linux-kernel - Re: [PATCH v3 25/25] KVM: nVMX: Use cached host MSR_IA32_VMX

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <018653fac9bd964f65e6fd28fd07da8cb24a61c2.camel@redhat.com>
Date:   Tue, 12 Jul 2022 15:11:50 +0300
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     Vitaly Kuznetsov <vkuznets@...hat.com>, kvm@...r.kernel.org,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>
Cc:     Anirudh Rayabharam <anrayabh@...ux.microsoft.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        linux-hyperv@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 25/25] KVM: nVMX: Use cached host MSR_IA32_VMX_MISC
 value for setting up nested MSR

On Fri, 2022-07-08 at 16:42 +0200, Vitaly Kuznetsov wrote:
> vmcs_config has cased host MSR_IA32_VMX_MISC value, use it for setting
 ^^ typo
> up nested MSR_IA32_VMX_MISC in nested_vmx_setup_ctls_msrs() and avoid the
> redundant rdmsr().
> 
> No (real) functional change intended.
> 
> Reviewed-by: Jim Mattson <jmattson@...gle.com>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
> ---
>  arch/x86/kvm/vmx/nested.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index 3d386c663fac..8026dab71086 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -6754,10 +6754,7 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps)
>                 msrs->secondary_ctls_high |= SECONDARY_EXEC_ENCLS_EXITING;
>  
>         /* miscellaneous data */
> -       rdmsr(MSR_IA32_VMX_MISC,
> -               msrs->misc_low,
> -               msrs->misc_high);
> -       msrs->misc_low &= VMX_MISC_SAVE_EFER_LMA;
> +       msrs->misc_low = (u32)vmcs_conf->misc & VMX_MISC_SAVE_EFER_LMA;
>         msrs->misc_low |=
>                 MSR_IA32_VMX_MISC_VMWRITE_SHADOW_RO_FIELDS |
>                 VMX_MISC_EMULATED_PREEMPTION_TIMER_RATE |

Besides the typo,
Reviewed-by: Maxim Levitsky <mlevitsk@...hat.com>

Best regards,
 Maxim Levitsky