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SubjectRe: [PATCH] KVM: x86: emulate: correct page fault error code for NoWrite instructions
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Sorry for that. I’ll try to run some few more tests next week.

Nadav

Paolo Bonzini <pbonzini@redhat.com> wrote:

> NoWrite instructions (e.g. cmp or test) never set the "write access"
> bit in the error code, even if one of the operands is treated as a
> destination.
>
> Fixes: c205fb7d7d4f81e46fc577b707ceb9e356af1456
> Cc: Nadav Amit <namit@cs.technion.ac.il>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> arch/x86/kvm/emulate.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index 81dcf7964701..a943bf0c06d0 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -4954,7 +4954,8 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
> rc = segmented_read(ctxt, ctxt->dst.addr.mem,
> &ctxt->dst.val, ctxt->dst.bytes);
> if (rc != X86EMUL_CONTINUE) {
> - if (rc == X86EMUL_PROPAGATE_FAULT &&
> + if (!(ctxt->d & NoWrite) &&
> + rc == X86EMUL_PROPAGATE_FAULT &&
> ctxt->exception.vector == PF_VECTOR)
> ctxt->exception.error_code |= PFERR_WRITE_MASK;
> goto done;
> --
> 1.8.3.1
>
> --
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