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.
> 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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