KVM: selftests: Fix reserved value WRMSR testcase for multi-feature MSRs

When determining whether or not a WRMSR with reserved bits will #GP or
succeed due to the WRMSR not existing per the guest virtual CPU model,
expect failure if and only if _all_ features associated with the MSR are
unsupported.  Checking only the primary feature results in false failures
when running on AMD and Hygon CPUs with only one of RDPID or RDTSCP, as
AMD/Hygon CPUs ignore MSR_TSC_AUX[63:32], i.e. don't treat the bits as
reserved, and so #GP only if the MSR is unsupported.

Fixes: 9c38ddb3df94 ("KVM: selftests: Add an MSR test to exercise guest/host and read/write")
Reported-by: Zhiquan Li <zhiquan_li@163.com>
Closes: https://lore.kernel.org/all/20260209041305.64906-6-zhiquan_li@163.com
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260212103841.171459-5-zhiquan_li@163.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/tools/testing/selftests/kvm/x86/msrs_test.c b/tools/testing/selftests/kvm/x86/msrs_test.c
index 4c97444fdefec07345fd1ce514af8c26ead7753b..f7e39bf887ad31dba0176a8f6f2fd1aa0aba96f8 100644 (file)
--- a/tools/testing/selftests/kvm/x86/msrs_test.c
+++ b/tools/testing/selftests/kvm/x86/msrs_test.c
@@ -175,7 +175,7 @@ void guest_test_reserved_val(const struct kvm_msr *msr)
         * If the CPU will truncate the written value (e.g. SYSENTER on AMD),
         * expect success and a truncated value, not #GP.
         */
-       if (!this_cpu_has(msr->feature) ||
+       if ((!this_cpu_has(msr->feature) && !this_cpu_has(msr->feature2)) ||
            msr->rsvd_val == fixup_rdmsr_val(msr->index, msr->rsvd_val)) {
                u8 vec = wrmsr_safe(msr->index, msr->rsvd_val);