Provide the result of RDMSR from rdmsr_safe() so that it can be used by
tests that are unsure whether or not RDMSR will fault, but want the value
if it doesn't fault.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
lib/x86/processor.h | 9 +++++++--
x86/msr.c | 3 ++-
2 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/lib/x86/processor.h b/lib/x86/processor.h
index bc6c8d94..82f8df58 100644
--- a/lib/x86/processor.h
+++ b/lib/x86/processor.h
@@ -360,12 +360,17 @@ static inline void wrmsr(u32 index, u64 val)
asm volatile ("wrmsr" : : "a"(a), "d"(d), "c"(index) : "memory");
}
-static inline int rdmsr_safe(u32 index)
+static inline int rdmsr_safe(u32 index, uint64_t *val)
{
+ uint32_t a, d;
+
asm volatile (ASM_TRY("1f")
"rdmsr\n\t"
"1:"
- : : "c"(index) : "memory", "eax", "edx");
+ : "=a"(a), "=d"(d)
+ : "c"(index) : "memory");
+
+ *val = (uint64_t)a | ((uint64_t)d << 32);
return exception_vector();
}
diff --git a/x86/msr.c b/x86/msr.c
index eaca19ed..ee1d3984 100644
--- a/x86/msr.c
+++ b/x86/msr.c
@@ -81,7 +81,8 @@ static void test_wrmsr_fault(struct msr_info *msr, unsigned long long val)
static void test_rdmsr_fault(struct msr_info *msr)
{
- unsigned char vector = rdmsr_safe(msr->index);
+ uint64_t ignored;
+ unsigned char vector = rdmsr_safe(msr->index, &ignored);
report(vector == GP_VECTOR,
"Expected #GP on RDSMR(%s), got vector %d", msr->name, vector);
--
2.36.1.255.ge46751e96f-goog
