KVM: x86 emulator: Add Virtual-8086 mode of emulation
For some instructions CPU behaves differently for real-mode and
virtual 8086. Let emulator know which mode cpu is in, so it will
not poke into vcpu state directly.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 45a4f7c..e4e2df3 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -899,6 +899,7 @@
switch (mode) {
case X86EMUL_MODE_REAL:
+ case X86EMUL_MODE_VM86:
case X86EMUL_MODE_PROT16:
def_op_bytes = def_ad_bytes = 2;
break;
@@ -1525,7 +1526,7 @@
/* syscall is not available in real mode */
if (c->lock_prefix || ctxt->mode == X86EMUL_MODE_REAL
- || !is_protmode(ctxt->vcpu))
+ || ctxt->mode == X86EMUL_MODE_VM86)
return -1;
setup_syscalls_segments(ctxt, &cs, &ss);
@@ -1577,8 +1578,8 @@
if (c->lock_prefix)
return -1;
- /* inject #GP if in real mode or paging is disabled */
- if (ctxt->mode == X86EMUL_MODE_REAL || !is_protmode(ctxt->vcpu)) {
+ /* inject #GP if in real mode */
+ if (ctxt->mode == X86EMUL_MODE_REAL) {
kvm_inject_gp(ctxt->vcpu, 0);
return -1;
}
@@ -1642,8 +1643,9 @@
if (c->lock_prefix)
return -1;
- /* inject #GP if in real mode or paging is disabled */
- if (ctxt->mode == X86EMUL_MODE_REAL || !is_protmode(ctxt->vcpu)) {
+ /* inject #GP if in real mode or Virtual 8086 mode */
+ if (ctxt->mode == X86EMUL_MODE_REAL ||
+ ctxt->mode == X86EMUL_MODE_VM86) {
kvm_inject_gp(ctxt->vcpu, 0);
return -1;
}