linux-kernel - Re: [PATCH] KVM: Emulate multibyte NOP

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Message-ID: <20130603082108.GB4725@redhat.com>
Date:	Mon, 3 Jun 2013 11:21:08 +0300
From:	Gleb Natapov <gleb@...hat.com>
To:	Paolo Bonzini <pbonzini@...hat.com>
Cc:	linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
	stable@...r.kernel.org
Subject: Re: [PATCH] KVM: Emulate multibyte NOP

On Thu, May 30, 2013 at 01:22:39PM +0200, Paolo Bonzini wrote:
> This is encountered when booting RHEL5.9 64-bit.  There is another bug
> after this one that is not a simple emulation failure, but this one lets
> the boot proceed a bit.
> 
> Cc: <stable@...r.kernel.org> # 3.9
> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Applied to master, thanks.

> ---
>  arch/x86/kvm/emulate.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index 48e6abd..aa68106 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -3987,7 +3987,8 @@ static const struct opcode twobyte_table[256] = {
>  	DI(ImplicitOps | Priv, invd), DI(ImplicitOps | Priv, wbinvd), N, N,
>  	N, D(ImplicitOps | ModRM), N, N,
>  	/* 0x10 - 0x1F */
> -	N, N, N, N, N, N, N, N, D(ImplicitOps | ModRM), N, N, N, N, N, N, N,
> +	N, N, N, N, N, N, N, N,
> +	D(ImplicitOps | ModRM), N, N, N, N, N, N, D(ImplicitOps | ModRM),
>  	/* 0x20 - 0x2F */
>  	DIP(ModRM | DstMem | Priv | Op3264, cr_read, check_cr_read),
>  	DIP(ModRM | DstMem | Priv | Op3264, dr_read, check_dr_read),
> @@ -4822,6 +4823,7 @@ twobyte_insn:
>  	case 0x08:		/* invd */
>  	case 0x0d:		/* GrpP (prefetch) */
>  	case 0x18:		/* Grp16 (prefetch/nop) */
> +	case 0x1f:		/* nop */
>  		break;
>  	case 0x20: /* mov cr, reg */
>  		ctxt->dst.val = ops->get_cr(ctxt, ctxt->modrm_reg);
> -- 
> 1.8.1.4

--
			Gleb.
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