Re: [PATCH 8/8] x86/spec-ctrl: Mitigate the Zen1 DIV leakge

[Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>]

On Wed, Sep 13, 2023 at 09:27:58PM +0100, Andrew Cooper wrote:
> diff --git a/xen/arch/x86/include/asm/cpufeatures.h 
> b/xen/arch/x86/include/asm/cpufeatures.h
> index da0593de8542..724de2e11db4 100644
> --- a/xen/arch/x86/include/asm/cpufeatures.h
> +++ b/xen/arch/x86/include/asm/cpufeatures.h
> @@ -35,7 +35,7 @@ XEN_CPUFEATURE(SC_RSB_HVM,        X86_SYNTH(19)) /* RSB 
> overwrite needed for HVM
>  XEN_CPUFEATURE(XEN_SELFSNOOP,     X86_SYNTH(20)) /* SELFSNOOP gets used by 
> Xen itself */
>  XEN_CPUFEATURE(SC_MSR_IDLE,       X86_SYNTH(21)) /* Clear MSR_SPEC_CTRL on 
> idle */
>  XEN_CPUFEATURE(XEN_LBR,           X86_SYNTH(22)) /* Xen uses 
> MSR_DEBUGCTL.LBR */
> -/* Bits 23 unused. */
> +XEN_CPUFEATURE(SC_DIV,            X86_SYNTH(25)) /* DIV scrub needed */

s/25/23/

>  XEN_CPUFEATURE(SC_RSB_IDLE,       X86_SYNTH(24)) /* RSB overwrite needed for 
> idle. */
>  XEN_CPUFEATURE(SC_VERW_IDLE,      X86_SYNTH(25)) /* VERW used by Xen for 
> idle */
>  XEN_CPUFEATURE(XEN_SHSTK,         X86_SYNTH(26)) /* Xen uses CET Shadow 
> Stacks */

-- 
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab

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