linux-kernel - Re: [PATCH v2 1/3] KVM: emulate: Don't inject #GP when emulating RDMPC if CR0.PE=0

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Date:   Fri, 15 Oct 2021 23:20:38 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Wanpeng Li <kernellwp@...il.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        Paolo Bonzini <pbonzini@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>
Subject: Re: [PATCH v2 1/3] KVM: emulate: Don't inject #GP when emulating
 RDMPC if CR0.PE=0

On Sat, Oct 09, 2021, Wanpeng Li wrote:
> From: Wanpeng Li <wanpengli@...cent.com>
> 
> DM mentioned that, RDPMC: 

Heh, missing 'S' in "SDM".

> 
>   IF (((CR4.PCE = 1) or (CPL = 0) or (CR0.PE = 0)) and (ECX indicates a supported counter)) 
>       THEN
>           EAX := counter[31:0];
>           EDX := ZeroExtend(counter[MSCB:32]);
>       ELSE (* ECX is not valid or CR4.PCE is 0 and CPL is 1, 2, or 3 and CR0.PE is 1 *)
>           #GP(0); 
>   FI;
> 
> Let's add the CR0.PE is 1 checking to rdpmc emulate, though this isn't
> strictly necessary since it's impossible for CPL to be >0 if CR0.PE=0.
> 
> Signed-off-by: Wanpeng Li <wanpengli@...cent.com>
> ---

Reviewed-by: Sean Christopherson <seanjc@...gle.com>