From: Sean Christopherson <seanjc@google.com>
To: Lei Wang <lei4.wang@intel.com>
Cc: pbonzini@redhat.com, vkuznets@redhat.com, wanpengli@tencent.com,
jmattson@google.com, joro@8bytes.org, chenyi.qiang@intel.com,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 2/8] KVM: VMX: Add proper cache tracking for PKRS
Date: Tue, 24 May 2022 21:00:42 +0000 [thread overview]
Message-ID: <Yo1Hemue8+l5CPIT@google.com> (raw)
In-Reply-To: <20220424101557.134102-3-lei4.wang@intel.com>
On Sun, Apr 24, 2022, Lei Wang wrote:
> From: Chenyi Qiang <chenyi.qiang@intel.com>
>
> Add PKRS caching into the standard register caching mechanism in order
> to take advantage of the availability checks provided by regs_avail.
>
> This is because vcpu->arch.pkrs will be rarely acceesed by KVM, only in
> the case of host userspace MSR reads and GVA->GPA translation in
> following patches. It is unnecessary to keep it up-to-date at all times.
>
> It also should be noted that the potential benefits of this caching are
> tenuous because the MSR read is not a hot path. it's nice-to-have so that
> we don't hesitate to rip it out in the future if there's a strong reason
> to drop the caching.
The patch looks fine, but this needs to be moved to the end of the series.
Definitely after "KVM: VMX: Expose PKS to guest", and maybe even after "KVM: VMX:
Enable PKS for nested VM".
If there's a bug with the caching logic, I want to be able to bisect to that. By
implementing caching before any of the other PKS support, a bug in either the
caching or the virtualization will bisect to the PKS virtualization
next prev parent reply other threads:[~2022-05-24 21:00 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-24 10:15 [PATCH v7 0/8] KVM: PKS Virtualization support Lei Wang
2022-04-24 10:15 ` [PATCH v7 1/8] KVM: VMX: Introduce PKS VMCS fields Lei Wang
2022-05-24 20:55 ` Sean Christopherson
2022-05-27 1:55 ` Wang, Lei
2022-04-24 10:15 ` [PATCH v7 2/8] KVM: VMX: Add proper cache tracking for PKRS Lei Wang
2022-05-24 21:00 ` Sean Christopherson [this message]
2022-05-27 2:16 ` Wang, Lei
2022-04-24 10:15 ` [PATCH v7 3/8] KVM: X86: Expose IA32_PKRS MSR Lei Wang
2022-05-24 22:11 ` Sean Christopherson
2022-05-27 9:21 ` Wang, Lei
2022-04-24 10:15 ` [PATCH v7 4/8] KVM: MMU: Rename the pkru to pkr Lei Wang
2022-04-24 10:15 ` [PATCH v7 5/8] KVM: MMU: Add helper function to get pkr bits Lei Wang
2022-05-24 23:21 ` Sean Christopherson
2022-05-27 9:28 ` Wang, Lei
2022-04-24 10:15 ` [PATCH v7 6/8] KVM: MMU: Add support for PKS emulation Lei Wang
2022-05-24 23:28 ` Sean Christopherson
2022-05-27 9:40 ` Wang, Lei
2022-04-24 10:15 ` [PATCH v7 7/8] KVM: VMX: Expose PKS to guest Lei Wang
2022-05-24 23:34 ` Sean Christopherson
2022-05-27 9:42 ` Wang, Lei
2022-04-24 10:15 ` [PATCH v7 8/8] KVM: VMX: Enable PKS for nested VM Lei Wang
2022-05-20 1:24 ` Sean Christopherson
2022-05-27 9:55 ` Wang, Lei
2022-05-06 7:32 ` [PATCH v7 0/8] KVM: PKS Virtualization support Wang, Lei
2025-11-10 16:29 ` The current status of PKS virtualization Ruihan Li
2025-11-10 20:44 ` Paolo Bonzini
2025-11-11 1:14 ` Ruihan Li
2025-11-11 5:40 ` Chenyi Qiang
2025-11-11 14:24 ` Ruihan Li
2025-11-12 1:06 ` Chenyi Qiang
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