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>
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>
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>
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>
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>
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>
