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-rw-r--r--arch/x86/kvm/svm.c2
-rw-r--r--arch/x86/kvm/vmx.c2
-rw-r--r--arch/x86/kvm/x86.c18
-rw-r--r--include/asm-x86/kvm_host.h4
4 files changed, 20 insertions, 6 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 33f77b044c5..de755cb1431 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -942,7 +942,7 @@ static int ud_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
int er;
- er = emulate_instruction(&svm->vcpu, kvm_run, 0, 0, 0);
+ er = emulate_instruction(&svm->vcpu, kvm_run, 0, 0, EMULTYPE_TRAP_UD);
if (er != EMULATE_DONE)
kvm_queue_exception(&svm->vcpu, UD_VECTOR);
return 1;
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 3d251f894a8..ad36447e696 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1863,7 +1863,7 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
}
if (is_invalid_opcode(intr_info)) {
- er = emulate_instruction(vcpu, kvm_run, 0, 0, 0);
+ er = emulate_instruction(vcpu, kvm_run, 0, 0, EMULTYPE_TRAP_UD);
if (er != EMULATE_DONE)
kvm_queue_exception(vcpu, UD_VECTOR);
return 1;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e3b3141db13..8a90403272e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1840,9 +1840,10 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
struct kvm_run *run,
unsigned long cr2,
u16 error_code,
- int no_decode)
+ int emulation_type)
{
int r;
+ struct decode_cache *c;
vcpu->arch.mmio_fault_cr2 = cr2;
kvm_x86_ops->cache_regs(vcpu);
@@ -1850,7 +1851,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
vcpu->mmio_is_write = 0;
vcpu->arch.pio.string = 0;
- if (!no_decode) {
+ if (!(emulation_type & EMULTYPE_NO_DECODE)) {
int cs_db, cs_l;
kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l);
@@ -1884,6 +1885,16 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
get_segment_base(vcpu, VCPU_SREG_FS);
r = x86_decode_insn(&vcpu->arch.emulate_ctxt, &emulate_ops);
+
+ /* Reject the instructions other than VMCALL/VMMCALL when
+ * try to emulate invalid opcode */
+ c = &vcpu->arch.emulate_ctxt.decode;
+ if ((emulation_type & EMULTYPE_TRAP_UD) &&
+ (!(c->twobyte && c->b == 0x01 &&
+ (c->modrm_reg == 0 || c->modrm_reg == 3) &&
+ c->modrm_mod == 3 && c->modrm_rm == 1)))
+ return EMULATE_FAIL;
+
++vcpu->stat.insn_emulation;
if (r) {
++vcpu->stat.insn_emulation_fail;
@@ -2640,7 +2651,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
vcpu->mmio_read_completed = 1;
vcpu->mmio_needed = 0;
r = emulate_instruction(vcpu, kvm_run,
- vcpu->arch.mmio_fault_cr2, 0, 1);
+ vcpu->arch.mmio_fault_cr2, 0,
+ EMULTYPE_NO_DECODE);
if (r == EMULATE_DO_MMIO) {
/*
* Read-modify-write. Back to userspace.
diff --git a/include/asm-x86/kvm_host.h b/include/asm-x86/kvm_host.h
index 20597bc1674..4702b04b979 100644
--- a/include/asm-x86/kvm_host.h
+++ b/include/asm-x86/kvm_host.h
@@ -415,8 +415,10 @@ enum emulation_result {
EMULATE_FAIL, /* can't emulate this instruction */
};
+#define EMULTYPE_NO_DECODE (1 << 0)
+#define EMULTYPE_TRAP_UD (1 << 1)
int emulate_instruction(struct kvm_vcpu *vcpu, struct kvm_run *run,
- unsigned long cr2, u16 error_code, int no_decode);
+ unsigned long cr2, u16 error_code, int emulation_type);
void kvm_report_emulation_failure(struct kvm_vcpu *cvpu, const char *context);
void realmode_lgdt(struct kvm_vcpu *vcpu, u16 size, unsigned long address);
void realmode_lidt(struct kvm_vcpu *vcpu, u16 size, unsigned long address);