[kvm-unit-tests PATCH v2 1/2] x86: Add FEP support on read/write register instructions

[Mingwei Zhang <mizhang@google.com>]

Add FEP support on read/write register instructions to enable testing rdmsr
and wrmsr when force emulation is turned on.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
---
 lib/x86/desc.h      | 30 ++++++++++++++++++++++++------
 lib/x86/processor.h | 18 ++++++++++++++----
 2 files changed, 38 insertions(+), 10 deletions(-)

diff --git a/lib/x86/desc.h b/lib/x86/desc.h
index 7778a0f8..92c45a48 100644
--- a/lib/x86/desc.h
+++ b/lib/x86/desc.h
@@ -272,9 +272,9 @@ extern gdt_entry_t *get_tss_descr(void);
 extern unsigned long get_gdt_entry_base(gdt_entry_t *entry);
 extern unsigned long get_gdt_entry_limit(gdt_entry_t *entry);
 
-#define asm_safe(insn, inputs...)					\
+#define __asm_safe(fep, insn, inputs...)				\
 ({									\
-	asm volatile(ASM_TRY("1f")					\
+	asm volatile(__ASM_TRY(fep, "1f")				\
 		     insn "\n\t"					\
 		     "1:\n\t"						\
 		     :							\
@@ -283,9 +283,15 @@ extern unsigned long get_gdt_entry_limit(gdt_entry_t *entry);
 	exception_vector();						\
 })
 
-#define asm_safe_out1(insn, output, inputs...)				\
+#define asm_safe(insn, inputs...)					\
+	__asm_safe("", insn, inputs)
+
+#define asm_fep_safe(insn, output, inputs...)				\
+	__asm_safe_out1(KVM_FEP, insn, output, inputs)
+
+#define __asm_safe_out1(fep, insn, output, inputs...)			\
 ({									\
-	asm volatile(ASM_TRY("1f")					\
+	asm volatile(__ASM_TRY(fep, "1f")				\
 		     insn "\n\t"					\
 		     "1:\n\t"						\
 		     : output						\
@@ -294,9 +300,15 @@ extern unsigned long get_gdt_entry_limit(gdt_entry_t *entry);
 	exception_vector();						\
 })
 
-#define asm_safe_out2(insn, output1, output2, inputs...)		\
+#define asm_safe_out1(insn, output, inputs...)				\
+	__asm_safe_out1("", insn, output, inputs)
+
+#define asm_fep_safe_out1(insn, output, inputs...)			\
+	__asm_safe_out1(KVM_FEP, insn, output, inputs)
+
+#define __asm_safe_out2(fep, insn, output1, output2, inputs...)		\
 ({									\
-	asm volatile(ASM_TRY("1f")					\
+	asm volatile(__ASM_TRY(fep, "1f")				\
 		     insn "\n\t"					\
 		     "1:\n\t"						\
 		     : output1, output2					\
@@ -305,6 +317,12 @@ extern unsigned long get_gdt_entry_limit(gdt_entry_t *entry);
 	exception_vector();						\
 })
 
+#define asm_safe_out2(fep, insn, output1, output2, inputs...)		\
+	__asm_safe_out2("", insn, output1, output2, inputs)
+
+#define asm_fep_safe_out2(insn, output1, output2, inputs...)		\
+	__asm_safe_out2(KVM_FEP, insn, output1, output2, inputs)
+
 #define __asm_safe_report(want, insn, inputs...)			\
 do {									\
 	int vector = asm_safe(insn, inputs);				\
diff --git a/lib/x86/processor.h b/lib/x86/processor.h
index 44f4fd1e..d20496c0 100644
--- a/lib/x86/processor.h
+++ b/lib/x86/processor.h
@@ -430,12 +430,12 @@ static inline void wrmsr(u32 index, u64 val)
 	asm volatile ("wrmsr" : : "a"(a), "d"(d), "c"(index) : "memory");
 }
 
-#define rdreg64_safe(insn, index, val)					\
+#define __rdreg64_safe(fep, insn, index, val)				\
 ({									\
 	uint32_t a, d;							\
 	int vector;							\
 									\
-	vector = asm_safe_out2(insn, "=a"(a), "=d"(d), "c"(index));	\
+	vector = __asm_safe_out2(fep, insn, "=a"(a), "=d"(d), "c"(index));\
 									\
 	if (vector)							\
 		*(val) = 0;						\
@@ -444,13 +444,18 @@ static inline void wrmsr(u32 index, u64 val)
 	vector;								\
 })
 
-#define wrreg64_safe(insn, index, val)					\
+#define rdreg64_safe(insn, index, val)					\
+	__rdreg64_safe("", insn, index, val)
+
+#define __wrreg64_safe(fep, insn, index, val)				\
 ({									\
 	uint32_t eax = (val), edx = (val) >> 32;			\
 									\
-	asm_safe(insn, "a" (eax), "d" (edx), "c" (index));		\
+	__asm_safe(fep, insn, "a" (eax), "d" (edx), "c" (index));	\
 })
 
+#define wrreg64_safe(insn, index, val)					\
+	__wrreg64_safe("", insn, index, val)
 
 static inline int rdmsr_safe(u32 index, uint64_t *val)
 {
@@ -462,6 +467,11 @@ static inline int wrmsr_safe(u32 index, u64 val)
 	return wrreg64_safe("wrmsr", index, val);
 }
 
+static inline int wrmsr_fep_safe(u32 index, u64 val)
+{
+	return __wrreg64_safe(KVM_FEP, "wrmsr", index, val);
+}
+
 static inline int rdpmc_safe(u32 index, uint64_t *val)
 {
 	return rdreg64_safe("rdpmc", index, val);
-- 
2.44.0.683.g7961c838ac-goog