From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Chao Gao <chao.gao@intel.com>, Xiaoyao Li <xiaoyao.li@intel.com>
Subject: Re: [PATCH 2/2] KVM: VMX: Drop unnecessary vmx_fb_clear_ctrl_available "cache"
Date: Wed, 7 Jun 2023 13:20:38 -0700 [thread overview]
Message-ID: <20230607202038.5vsgsrt724qhxnjd@desk> (raw)
In-Reply-To: <20230607004311.1420507-3-seanjc@google.com>
On Tue, Jun 06, 2023 at 05:43:10PM -0700, Sean Christopherson wrote:
> Now that KVM snapshots the host's MSR_IA32_ARCH_CAPABILITIES, drop the
> similar snapshot/cache of whether or not KVM is allowed to manipulate
> ARCH_CAPABILITIES.FB_CLEAR_CTRL. The motivation for the cache was
FB_CLEAR_CTRL is a read-only bit, I think you mean
MSR_IA32_MCU_OPT_CTRL.FB_CLEAR_DIS.
> presumably to avoid the RDMSR, e.g. boot_cpu_has_bug() is quite cheap, and
> modifying the vCPU's MSR_IA32_ARCH_CAPABILITIES is an infrequent option
> and a relatively slow path.
>
> Cc: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
LGTM.
Reviewed-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
next prev parent reply other threads:[~2023-06-07 20:21 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-07 0:43 [PATCH 0/2] KVM: x86: Snapshot host MSR_IA32_ARCH_CAPABILITIES Sean Christopherson
2023-06-07 0:43 ` [PATCH 1/2] KVM: x86: Snapshot host's MSR_IA32_ARCH_CAPABILITIES Sean Christopherson
2023-06-08 3:12 ` Xiaoyao Li
2023-06-12 8:34 ` Chao Gao
2023-06-07 0:43 ` [PATCH 2/2] KVM: VMX: Drop unnecessary vmx_fb_clear_ctrl_available "cache" Sean Christopherson
2023-06-07 20:20 ` Pawan Gupta [this message]
2023-06-08 3:15 ` Xiaoyao Li
2023-08-03 0:04 ` [PATCH 0/2] KVM: x86: Snapshot host MSR_IA32_ARCH_CAPABILITIES Sean Christopherson
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