From: Sean Christopherson <seanjc@google.com>
To: Paul Durrant <pdurrant@amazon.com>
Cc: x86@kernel.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org,
David Woodhouse <dwmw2@infradead.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH v4] KVM: x86/xen: Update Xen CPUID Leaf 4 (tsc info) sub-leaves, if present
Date: Mon, 27 Jun 2022 15:19:15 +0000 [thread overview]
Message-ID: <YrnKc6RoqDM/At3T@google.com> (raw)
In-Reply-To: <20220622151728.13622-1-pdurrant@amazon.com>
On Wed, Jun 22, 2022, Paul Durrant wrote:
> The scaling information in subleaf 1 should match the values set by KVM in
> the 'vcpu_info' sub-structure 'time_info' (a.k.a. pvclock_vcpu_time_info)
> which is shared with the guest, but is not directly available to the VMM.
> The offset values are not set since a TSC offset is already applied.
> The TSC frequency should also be set in sub-leaf 2.
>
> Cache pointers to the sub-leaves when CPUID is updated by the VMM and
> populate the relevant information prior to entering the guest.
All of my comments about the code still apply.
https://lore.kernel.org/all/YrMqtHzNSean+qkh@google.com
> Signed-off-by: Paul Durrant <pdurrant@amazon.com>
> ---
> Cc: David Woodhouse <dwmw2@infradead.org>
Cc: can go in the changelog, it's helpful info to carry with the commit as it
documents who was made aware of the patch, e.g. show who may have had a cance to
object/review.
>
> v2:
> - Make sure sub-leaf pointers are NULLed if the time leaf is removed
>
> v3:
> - Add leaf limit check in kvm_xen_set_cpuid()
>
> v4:
> - Update commit comment
Please start with the most recent verison and work backardwards, that way reviewers
can quickly see the delta for _this_ version. I.e.
v4:
v3:
v2:
v1:
next prev parent reply other threads:[~2022-06-27 15:20 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-22 15:17 [PATCH v4] KVM: x86/xen: Update Xen CPUID Leaf 4 (tsc info) sub-leaves, if present Paul Durrant
2022-06-27 15:19 ` Sean Christopherson [this message]
2022-06-27 15:23 ` Durrant, Paul
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