEZE_IN_SMM can bleed host state into the guest.
- Explicitly check vmcs12.GUEST_DEBUGCTL on nested VM-Enter (Intel only) to
prevent L1 from running L2 with features that KVM doesn't support, e.g. BTF.
- Intercept SPEC_CTRL on AMD if the MSR shouldn't exist according to the
vCPU's CPUID model.
- Rework the MSR interception code so that the SVM and VMX APIs are more or
less identical.
- Recalculate all MSR intercepts from the "source" on MSR filter changes, and
drop the dedicated "shadow" bitmaps (and their awful "max" size defines).
- WARN and reject loading kvm-amd.ko instead of panicking the kernel if the
nested SVM MSRPM offsets tracker can't handle an MSR.
- Advertise support for LKGS (Load Kernel GS base), a new instruction that's
loosely related to FRED, but is supported and enumerated independently.
- Fix a user-triggerable WARN that syzkaller found by stuffing INIT_RECEIVED,
a.k.a. WFS, and then putting the vCPU into VMX Root Mode (post-VMXON). Use
the same approach KVM uses for dealing with "impossible" emulation when
running a !URG guest, and simply wait until KVM_RUN to detect that the vCPU
has architecturally impossible state.
- Add KVM_X86_DISABLE_EXITS_APERFMPERF to allow disabling interception of
APERF/MPERF reads, so that a "properly" configured VM can "virtualize"
APERF/MPERF (with many caveats).
- Reject KVM_SET_TSC_KHZ if vCPUs have been created, as changing the "default"
frequency is unsupported for VMs with a "secure" TSC, and there's no known
use case for changing the default frequency for other VM types.
Expand kvm_pin_this_task_to_pcpu() into a set of APIs to allow pinning a
task (or self) to a CPU (any or specific). This will allow deduplicating
code throughout a variety of selftests.
Opportunistically use "self" instead of "this_task" as it is both more
concise and less ambiguous.
Link: https://lore.kernel.org/r/20250626001225.744268-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Add tests for SError injection considering KVM is more directly involved
in delivery:
- Pending SErrors are taken at the first CSE after SErrors are unmasked
- Pending SErrors aren't taken and remain pending if SErrors are masked
- Unmasked SErrors are taken immediately when injected (implementation
detail)
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250708172532.1699409-25-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Add helpers to create eventfds and to (de)assign eventfds via KVM_IRQFD.
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250522235223.3178519-13-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Add an inner __open_path_or_exit() API to let the caller provide additional
information on ENOENT to try and help the user figure out why the test is
being skipped, e.g. for files like the page_idle bitmap needed by the
access tracking perf, which is dependent on a Kconfig.
Immediately convert /dev/kvm to the new API, both as an example and because
users might not know that some architectures/setups require loading KVM.
Link: https://lore.kernel.org/r/20250516215909.2551628-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Probe /dev/kvm when getting a KVM module param so that attempting to load
a module param super early in a selftest generates a SKIP message about
KVM not being loaded/enabled, versus some random parameter not existing.
E.g. KVM x86's unconditional retrieval of force_emulation_prefix during
kvm_selftest_arch_init() generates a rather confusing error message that
takes far too much triage to understand.
Link: https://lore.kernel.org/r/20250516215909.2551628-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
- Add support for SNP to the various SEV selftests.
- Add a selftest to verify fastops instructions via forced emulation.
- Add MGLRU support to the access tracking perf test.
-----BEGIN PGP SIGNATURE-----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=v9bp
-----END PGP SIGNATURE-----
Merge tag 'kvm-x86-selftests-6.16' of https://github.com/kvm-x86/linux into HEAD
KVM selftests changes for 6.16:
- Add support for SNP to the various SEV selftests.
- Add a selftest to verify fastops instructions via forced emulation.
- Add MGLRU support to the access tracking perf test.
Currently, the sbi_pmu_test continues if the exception type is illegal
instruction because access to hpmcounter will generate that. However
illegal instruction exception may occur due to the other reasons
which should result in test assertion.
Use the stval to decode the exact type of instructions and which csrs are
being accessed if it is csr access instructions. Assert in all cases
except if it is a csr access instructions that access valid PMU related
registers.
Take this opportunity to remove the CSR_CYCLEH reference as the test is
compiled for RV64 only.
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20250430-kvm_selftest_improve-v3-2-eea270ff080b@rivosinc.com
Signed-off-by: Anup Patel <anup@brainfault.org>
The current exeception register structure in selftests are missing
few registers (e.g stval). Instead of adding it manually, change
the ex_regs to align with pt_regs to make it future proof.
Suggested-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20250430-kvm_selftest_improve-v3-1-eea270ff080b@rivosinc.com
Signed-off-by: Anup Patel <anup@brainfault.org>
Add ucall test support for LoongArch, ucall method on LoongArch uses
undefined mmio area. It will cause vCPU exiting to hypervisor so that
hypervisor can communicate with vCPU.
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Add KVM selftests header files for LoongArch, including processor.h
and kvm_util_arch.h. It mainly contains LoongArch CSR register and page
table entry definition.
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
On LoongArch system, 16K page is used in general and GVA width is 47 bit
while GPA width is 47 bit also, here add new VM mode VM_MODE_P47V47_16K.
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Use MGLRU's debugfs interface to do access tracking instead of
page_idle. The logic to use the page_idle bitmap is left in, as it is
useful for kernels that do not have MGLRU built in.
When MGLRU is enabled, page_idle will report pages as still idle even
after being accessed, as MGLRU doesn't necessarily clear the Idle folio
flag when accessing an idle page, so the test will not attempt to use
page_idle if MGLRU is enabled but otherwise not usable.
Aging pages with MGLRU is much faster than marking pages as idle with
page_idle.
Co-developed-by: Axel Rasmussen <axelrasmussen@google.com>
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Signed-off-by: James Houghton <jthoughton@google.com>
Link: https://lore.kernel.org/r/20250508184649.2576210-8-jthoughton@google.com
[sean: print parsed features, not raw string]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Add an option to skip sanity check of number of still idle pages,
and set it by default to skip, in case hypervisor or NUMA balancing
is detected.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Co-developed-by: James Houghton <jthoughton@google.com>
Signed-off-by: James Houghton <jthoughton@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20250508184649.2576210-3-jthoughton@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Extend the SEV library to include support for SNP ioctl() wrappers,
which aid in launching and interacting with a SEV-SNP guest.
Signed-off-by: Pratik R. Sampat <prsampat@amd.com>
Link: https://lore.kernel.org/r/20250305230000.231025-8-prsampat@amd.com
[sean: use BIT()]
Signed-off-by: Sean Christopherson <seanjc@google.com>
In preparation for SNP, declutter the vm type check by introducing a
SEV-SNP VM type check as well as a transitive set of helper functions.
The SNP VM type is the subset of SEV-ES. Similarly, the SEV-ES and SNP
types are subset of the SEV VM type check.
Signed-off-by: Pratik R. Sampat <prsampat@amd.com>
Link: https://lore.kernel.org/r/20250305230000.231025-7-prsampat@amd.com
[sean: make the helpers static inlines]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Move the SMT control check out of the hyperv_cpuid selftest so that it
is generally accessible all KVM selftests. Split the functionality into
a helper that populates a buffer with SMT control value which other
helpers can use to ascertain if SMT state is available and active.
Signed-off-by: Pratik R. Sampat <prsampat@amd.com>
Link: https://lore.kernel.org/r/20250305230000.231025-5-prsampat@amd.com
[sean: prepend is_ to the helpers]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Abstract rep vmmcall coded into the vmgexit helper for the sev
library.
No functional change intended.
Signed-off-by: Pratik R. Sampat <prsampat@amd.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>
Link: https://lore.kernel.org/r/20250305230000.231025-4-prsampat@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Add the X86_FEATURE_SEV_SNP CPU feature to the architectural definition
for the SEV-SNP VM type to exercise the KVM_SEV_INIT2 call. Ensure that
the SNP test is skipped in scenarios where CPUID supports it but KVM
does not, preventing reporting of failure in such cases.
Reviewed-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Pratik R. Sampat <prsampat@amd.com>
Link: https://lore.kernel.org/r/20250305230000.231025-3-prsampat@amd.com
[sean: use the same pattern as SEV and SEV-ES]
Signed-off-by: Sean Christopherson <seanjc@google.com>
- Rework heuristics for resolving the fault IPA (HPFAR_EL2 v. re-walk
stage-1 page tables) to align with the architecture. This avoids
possibly taking an SEA at EL2 on the page table walk or using an
architecturally UNKNOWN fault IPA.
- Use acquire/release semantics in the KVM FF-A proxy to avoid reading
a stale value for the FF-A version.
- Fix KVM guest driver to match PV CPUID hypercall ABI.
- Use Inner Shareable Normal Write-Back mappings at stage-1 in KVM
selftests, which is the only memory type for which atomic
instructions are architecturally guaranteed to work.
-----BEGIN PGP SIGNATURE-----
iI0EABYIADUWIQSNXHjWXuzMZutrKNKivnWIJHzdFgUCZ/RO9hccb2xpdmVyLnVw
dG9uQGxpbnV4LmRldgAKCRCivnWIJHzdFmRuAP0YajO4qHJe1vHtCkamuPnEY0Kp
E+t2TwPafPbrPdQ1PgEAq6lHuSdUnid1r/uhRKIT+ywW8tE97eNwQAa1LFma0Ac=
=d4G5
-----END PGP SIGNATURE-----
Merge tag 'kvmarm-fixes-6.15-1' of https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64: First batch of fixes for 6.15
- Rework heuristics for resolving the fault IPA (HPFAR_EL2 v. re-walk
stage-1 page tables) to align with the architecture. This avoids
possibly taking an SEA at EL2 on the page table walk or using an
architecturally UNKNOWN fault IPA.
- Use acquire/release semantics in the KVM FF-A proxy to avoid reading
a stale value for the FF-A version.
- Fix KVM guest driver to match PV CPUID hypercall ABI.
- Use Inner Shareable Normal Write-Back mappings at stage-1 in KVM
selftests, which is the only memory type for which atomic
instructions are architecturally guaranteed to work.
Atomic instructions such as 'ldset' in the guest have been observed to
cause an EL1 data abort with FSC 0x35 (IMPLEMENTATION DEFINED fault
(Unsupported Exclusive or Atomic access)) on Neoverse-N3.
Per DDI0487L.a B2.2.6, atomic instructions are only architecturally
guaranteed for Inner/Outer Shareable Normal Write-Back memory. For
anything else the behavior is IMPLEMENTATION DEFINED and can lose
atomicity, or, in this case, generate an abort.
It would appear that selftests sets up the stage-1 mappings as Non
Shareable, leading to the observed abort. Explicitly set the
Shareability field to Inner Shareable for non-LPA2 page tables. Note
that for the LPA2 page table format, translations for cacheable memory
inherit the shareability attribute of the PTW, i.e. TCR_ELx.SH{0,1}.
Suggested-by: Oliver Upton <oupton@google.com>
Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Link: https://lore.kernel.org/r/20250405001042.1470552-3-rananta@google.com
[oliver: Rephrase changelog]
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
