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Subject[PATCH v10 28/29] KVM: selftests: Add helpers for safe and safe+forced RDMSR, RDPMC, and XGETBV
From
Add helpers for safe and safe-with-forced-emulations versions of RDMSR,
RDPMC, and XGETBV. Use macro shenanigans to eliminate the rather large
amount of boilerplate needed to get values in and out of registers.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
.../selftests/kvm/include/x86_64/processor.h | 40 +++++++++++++------
1 file changed, 27 insertions(+), 13 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index fe891424ff55..abac816f6594 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -1216,21 +1216,35 @@ void vm_install_exception_handler(struct kvm_vm *vm, int vector,
vector; \
})

-static inline uint8_t rdmsr_safe(uint32_t msr, uint64_t *val)
-{
- uint64_t error_code;
- uint8_t vector;
- uint32_t a, d;
-
- asm volatile(KVM_ASM_SAFE("rdmsr")
- : "=a"(a), "=d"(d), KVM_ASM_SAFE_OUTPUTS(vector, error_code)
- : "c"(msr)
- : KVM_ASM_SAFE_CLOBBERS);
-
- *val = (uint64_t)a | ((uint64_t)d << 32);
- return vector;
+#define BUILD_READ_U64_SAFE_HELPER(insn, _fep, _FEP) \
+static inline uint8_t insn##_safe ##_fep(uint32_t idx, uint64_t *val) \
+{ \
+ uint64_t error_code; \
+ uint8_t vector; \
+ uint32_t a, d; \
+ \
+ asm volatile(KVM_ASM_SAFE##_FEP(#insn) \
+ : "=a"(a), "=d"(d), \
+ KVM_ASM_SAFE_OUTPUTS(vector, error_code) \
+ : "c"(idx) \
+ : KVM_ASM_SAFE_CLOBBERS); \
+ \
+ *val = (uint64_t)a | ((uint64_t)d << 32); \
+ return vector; \
}

+/*
+ * Generate {insn}_safe() and {insn}_safe_fep() helpers for instructions that
+ * use ECX as in input index, and EDX:EAX as a 64-bit output.
+ */
+#define BUILD_READ_U64_SAFE_HELPERS(insn) \
+ BUILD_READ_U64_SAFE_HELPER(insn, , ) \
+ BUILD_READ_U64_SAFE_HELPER(insn, _fep, _FEP) \
+
+BUILD_READ_U64_SAFE_HELPERS(rdmsr)
+BUILD_READ_U64_SAFE_HELPERS(rdpmc)
+BUILD_READ_U64_SAFE_HELPERS(xgetbv)
+
static inline uint8_t wrmsr_safe(uint32_t msr, uint64_t val)
{
return kvm_asm_safe("wrmsr", "a"(val & -1u), "d"(val >> 32), "c"(msr));
--
2.43.0.472.g3155946c3a-goog

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