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@xxxxxxxxx> --- .../selftests/kvm/include/x86_64/processor.h | 20 +++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h index 2534bdf8aa71..a1645508affc 100644 --- a/tools/testing/selftests/kvm/include/x86_64/processor.h +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h @@ -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" -- 2.21.3
