linux-kernel - [PATCH v10 28/29] KVM: selftests: Add helpers for safe and safe+forced RDMSR, RDPMC, and XGETBV

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Message-ID: <20240109230250.424295-29-seanjc@google.com>
Date: Tue,  9 Jan 2024 15:02:48 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Kan Liang <kan.liang@...ux.intel.com>, Dapeng Mi <dapeng1.mi@...ux.intel.com>, 
	Jim Mattson <jmattson@...gle.com>, Jinrong Liang <cloudliang@...cent.com>, 
	Aaron Lewis <aaronlewis@...gle.com>, Like Xu <likexu@...cent.com>
Subject: [PATCH v10 28/29] KVM: selftests: Add helpers for safe and
 safe+forced RDMSR, RDPMC, and XGETBV

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@...gle.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