linux-kernel - Re: [PATCH v5 0/4] KVM: x86: User-return MSR fix+cleanups

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Message-ID: <176278796784.917175.10578129282144167896.b4-ty@google.com>
Date: Mon, 10 Nov 2025 07:37:21 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>, 
	"Kirill A. Shutemov" <kas@...nel.org>
Cc: kvm@...r.kernel.org, x86@...nel.org, linux-coco@...ts.linux.dev, 
	linux-kernel@...r.kernel.org, Yan Zhao <yan.y.zhao@...el.com>, 
	Xiaoyao Li <xiaoyao.li@...el.com>, Rick Edgecombe <rick.p.edgecombe@...el.com>, 
	Hou Wenlong <houwenlong.hwl@...group.com>
Subject: Re: [PATCH v5 0/4] KVM: x86: User-return MSR fix+cleanups

On Thu, 30 Oct 2025 12:15:24 -0700, Sean Christopherson wrote:
> Fix a bug in TDX where KVM will incorrectly update the current user-return
> MSR values when the TDX-Module doesn't actually clobber the relevant MSRs,
> and then cleanup and harden the user-return MSR code, e.g. against forced
> reboots.
> 
> v5:
>  - Set TDX MSRs to their expected post-run value during
>    tdx_prepare_switch_to_guest() instead of trying to predict what value
>    is in hardware after the SEAMCALL. [Yan]
>  - Free user_return_msrs at kvm_x86_vendor_exit(), not kvm_x86_exit(). [Chao]
> 
> [...]

Applied to kvm-x86 misc, thanks!

[1/4] KVM: TDX: Explicitly set user-return MSRs that *may* be clobbered by the TDX-Module
      https://github.com/kvm-x86/linux/commit/c0711f8c610e
[2/4] KVM: x86: WARN if user-return MSR notifier is registered on exit
      https://github.com/kvm-x86/linux/commit/b371174d2fa6
[3/4] KVM: x86: Leave user-return notifier registered on reboot/shutdown
      https://github.com/kvm-x86/linux/commit/2baa33a8ddd6
[4/4] KVM: x86: Don't disable IRQs when unregistering user-return notifier
      https://github.com/kvm-x86/linux/commit/995d504100cf

--
https://github.com/kvm-x86/linux/tree/next