@@ -1154,16 +1154,19 @@ void vm_install_exception_handler(struct kvm_vm *vm, int vector,
* r9 = exception vector (non-zero)
* r10 = error code
*/
-#define KVM_ASM_SAFE(insn) \
+#define __KVM_ASM_SAFE(insn, fep) \
"mov $" __stringify(KVM_EXCEPTION_MAGIC) ", %%r9\n\t" \
"lea 1f(%%rip), %%r10\n\t" \
"lea 2f(%%rip), %%r11\n\t" \
- "1: " insn "\n\t" \
+ fep "1: " insn "\n\t" \
"xor %%r9, %%r9\n\t" \
"2:\n\t" \
"mov %%r9b, %[vector]\n\t" \
"mov %%r10, %[error_code]\n\t"
+#define KVM_ASM_SAFE(insn) __KVM_ASM_SAFE(insn, "")
+#define KVM_ASM_SAFE_FEP(insn) __KVM_ASM_SAFE(insn, KVM_FEP)
+
#define KVM_ASM_SAFE_OUTPUTS(v, ec) [vector] "=qm"(v), [error_code] "=rm"(ec)
#define KVM_ASM_SAFE_CLOBBERS "r9", "r10", "r11"
@@ -1190,6 +1193,29 @@ void vm_install_exception_handler(struct kvm_vm *vm, int vector,
vector; \
})
+#define kvm_asm_safe_fep(insn, inputs...) \
+({ \
+ uint64_t ign_error_code; \
+ uint8_t vector; \
+ \
+ asm volatile(KVM_ASM_SAFE(insn) \
+ : KVM_ASM_SAFE_OUTPUTS(vector, ign_error_code) \
+ : inputs \
+ : KVM_ASM_SAFE_CLOBBERS); \
+ vector; \
+})
+
+#define kvm_asm_safe_ec_fep(insn, error_code, inputs...) \
+({ \
+ uint8_t vector; \
+ \
+ asm volatile(KVM_ASM_SAFE_FEP(insn) \
+ : KVM_ASM_SAFE_OUTPUTS(vector, error_code) \
+ : inputs \
+ : KVM_ASM_SAFE_CLOBBERS); \
+ vector; \
+})
+
static inline uint8_t rdmsr_safe(uint32_t msr, uint64_t *val)
{
uint64_t error_code;
Add KVM_ASM_SAFE_FEP() to allow forcing emulation on an instruction that might fault. Note, KVM skips RIP past the FEP prefix before injecting an exception, i.e. the fixup needs to be on the instruction itself. Do not check for FEP support, that is firmly the responsibility of whatever code wants to use KVM_ASM_SAFE_FEP(). Sadly, chaining variadic arguments that contain commas doesn't work, thus the unfortunate amount of copy+paste. Signed-off-by: Sean Christopherson <seanjc@google.com> --- .../selftests/kvm/include/x86_64/processor.h | 30 +++++++++++++++++-- 1 file changed, 28 insertions(+), 2 deletions(-)