@@ -1110,6 +1110,10 @@ void vcpu_init_descriptor_tables(struct kvm_vcpu *vcpu);
void vm_install_exception_handler(struct kvm_vm *vm, int vector,
void (*handler)(struct ex_regs *));
+/* Forced emulation prefix for KVM emulating instruction unconditionally */
+#define KVM_FEP "ud2; .byte 'k', 'v', 'm';"
+#define KVM_FEP_LENGTH 5
+
/* If a toddler were to say "abracadabra". */
#define KVM_EXCEPTION_MAGIC 0xabacadabaULL
@@ -1149,6 +1153,22 @@ void vm_install_exception_handler(struct kvm_vm *vm, int vector,
"mov %%r9b, %[vector]\n\t" \
"mov %%r10, %[error_code]\n\t"
+/*
+ * KVM selftest exception fixup using forced emulation prefix enforces KVM
+ * on emulating instruction unconditionally when kvm.force_emulation_prefix
+ * is enabled.
+ */
+#define KVM_FEP_ASM_SAFE(insn) \
+ "mov $" __stringify(KVM_EXCEPTION_MAGIC) ", %%r9\n\t" \
+ "lea 1f(%%rip), %%r10\n\t" \
+ "lea 2f(%%rip), %%r11\n\t" \
+ KVM_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_OUTPUTS(v, ec) [vector] "=qm"(v), [error_code] "=rm"(ec)
#define KVM_ASM_SAFE_CLOBBERS "r9", "r10", "r11"
Introduce KVM selftest exception fixup using forced emulation prefix to emulate instruction unconditionally when kvm.force_emulation_prefix is enabled. Signed-off-by: Zeng Guang <guang.zeng@intel.com> --- .../selftests/kvm/include/x86_64/processor.h | 20 +++++++++++++++++++ 1 file changed, 20 insertions(+)