linux-kernel - Re: [PATCH v2 0/8] KVM: SVM: Fix exit

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Message-ID: <176849898589.719783.8437609817202022715.b4-ty@google.com>
Date: Thu, 15 Jan 2026 10:03:34 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>, 
	Vitaly Kuznetsov <vkuznets@...hat.com>, "K. Y. Srinivasan" <kys@...rosoft.com>, 
	Haiyang Zhang <haiyangz@...rosoft.com>, Wei Liu <wei.liu@...nel.org>, 
	Dexuan Cui <decui@...rosoft.com>, Long Li <longli@...rosoft.com>
Cc: kvm@...r.kernel.org, linux-hyperv@...r.kernel.org, 
	linux-kernel@...r.kernel.org, Jim Mattson <jmattson@...gle.com>, 
	Yosry Ahmed <yosry.ahmed@...ux.dev>
Subject: Re: [PATCH v2 0/8] KVM: SVM: Fix exit_code bugs

On Tue, 30 Dec 2025 13:13:39 -0800, Sean Christopherson wrote:
> Fix (mostly benign) bugs in SVM where KVM treats exit codes as 32-bit values
> instead of 64-bit values.
> 
> The most dangerous aspect of the mess is that simply fixing KVM would likely
> break KVM-on-KVM setups if only L1 is patched.  To try and avoid such
> breakage while also fixing KVM, I opted to have KVM retain its checks on
> only bits 31:0 if KVM is running as a VM (as detected by
> X86_FEATURE_HYPERVISOR).
> 
> [...]

Applied to kvm-x86 svm, thanks!

[1/8] KVM: SVM: Add a helper to detect VMRUN failures
      https://github.com/kvm-x86/linux/commit/217463aa329e
[2/8] KVM: SVM: Open code handling of unexpected exits in svm_invoke_exit_handler()
      https://github.com/kvm-x86/linux/commit/2450c9774510
[3/8] KVM: SVM: Check for an unexpected VM-Exit after RETPOLINE "fast" handling
      https://github.com/kvm-x86/linux/commit/194c17bf5eba
[4/8] KVM: SVM: Filter out 64-bit exit codes when invoking exit handlers on bare metal
      https://github.com/kvm-x86/linux/commit/405fce694bd1
[5/8] KVM: SVM: Treat exit_code as an unsigned 64-bit value through all of KVM
      https://github.com/kvm-x86/linux/commit/d7507a94a072
[6/8] KVM: SVM: Limit incorrect check on SVM_EXIT_ERR to running as a VM
      https://github.com/kvm-x86/linux/commit/a08ca6691fd3
[7/8] KVM: SVM: Harden exit_code against being used in Spectre-like attacks
      https://github.com/kvm-x86/linux/commit/1e3dddafecee
[8/8] KVM: SVM: Assert that Hyper-V's HV_SVM_EXITCODE_ENL == SVM_EXIT_SW
      https://github.com/kvm-x86/linux/commit/d6c20d19f7d3

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