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Date: Tue, 11 Jun 2024 18:18:36 -0700
In-Reply-To: <20240508132502.184428-1-julian.stecklina@cyberus-technology.de>
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Subject: Re: [PATCH] KVM: x86: add KVM_RUN_X86_GUEST_MODE kvm_run flag
From: Sean Christopherson <seanjc@google.com>
To: Sean Christopherson <seanjc@google.com>, Paolo Bonzini <pbonzini@redhat.com>, 
	Jonathan Corbet <corbet@lwn.net>, 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>, Julian Stecklina <julian.stecklina@cyberus-technology.de>
Cc: Thomas Prescher <thomas.prescher@cyberus-technology.de>, kvm@vger.kernel.org, 
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="utf-8"

On Wed, 08 May 2024 15:25:01 +0200, Julian Stecklina wrote:
> When a vCPU is interrupted by a signal while running a nested guest,
> KVM will exit to userspace with L2 state. However, userspace has no
> way to know whether it sees L1 or L2 state (besides calling
> KVM_GET_STATS_FD, which does not have a stable ABI).
> 
> This causes multiple problems:
> 
> [...]

Applied to kvm-x86 misc.  Note, the capability got number 237, as 236 was
claimed by KVM_CAP_X86_APIC_BUS_CYCLES_NS.  The number might also change again,
e.g. if a different arch adds a capability and x86 loses the race.

Thanks!

[1/1] KVM: x86: add KVM_RUN_X86_GUEST_MODE kvm_run flag
      https://github.com/kvm-x86/linux/commit/85542adb65ec

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