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From: Sean Christopherson <seanjc@google.com>
To: Doug Covelli <doug.covelli@broadcom.com>
Cc: David Woodhouse <dwmw2@infradead.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	 Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	 Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org,  "H. Peter Anvin" <hpa@zytor.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	kvm@vger.kernel.org,  linux-kernel@vger.kernel.org,
	graf@amazon.de,  Ajay Kaher <ajay.kaher@broadcom.com>,
	Alexey Makhalov <alexey.makhalov@broadcom.com>,
	 Colin Percival <cperciva@tarsnap.com>,
	Zack Rusin <zack.rusin@broadcom.com>
Subject: Re: [PATCH v2 2/3] KVM: x86: Provide TSC frequency in "generic" timing infomation CPUID leaf
Date: Tue, 16 Dec 2025 14:59:24 -0800	[thread overview]
Message-ID: <aUHkTBzRqqvsG0LG@google.com> (raw)
In-Reply-To: <CADH9ctCEVJCC+_bZwDETmePhgfVy+jJvSb4Jz6bGLdmL9RSmUA@mail.gmail.com>

On Tue, Dec 16, 2025, Doug Covelli wrote:
> On Tue, Dec 16, 2025 at 3:27 PM Sean Christopherson <seanjc@google.com> wrote:
> >
> > +Doug and Zach
> >
> > VMware folks, TL;DR question for you:
> >
> >   Does VMware report TSC and APIC bus frequency in CPUID 0x40000010.{EAX,EBX},
> >   or at the very least pinky swear not to use those outputs for anything else?
> 
> Yes, all 32-bits of 0x40000010.EAX is for TSC frequency and all
> 32-bits of 0x40000010.EBX is for APIC bus frequency.

Nice, thanks much for the confirmation and quick response!

  reply	other threads:[~2025-12-16 22:59 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-16 10:09 [PATCH v2 0/3] Support "generic" CPUID timing leaf as KVM guest and host David Woodhouse
2025-08-16 10:10 ` [PATCH v2 1/3] KVM: x86: Restore caching of KVM CPUID base David Woodhouse
2025-08-16 10:10 ` [PATCH v2 2/3] KVM: x86: Provide TSC frequency in "generic" timing infomation CPUID leaf David Woodhouse
2025-12-16 20:27   ` Sean Christopherson
2025-12-16 21:10     ` Doug Covelli
2025-12-16 22:59       ` Sean Christopherson [this message]
2025-08-16 10:10 ` [PATCH v2 3/3] x86/kvm: Obtain TSC frequency from CPUID if present David Woodhouse
2025-08-21 16:26 ` [PATCH v2 0/3] Support "generic" CPUID timing leaf as KVM guest and host Sean Christopherson
2025-08-21 17:37   ` David Woodhouse
2025-08-21 19:27     ` Sean Christopherson
2025-08-21 20:42       ` David Woodhouse
2025-08-21 20:48         ` Sean Christopherson
2025-08-21 21:10           ` David Woodhouse
2025-08-22  1:57             ` Colin Percival
2025-08-26 19:30               ` Sean Christopherson
2025-08-27  9:30                 ` David Woodhouse
2025-08-28 23:40                   ` Sean Christopherson
2025-08-29  9:50                     ` David Woodhouse
2025-08-29 11:08                       ` Durrant, Paul
2025-08-29 11:19                         ` David Woodhouse
2025-08-29 20:36                           ` Sean Christopherson
2025-09-02  8:31                             ` David Woodhouse
2025-09-02 17:49                               ` Sean Christopherson
2025-09-02 18:23                                 ` David Woodhouse
2025-09-04 11:59                                   ` Sean Christopherson
2025-09-04 12:14                                     ` David Woodhouse
2025-09-04 13:25                                       ` Sean Christopherson
2025-09-04 13:51                                         ` David Woodhouse
2025-09-05  7:57                                           ` Sean Christopherson

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