On Sun, Aug 15, 2010 at 10:32 AM, Gleb Natapov <gleb@xxxxxxxxxx> wrote:
> On Sat, Aug 14, 2010 at 06:51:34PM +0300, Mohammed Gamal wrote:
>> If emulation fails due to the instruction being unemulated. Return immediately
>> instead of restarting the instruction and infinitely trying to execute it.
>>
> This is already handled correctly as far as I can see. Sometimes
> instruction should be retried and reexecute_instruction() checks
> for that case. If instruction emulation fails in big real mode
> re-executing instruction will be useless though, so what should be done
> is to make reexecute_instruction() return false if vcpu is in big real
> mode and cpu relies on emulation to handle it.
We don't have a separate mode for big real mode. The emulation modes
we have are real and vm86
>
>> Signed-off-by: Mohammed Gamal <m.gamal005@xxxxxxxxx>
>> ---
>> arch/x86/kvm/x86.c | 6 ++++++
>> 1 files changed, 6 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>> index 416aa0e..a31db44 100644
>> --- a/arch/x86/kvm/x86.c
>> +++ b/arch/x86/kvm/x86.c
>> @@ -4036,6 +4036,9 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
>> }
>>
>> ++vcpu->stat.insn_emulation;
>> + if (r == X86EMUL_UNHANDLEABLE)
>> + return handle_emulation_failure(vcpu);
>> +
>> if (r) {
>> if (reexecute_instruction(vcpu, cr2))
>> return EMULATE_DONE;
>> @@ -4057,6 +4060,9 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
>> restart:
>> r = x86_emulate_insn(&vcpu->arch.emulate_ctxt);
>>
>> + if (r == X86EMUL_UNHANDLEABLE)
>> + return handle_emulation_failure(vcpu);
>> +
>> if (r) { /* emulation failed */
>> if (reexecute_instruction(vcpu, cr2))
>> return EMULATE_DONE;
>> --
>> 1.7.0.4
>>
>> --
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>
> --
> Gleb.
>
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