Commit Graph

64 Commits

Author SHA1 Message Date
Sean Christopherson
947ab90c91 KVM: selftests: Verify MSRs are (not) in save/restore list when (un)supported
Add a check in the MSRs test to verify that KVM's reported support for
MSRs with feature bits is consistent between KVM's MSR save/restore lists
and KVM's supported CPUID.

To deal with Intel's wonderful decision to bundle IBT and SHSTK under CET,
track the "second" feature to avoid false failures when running on a CPU
with only one of IBT or SHSTK.

Reviewed-by: Chao Gao <chao.gao@intel.com>
Link: https://lore.kernel.org/r/20250919223258.1604852-51-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-09-23 10:03:02 -07:00
Sean Christopherson
3469fd203b KVM: selftests: Add coverage for KVM-defined registers in MSRs test
Add test coverage for the KVM-defined GUEST_SSP "register" in the MSRs
test.  While _KVM's_ goal is to not tie the uAPI of KVM-defined registers
to any particular internal implementation, i.e. to not commit in uAPI to
handling GUEST_SSP as an MSR, treating GUEST_SSP as an MSR for testing
purposes is a-ok and is a naturally fit given the semantics of SSP.

Reviewed-by: Chao Gao <chao.gao@intel.com>
Link: https://lore.kernel.org/r/20250919223258.1604852-50-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-09-23 09:59:44 -07:00
Sean Christopherson
80c2b6d8e7 KVM: selftests: Add KVM_{G,S}ET_ONE_REG coverage to MSRs test
When KVM_{G,S}ET_ONE_REG are supported, verify that MSRs can be accessed
via ONE_REG and through the dedicated MSR ioctls.  For simplicity, run
the test twice, e.g. instead of trying to get MSR values into the exact
right state when switching write methods.

Reviewed-by: Chao Gao <chao.gao@intel.com>
Link: https://lore.kernel.org/r/20250919223258.1604852-49-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-09-23 09:52:18 -07:00
Sean Christopherson
a8b9cca99c KVM: selftests: Extend MSRs test to validate vCPUs without supported features
Add a third vCPUs to the MSRs test that runs with all features disabled in
the vCPU's CPUID model, to verify that KVM does the right thing with
respect to emulating accesses to MSRs that shouldn't exist.  Use the same
VM to verify that KVM is honoring the vCPU model, e.g. isn't looking at
per-VM state when emulating MSR accesses.

Link: https://lore.kernel.org/r/20250919223258.1604852-48-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-09-23 09:52:17 -07:00
Sean Christopherson
27c4135306 KVM: selftests: Add support for MSR_IA32_{S,U}_CET to MSRs test
Extend the MSRs test to support {S,U}_CET, which are a bit of a pain to
handled due to the MSRs existing if IBT *or* SHSTK is supported.  To deal
with Intel's wonderful decision to bundle IBT and SHSTK under CET, track
the second feature, but skip only RDMSR #GP tests to avoid false failures
when running on a CPU with only one of IBT or SHSTK (the WRMSR #GP tests
are still valid since the enable bits are per-feature).

Reviewed-by: Chao Gao <chao.gao@intel.com>
Link: https://lore.kernel.org/r/20250919223258.1604852-47-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-09-23 09:51:59 -07:00
Sean Christopherson
9c38ddb3df KVM: selftests: Add an MSR test to exercise guest/host and read/write
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>
2025-09-23 09:51:56 -07:00
Sean Christopherson
1f2bbbbbda KVM: x86: Merge 'selftests' into 'cet' to pick up ex_str()
Merge the queue of KVM selftests changes for 6.18 to pick up the ex_str()
helper so that it can be used to pretty print expected versus actual
exceptions in a new MSR selftest.  CET virtualization will add support for
several MSRs with non-trivial semantics, along with new uAPI for accessing
the guest's Shadow Stack Pointer (SSP) from userspace.
2025-09-23 09:00:18 -07:00
Sean Christopherson
df1f294013 KVM: selftests: Add ex_str() to print human friendly name of exception vectors
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>
2025-09-23 08:39:02 -07:00
Sukrut Heroorkar
ff86b48d4c selftests/kvm: remove stale TODO in xapic_state_test
The TODO about using the number of vCPUs instead of vcpu.id + 1
was already addressed by commit 376bc1b458 ("KVM: selftests: Don't
assume vcpu->id is '0' in xAPIC state test"). The comment is now
stale and can be removed.

Signed-off-by: Sukrut Heroorkar <hsukrut3@gmail.com>
Link: https://lore.kernel.org/r/20250908210547.12748-1-hsukrut3@gmail.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-09-23 08:39:01 -07:00
dongsheng
c435978e4f KVM: selftests: Handle Intel Atom errata that leads to PMU event overcount
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>
2025-09-23 08:38:59 -07:00
Dapeng Mi
2922b59588 KVM: selftests: Validate more arch-events in pmu_counters_test
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>
2025-09-23 08:38:59 -07:00
Sean Christopherson
1fcd3053aa KVM: selftests: Reduce number of "unavailable PMU events" combos tested
Reduce the number of combinations of unavailable PMU events masks that are
testing by the PMU counters test.  In reality, testing every possible
combination isn't all that interesting, and certainly not worth the tens
of seconds (or worse, minutes) of runtime.  Fully testing the N^2 space
will be especially problematic in the near future, as 5! new arch events
are on their way.

Use alternating bit patterns (and 0 and -1u) in the hopes that _if_ there
is ever a KVM bug, it's not something horribly convoluted that shows up
only with a super specific pattern/value.

Reported-by: Dapeng Mi <dapeng1.mi@linux.intel.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/20250919214648.1585683-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-09-23 08:38:59 -07:00
Sean Christopherson
571fc2833e KVM: selftests: Track unavailable_mask for PMU events as 32-bit value
Track the mask of "unavailable" PMU events as a 32-bit value.  While bits
31:9 are currently reserved, silently truncating those bits is unnecessary
and asking for missed coverage.  To avoid running afoul of the sanity check
in vcpu_set_cpuid_property(), explicitly adjust the mask based on the
non-reserved bits as reported by KVM's supported CPUID.

Opportunistically update the "all ones" testcase to pass -1u instead of
0xff.

Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Tested-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Link: https://lore.kernel.org/r/20250919214648.1585683-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-09-23 08:38:59 -07:00
Dapeng Mi
210b09fa42 KVM: selftests: Add timing_info bit support in vmx_pmu_caps_test
A new bit PERF_CAPABILITIES[17] called "PEBS_TIMING_INFO" bit is added
to indicated if PEBS supports to record timing information in a new
"Retried Latency" field.

Since KVM requires user can only set host consistent PEBS capabilities,
otherwise the PERF_CAPABILITIES setting would fail, add pebs_timing_info
into the "immutable_caps" to block host inconsistent PEBS configuration
and cause errors.

Opportunistically drop the anythread_deprecated bit.  It isn't and likely
never was a PERF_CAPABILITIES flag, the test's definition snuck in when
the union was copy+pasted from the kernel's definition.

Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Tested-by: Yi Lai <yi1.lai@intel.com>
[sean: call out anythread_deprecated change]
Tested-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Link: https://lore.kernel.org/r/20250919214648.1585683-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-09-23 08:38:59 -07:00
Sean Christopherson
e8f85d7884 KVM: x86: Don't treat ENTER and LEAVE as branches, because they aren't
Remove the IsBranch flag from ENTER and LEAVE in KVM's emulator, as ENTER
and LEAVE are stack operations, not branches.  Add forced emulation of
said instructions to the PMU counters test to prove that KVM diverges from
hardware, and to guard against regressions.

Opportunistically add a missing "1 MOV" to the selftest comment regarding
the number of instructions per loop, which commit 7803339fa9 ("KVM:
selftests: Use data load to trigger LLC references/misses in Intel PMU")
forgot to add.

Fixes: 018d70ffcf ("KVM: x86: Update vPMCs when retiring branch instructions")
Cc: Jim Mattson <jmattson@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Chao Gao <chao.gao@intel.com>
Link: https://lore.kernel.org/r/20250919004639.1360453-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-09-22 07:14:05 -07:00
Sean Christopherson
aebc62b3de KVM: selftests: Add support for DIV and IDIV in the fastops test
Extend the fastops test coverage to DIV and IDIV, specifically to provide
coverage for #DE (divide error) exceptions, as #DE is the only exception
that can occur in KVM's fastops path, i.e. that requires exception fixup.

Link: https://lore.kernel.org/r/20250909202835.333554-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-09-11 08:55:44 -07:00
Sean Christopherson
fe08478b1d KVM: selftests: Dedup the gnarly constraints of the fastops tests (more macros!)
Add a fastop() macro along with macros to define its required constraints,
and use the macros to dedup the innermost guts of the fastop testcases.

No functional change intended.

Link: https://lore.kernel.org/r/20250909202835.333554-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-09-11 08:55:44 -07:00
Sean Christopherson
9bf5da1ca4 KVM: selftests: Add coverage for 'b' (byte) sized fastops emulation
Extend the fastops test to cover instructions that operate on 8-bit data.
Support for 8-bit instructions was omitted from the original commit purely
due to complications with BT not having a r/m8 variant.  To keep the
RFLAGS.CF behavior deterministic and not heavily biased to '0' or '1',
continue using BT, but cast and load the to-be-tested value into a
dedicated 32-bit constraint.

Supporting 8-bit operations will allow using guest_test_fastops() as-is to
provide full coverage for DIV and IDIV.  For divide operations, covering
all operand sizes _is_ interesting, because KVM needs provide exception
fixup for each size (failure to handle a #DE could panic the host).

Link: https://lore.kernel.org/all/aIF7ZhWZxlkcpm4y@google.com
Link: https://lore.kernel.org/r/20250909202835.333554-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-09-11 08:55:44 -07:00
Alok Tiwari
665071186c KVM: selftests: Fix typo in hyperv cpuid test message
Fix a typo in hyperv_cpuid.c test assertion log:
replace "our of supported range" -> "out of supported range".

Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>
Link: https://lore.kernel.org/r/20250824181642.629297-1-alok.a.tiwari@oracle.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-09-08 13:03:22 -07:00
Paolo Bonzini
b4733cd5be Merge tag 'kvm-x86-selftests-6.17' of https://github.com/kvm-x86/linux into HEAD
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.
2025-07-29 08:36:44 -04:00
Paolo Bonzini
1a14928e2e Merge tag 'kvm-x86-misc-6.17' of https://github.com/kvm-x86/linux into HEAD
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.
2025-07-29 08:36:43 -04:00
Paolo Bonzini
f02b1bcc73 Merge tag 'kvm-x86-irqs-6.17' of https://github.com/kvm-x86/linux into HEAD
KVM IRQ changes for 6.17

 - Rework irqbypass to track/match producers and consumers via an xarray
   instead of a linked list.  Using a linked list leads to O(n^2) insertion
   times, which is hugely problematic for use cases that create large numbers
   of VMs.  Such use cases typically don't actually use irqbypass, but
   eliminating the pointless registration is a future problem to solve as it
   likely requires new uAPI.

 - Track irqbypass's "token" as "struct eventfd_ctx *" instead of a "void *",
   to avoid making a simple concept unnecessarily difficult to understand.

 - Add CONFIG_KVM_IOAPIC for x86 to allow disabling support for I/O APIC, PIC,
   and PIT emulation at compile time.

 - Drop x86's irq_comm.c, and move a pile of IRQ related code into irq.c.

 - Fix a variety of flaws and bugs in the AVIC device posted IRQ code.

 - Inhibited AVIC if a vCPU's ID is too big (relative to what hardware
   supports) instead of rejecting vCPU creation.

 - Extend enable_ipiv module param support to SVM, by simply leaving IsRunning
   clear in the vCPU's physical ID table entry.

 - Disable IPI virtualization, via enable_ipiv, if the CPU is affected by
   erratum #1235, to allow (safely) enabling AVIC on such CPUs.

 - Dedup x86's device posted IRQ code, as the vast majority of functionality
   can be shared verbatime between SVM and VMX.

 - Harden the device posted IRQ code against bugs and runtime errors.

 - Use vcpu_idx, not vcpu_id, for GA log tag/metadata, to make lookups O(1)
   instead of O(n).

 - Generate GA Log interrupts if and only if the target vCPU is blocking, i.e.
   only if KVM needs a notification in order to wake the vCPU.

 - Decouple device posted IRQs from VFIO device assignment, as binding a VM to
   a VFIO group is not a requirement for enabling device posted IRQs.

 - Clean up and document/comment the irqfd assignment code.

 - Disallow binding multiple irqfds to an eventfd with a priority waiter, i.e.
   ensure an eventfd is bound to at most one irqfd through the entire host,
   and add a selftest to verify eventfd:irqfd bindings are globally unique.
2025-07-29 08:35:46 -04:00
Jim Mattson
df98ce784a KVM: selftests: Test behavior of KVM_X86_DISABLE_EXITS_APERFMPERF
For a VCPU thread pinned to a single LPU, verify that interleaved host
and guest reads of IA32_[AM]PERF return strictly increasing values when
APERFMPERF exiting is disabled.

Run the test in both L1 and L2 to verify that KVM passes through the
APERF and MPERF MSRs when L1 doesn't want to intercept them (or any MSRs).

Signed-off-by: Jim Mattson <jmattson@google.com>
Link: https://lore.kernel.org/r/20250530185239.2335185-4-jmattson@google.com
Co-developed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20250626001225.744268-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-07-09 09:33:41 -07:00
Chenyi Qiang
0048ca5e99 KVM: selftests: Add back the missing check of MONITOR/MWAIT availability
The revamp of monitor/mwait test missed the original check of feature
availability [*]. If MONITOR/MWAIT is not supported or is disabled by
IA32_MISC_ENABLE on the host, executing MONITOR or MWAIT instruction
from guest doesn't cause monitor/mwait VM exits, but a #UD.

[*] https://lore.kernel.org/all/20240411210237.34646-1-zide.chen@intel.com/

Reported-by: Xuelian Guo <xuelian.guo@intel.com>
Fixes: 80fd663590 ("selftests: kvm: revamp MONITOR/MWAIT tests")
Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com>
Link: https://lore.kernel.org/r/20250620062219.342930-1-chenyi.qiang@intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-06-24 12:58:19 -07:00
Sean Christopherson
74e5e3fb0d KVM: selftests: Add utilities to create eventfds and do KVM_IRQFD
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>
2025-06-23 09:51:01 -07:00
Sean Christopherson
033b76bc7f KVM: selftests: Assert that eventfd() succeeds in Xen shinfo test
Assert that eventfd() succeeds in the Xen shinfo test instead of skipping
the associated testcase.  While eventfd() is outside the scope of KVM, KVM
unconditionally selects EVENTFD, i.e. the syscall should always succeed.

Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250522235223.3178519-12-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-06-23 09:51:00 -07:00
Sean Christopherson
fcab107abe KVM: selftests: Verify KVM is loaded when getting a KVM module param
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>
2025-06-20 13:39:10 -07:00
Sean Christopherson
0792c71c1c KVM: selftests: Verify KVM disable interception (for userspace) on filter change
Re-read MSR_{FS,GS}_BASE after restoring the "allow everything" userspace
MSR filter to verify that KVM stops forwarding exits to userspace.  This
can also be used in conjunction with manual verification (e.g. printk) to
ensure KVM is correctly updating the MSR bitmaps consumed by hardware.

Tested-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Tested-by: Manali Shukla <Manali.Shukla@amd.com>
Link: https://lore.kernel.org/r/20250610225737.156318-33-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-06-20 13:07:38 -07:00
Paolo Bonzini
4e02d4f973 Merge tag 'kvm-x86-svm-6.16' of https://github.com/kvm-x86/linux into HEAD
KVM SVM changes for 6.16:

 - Wait for target vCPU to acknowledge KVM_REQ_UPDATE_PROTECTED_GUEST_STATE to
   fix a race between AP destroy and VMRUN.

 - Decrypt and dump the VMSA in dump_vmcb() if debugging enabled for the VM.

 - Add support for ALLOWED_SEV_FEATURES.

 - Add #VMGEXIT to the set of handlers special cased for CONFIG_RETPOLINE=y.

 - Treat DEBUGCTL[5:2] as reserved to pave the way for virtualizing features
   that utilize those bits.

 - Don't account temporary allocations in sev_send_update_data().

 - Add support for KVM_CAP_X86_BUS_LOCK_EXIT on SVM, via Bus Lock Threshold.
2025-05-27 12:15:49 -04:00
Nikunj A Dadhania
72df72e1c6 KVM: selftests: Add test to verify KVM_CAP_X86_BUS_LOCK_EXIT
Add a test case to verify x86's bus lock exit functionality, which is now
supported on both Intel and AMD.  Trigger bus lock exits by performing a
split-lock access, i.e. an atomic access that splits two cache lines.

Verify that the correct number of bus lock exits are generated, and that
the counter is incremented correctly and at the appropriate time based on
the underlying architecture.

Generate bus locks in both L1 and L2 (if nested virtualization is enabled),
as SVM's functionality in particular requires non-trivial logic to do the
right thing when running nested VMs.

Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Co-developed-by: Manali Shukla <manali.shukla@amd.com>
Signed-off-by: Manali Shukla <manali.shukla@amd.com>
Link: https://lore.kernel.org/r/20250502050346.14274-6-manali.shukla@amd.com
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-05-19 11:05:19 -07:00
Sean Christopherson
5e9ac644c4 KVM: selftests: Add a test for x86's fastops emulation
Add a test to verify KVM's fastops emulation via forced emulation.  KVM's
so called "fastop" infrastructure executes the to-be-emulated instruction
directly on hardware instead of manually emulating the instruction in
software, using various shenanigans to glue together the emulator context
and CPU state, e.g. to get RFLAGS fed into the instruction and back out
for the emulator.

Add testcases for all instructions that are low hanging fruit.  While the
primary goal of the selftest is to validate the glue code, a secondary
goal is to ensure "emulation" matches hardware exactly, including for
arithmetic flags that are architecturally undefined.  While arithmetic
flags may be *architecturally* undefined, their behavior is deterministic
for a given CPU (likely a given uarch, and possibly even an entire family
or class of CPUs).  I.e. KVM has effectively been emulating underlying
hardware behavior for years.

Link: https://lore.kernel.org/r/20250506011250.1089254-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-05-08 07:16:44 -07:00
Pratik R. Sampat
ada014f5fc KVM: selftests: Add a basic SEV-SNP smoke test
Extend sev_smoke_test to also run a minimal SEV-SNP smoke test that
initializes and sets up private memory regions required to run a simple
SEV-SNP guest.

Similar to its SEV-ES smoke test counterpart, this also does not
support GHCB and ucall yet and uses the GHCB MSR protocol to trigger an
exit of the type KVM_EXIT_SYSTEM_EVENT.

Signed-off-by: Pratik R. Sampat <prsampat@amd.com>
Link: https://lore.kernel.org/r/20250305230000.231025-11-prsampat@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-05-02 13:05:32 -07:00
Pratik R. Sampat
a5d55f783f KVM: selftests: Decouple SEV policy from VM type
In preparation for SNP, cleanup the smoke test to decouple deriving type
from policy.  This will allow reusing the existing interfaces for SNP.

No functional change intended.

Signed-off-by: Pratik R. Sampat <prsampat@amd.com>
Link: https://lore.kernel.org/r/20250305230000.231025-10-prsampat@amd.com
[sean: massage shortlog+changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-05-02 13:05:32 -07:00
Pratik R. Sampat
4a4e1e8e92 KVM: selftests: Introduce SEV VM type check
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>
2025-05-02 12:32:33 -07:00
Pratik R. Sampat
acf0643450 KVM: selftests: Add SMT control state helper
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>
2025-05-02 12:32:33 -07:00
Pratik R. Sampat
c4e1a848d7 KVM: selftests: Add vmgexit helper
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>
2025-05-02 12:32:32 -07:00
Pratik R. Sampat
68ed692e39 KVM: selftests: SEV-SNP test for KVM_SEV_INIT2
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>
2025-05-02 12:32:32 -07:00
Paolo Bonzini
80fd663590 selftests: kvm: revamp MONITOR/MWAIT tests
Run each testcase in a separate VMs to cover more possibilities;
move WRMSR close to MONITOR/MWAIT to test updating CPUID bits
while in the VM.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-04-04 06:20:27 -04:00
Paolo Bonzini
783e9cd05c Merge tag 'kvm-x86-selftests-6.15' of https://github.com/kvm-x86/linux into HEAD
KVM selftests changes for 6.15, part 2

 - Fix a variety of flaws, bugs, and false failures/passes dirty_log_test, and
   improve its coverage by collecting all dirty entries on each iteration.

 - Fix a few minor bugs related to handling of stats FDs.

 - Add infrastructure to make vCPU and VM stats FDs available to tests by
   default (open the FDs during VM/vCPU creation).

 - Relax an assertion on the number of HLT exits in the xAPIC IPI test when
   running on a CPU that supports AMD's Idle HLT (which elides interception of
   HLT if a virtual IRQ is pending and unmasked).

 - Misc cleanups and fixes.
2025-03-19 09:05:34 -04:00
Paolo Bonzini
9b47f288eb Merge tag 'kvm-x86-selftests_6.15-1' of https://github.com/kvm-x86/linux into HEAD
KVM selftests changes for 6.15, part 1

 - Misc cleanups and prep work.

 - Annotate _no_printf() with "printf" so that pr_debug() statements are
   checked by the compiler for default builds (and pr_info() when QUIET).

 - Attempt to whack the last LLC references/misses mole in the Intel PMU
   counters test by adding a data load and doing CLFLUSH{OPT} on the data
   instead of the code being executed.  The theory is that modern Intel CPUs
   have learned new code prefetching tricks that bypass the PMU counters.

 - Fix a flaw in the Intel PMU counters test where it asserts that an event is
   counting correctly without actually knowing what the event counts on the
   underlying hardware.
2025-03-19 09:05:22 -04:00
Paolo Bonzini
4d9a677596 Merge tag 'kvm-x86-misc-6.15' of https://github.com/kvm-x86/linux into HEAD
KVM x86 misc changes for 6.15:

 - Fix a bug in PIC emulation that caused KVM to emit a spurious KVM_REQ_EVENT.

 - Add a helper to consolidate handling of mp_state transitions, and use it to
   clear pv_unhalted whenever a vCPU is made RUNNABLE.

 - Defer runtime CPUID updates until KVM emulates a CPUID instruction, to
   coalesce updates when multiple pieces of vCPU state are changing, e.g. as
   part of a nested transition.

 - Fix a variety of nested emulation bugs, and add VMX support for synthesizing
   nested VM-Exit on interception (instead of injecting #UD into L2).

 - Drop "support" for PV Async #PF with proctected guests without SEND_ALWAYS,
   as KVM can't get the current CPL.

 - Misc cleanups
2025-03-19 09:04:48 -04:00
Sean Christopherson
3b2d3db368 KVM: selftests: Fix printf() format goof in SEV smoke test
Print out the index of mismatching XSAVE bytes using unsigned decimal
format.  Some versions of clang complain about trying to print an integer
as an unsigned char.

  x86/sev_smoke_test.c:55:51: error: format specifies type 'unsigned char'
                                     but the argument has type 'int' [-Werror,-Wformat]

Fixes: 8c53183dba ("selftests: kvm: add test for transferring FPU state into VMSA")
Link: https://lore.kernel.org/r/20250228233852.3855676-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-03-03 07:45:34 -08:00
Sean Christopherson
62838fa5ea KVM: selftests: Relax assertion on HLT exits if CPU supports Idle HLT
If the CPU supports Idle HLT, which elides HLT VM-Exits if the vCPU has an
unmasked pending IRQ or NMI, relax the xAPIC IPI test's assertion on the
number of HLT exits to only require that the number of exits is less than
or equal to the number of HLT instructions that were executed.  I.e. don't
fail the test if Idle HLT does what it's supposed to do.

Note, unfortunately there's no way to determine if *KVM* supports Idle HLT,
as this_cpu_has() checks raw CPU support, and kvm_cpu_has() checks what can
be exposed to L1, i.e. the latter would check if KVM supports nested Idle
HLT.  But, since the assert is purely bonus coverage, checking for CPU
support is good enough.

Cc: Manali Shukla <Manali.Shukla@amd.com>
Tested-by: Manali Shukla <Manali.Shukla@amd.com>
Link: https://lore.kernel.org/r/20250226231809.3183093-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-28 15:42:28 -08:00
Sean Christopherson
f3513a335e KVM: selftests: Assert that STI blocking isn't set after event injection
Add an L1 (guest) assert to the nested exceptions test to verify that KVM
doesn't put VMRUN in an STI shadow (AMD CPUs bleed the shadow into the
guest's int_state if a #VMEXIT occurs before VMRUN fully completes).

Add a similar assert to the VMX side as well, because why not.

Reviewed-by: Jim Mattson <jmattson@google.com>
Link: https://lore.kernel.org/r/20250224165442.2338294-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-28 09:15:23 -08:00
Sean Christopherson
2428865bf0 KVM: selftests: Add a nested (forced) emulation intercept test for x86
Add a rudimentary test for validating KVM's handling of L1 hypervisor
intercepts during instruction emulation on behalf of L2.  To minimize
complexity and avoid overlap with other tests, only validate KVM's
handling of instructions that L1 wants to intercept, i.e. that generate a
nested VM-Exit.  Full testing of emulation on behalf of L2 is better
achieved by running existing (forced) emulation tests in a VM, (although
on VMX, getting L0 to emulate on #UD requires modifying either L1 KVM to
not intercept #UD, or modifying L0 KVM to prioritize L0's exception
intercepts over L1's intercepts, as is done by KVM for SVM).

Since emulation should never be successful, i.e. L2 always exits to L1,
dynamically generate the L2 code stream instead of adding a helper for
each instruction.  Doing so requires hand coding instruction opcodes, but
makes it significantly easier for the test to compute the expected "next
RIP" and instruction length.

Link: https://lore.kernel.org/r/20250201015518.689704-12-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-24 09:01:07 -08:00
Sean Christopherson
16fc7cb406 KVM: selftests: Add infrastructure for getting vCPU binary stats
Now that the binary stats cache infrastructure is largely scope agnostic,
add support for vCPU-scoped stats.  Like VM stats, open and cache the
stats FD when the vCPU is created so that it's guaranteed to be valid when
vcpu_get_stats() is invoked.

Account for the extra per-vCPU file descriptor in kvm_set_files_rlimit(),
so that tests that create large VMs don't run afoul of resource limits.

To sanity check that the infrastructure actually works, and to get a bit
of bonus coverage, add an assert in x86's xapic_ipi_test to verify that
the number of HLTs executed by the test matches the number of HLT exits
observed by KVM.

Tested-by: Manali Shukla <Manali.Shukla@amd.com>
Link: https://lore.kernel.org/r/20250111005049.1247555-9-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-14 07:02:13 -08:00
Sean Christopherson
b0c3f5df92 KVM: selftests: Macrofy vm_get_stat() to auto-generate stat name string
Turn vm_get_stat() into a macro that generates a string for the stat name,
as opposed to taking a string.  This will allow hardening stat usage in
the future to generate errors on unknown stats at compile time.

No functional change intended.

Link: https://lore.kernel.org/r/20250111005049.1247555-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-14 07:01:55 -08:00
Sean Christopherson
e36454461c KVM: selftests: Add CPUID tests for Hyper-V features that need in-kernel APIC
Add testcases to x86's Hyper-V CPUID test to verify that KVM advertises
support for features that require an in-kernel local APIC appropriately,
i.e. that KVM hides support from the vCPU-scoped ioctl if the VM doesn't
have an in-kernel local APIC.

Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20250118003454.2619573-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-12 08:55:11 -08:00
Sean Christopherson
cd5a0c2f0f KVM: selftests: Manage CPUID array in Hyper-V CPUID test's core helper
Allocate, get, and free the CPUID array in the Hyper-V CPUID test in the
test's core helper, instead of copy+pasting code at each call site.  In
addition to deduplicating a small amount of code, restricting visibility
of the array to a single invocation of the core test prevents "leaking" an
array across test cases.  Passing in @vcpu to the helper will also allow
pivoting on VM-scoped information without needing to pass more booleans,
e.g. to conditionally assert on features that require an in-kernel APIC.

To avoid use-after-free bugs due to overzealous and careless developers,
opportunstically add a comment to explain that the system-scoped helper
caches the Hyper-V CPUID entries, i.e. that the caller is not responsible
for freeing the memory.

Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20250118003454.2619573-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-12 08:53:59 -08:00
Sean Christopherson
0b6db0dc43 KVM: selftests: Mark test_hv_cpuid_e2big() static in Hyper-V CPUID test
Make the Hyper-V CPUID test's local helper test_hv_cpuid_e2big() static,
it's not used outside of the test (and isn't intended to be).

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20250118003454.2619573-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-12 08:53:57 -08:00