Assert that KVM provides "read what you wrote" semantics for all "durable"
MSRs (for lack of a better name). The extra coverage is cheap from a
runtime performance perspective, and verifying the behavior in the common
helper avoids gratuitous copy+paste in individual tests.
Note, this affects all tests that set MSRs from userspace!
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
.../selftests/kvm/include/x86_64/processor.h | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index 26c8e202a956..52260f6c2465 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -945,12 +945,27 @@ do { \
} \
} while (0)
+/*
+ * Returns true if KVM should return the last written value when reading an MSR
+ * from userspace, e.g. the MSR isn't a command MSR, doesn't emulate state that
+ * is changing, etc. This is NOT an exhaustive list! The intent is to filter
+ * out MSRs that are not durable _and_ that a selftest wants to write.
+ */
+static inline bool is_durable_msr(uint32_t msr)
+{
+ return msr != MSR_IA32_TSC;
+}
+
#define vcpu_set_msr(vcpu, msr, val) \
do { \
- uint64_t v = val; \
+ uint64_t r, v = val; \
\
TEST_ASSERT_MSR(_vcpu_set_msr(vcpu, msr, v) == 1, \
"KVM_SET_MSRS failed on %s, value = 0x%lx", msr, #msr, v); \
+ if (!is_durable_msr(msr)) \
+ break; \
+ r = vcpu_get_msr(vcpu, msr); \
+ TEST_ASSERT_MSR(r == v, "Set %s to '0x%lx', got back '0x%lx'", msr, #msr, v, r);\
} while (0)
void kvm_get_cpu_address_width(unsigned int *pa_bits, unsigned int *va_bits);
--
2.40.0.rc1.284.g88254d51c5-goog
