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KVM: x86 emulator: fix in/out emulation.

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in/out emulation is broken now. The breakage is different depending
on where IO device resides. If it is in userspace emulator reports
emulation failure since it incorrectly interprets kvm_emulate_pio()
return value. If IO device is in the kernel emulation of 'in' will do
nothing since kvm_emulate_pio() stores result directly into vcpu
registers, so emulator will overwrite result of emulation during
commit of shadowed register.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Gleb Natapov
2010-03-18 15:20:23 +02:00
committed by Avi Kivity
parent d9271123a4
commit cf8f70bfe3
6 changed files with 181 additions and 136 deletions
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20
arch/x86/kvm/svm.c
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@@ -1494,29 +1494,23 @@ static int shutdown_interception(struct vcpu_svm *svm)
static int io_interception(struct vcpu_svm *svm)
{
struct kvm_vcpu *vcpu = &svm->vcpu;
u32 io_info = svm->vmcb->control.exit_info_1; /* address size bug? */
int size, in, string;
unsigned port;
++svm->vcpu.stat.io_exits;
svm->next_rip = svm->vmcb->control.exit_info_2;
string = (io_info & SVM_IOIO_STR_MASK) != 0;
if (string) {
if (emulate_instruction(&svm->vcpu,
0, 0, 0) == EMULATE_DO_MMIO)
return 0;
return 1;
}
in = (io_info & SVM_IOIO_TYPE_MASK) != 0;
if (string || in)
return !(emulate_instruction(vcpu, 0, 0, 0) == EMULATE_DO_MMIO);
port = io_info >> 16;
size = (io_info & SVM_IOIO_SIZE_MASK) >> SVM_IOIO_SIZE_SHIFT;
svm->next_rip = svm->vmcb->control.exit_info_2;
skip_emulated_instruction(&svm->vcpu);
return kvm_emulate_pio(&svm->vcpu, in, size, port);
return kvm_fast_pio_out(vcpu, size, port);
}
static int nmi_interception(struct vcpu_svm *svm)