linux-kernel - Re: [PATCH v2 0/2] Improve KVM_SET_TSC

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Message-ID: <e1151fff87e0f0f26462fed509a41916dd6ba8e7.camel@intel.com>
Date: Tue, 15 Jul 2025 00:54:00 +0000
From: "Huang, Kai" <kai.huang@...el.com>
To: "pbonzini@...hat.com" <pbonzini@...hat.com>, "seanjc@...gle.com"
	<seanjc@...gle.com>
CC: "Gao, Chao" <chao.gao@...el.com>, "Edgecombe, Rick P"
	<rick.p.edgecombe@...el.com>, "bp@...en8.de" <bp@...en8.de>, "Li, Xiaoyao"
	<xiaoyao.li@...el.com>, "nikunj@....com" <nikunj@....com>,
	"thomas.lendacky@....com" <thomas.lendacky@....com>, "kvm@...r.kernel.org"
	<kvm@...r.kernel.org>, "Yamahata, Isaku" <isaku.yamahata@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 0/2] Improve KVM_SET_TSC_KHZ handling for CoCo VMs

On Mon, 2025-07-14 at 17:23 -0700, Sean Christopherson wrote:
> On Mon, 14 Jul 2025 10:20:18 +1200, Kai Huang wrote:
> > This series follows Sean's suggestions [1][2] to:
> > 
> >  - Reject vCPU scope KVM_SET_TSC_KHZ ioctl for TSC protected vCPU
> >  - Reject VM scope KVM_SET_TSC_KHZ ioctl when vCPUs have been created
> > 
> > .. in the discussion of SEV-SNP Secure TSC support series.
> > 
> > [...]
> 
> Applied patch 2 to kvm-x86 fixes, with a tweaked changelog to call out that
> TDX support hasn't yet been released, i.e. that there is no established ABI
> to break.
> 
> Applied patch 1 to kvm-x86 misc, with tweaked documentation to not imply that
> userspace "must" invoke the ioctl.  I think this is the last patch I'll throw
> into misc for 6.17?  So in theory, if it breaks userspace, I can simply
> truncate it from the pull request.

Thanks!

> 
> [1/2] KVM: x86: Reject KVM_SET_TSC_KHZ VM ioctl when vCPUs have been created
>       https://github.com/kvm-x86/linux/commit/dcbe5a466c12
> [2/2] KVM: x86: Reject KVM_SET_TSC_KHZ vCPU ioctl for TSC protected guest
>       https://github.com/kvm-x86/linux/commit/e51cf184d90c

Btw, in the second patch it seems you have:

  Fixes; adafea1 ("KVM: x86: Add infrastructure for secure TSC")

Shouldn't we follow the standard format, i.e.,

  Fixes: adafea110600 ("KVM: x86: Add infrastructure for secure TSC")


?