linux-kernel - Re: [PATCH v2 00/11] KVM: x86: Fix emulation of (some) L2 instructions

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Message-ID: <174041647496.2342481.7530493639328581793.b4-ty@google.com>
Date: Fri, 28 Feb 2025 09:06:26 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 00/11] KVM: x86: Fix emulation of (some) L2 instructions

On Fri, 31 Jan 2025 17:55:07 -0800, Sean Christopherson wrote:
> Fix a variety of bugs related to emulating instructions on behalf of L2,
> and (finally) add support for synthesizing nested VM-Exit to L1 when L1
> wants to intercept an instruction (KVM currently injects a #UD into L2).
> 
> There's no real motivation behind this series.  I spotted the PAUSE_EXITING
> vs. BUS_LOCK_DETECTION goof when sorting out a report/question about HLT
> emulation in L2 doing weird things, and then stupidly thought "how hard can
> it be to generate a VM-Exit?".  Turns out, not that hard, but definitely
> a bit harder than I was anticipating due to the annoying RIP vs. next RIP
> flaw.
> 
> [...]

Applied to kvm-x86 misc, thanks!

[01/11] KVM: nVMX: Check PAUSE_EXITING, not BUS_LOCK_DETECTION, on PAUSE emulation
        https://github.com/kvm-x86/linux/commit/f002a97ec8c9
[02/11] KVM: nSVM: Pass next RIP, not current RIP, for nested VM-Exit on emulation
        https://github.com/kvm-x86/linux/commit/c8e612bfedff
[03/11] KVM: nVMX: Allow emulating RDPID on behalf of L2
        https://github.com/kvm-x86/linux/commit/3244616aac8d
[04/11] KVM: nVMX: Emulate HLT in L2 if it's not intercepted
        https://github.com/kvm-x86/linux/commit/f43f7a215af0
[05/11] KVM: nVMX: Consolidate missing X86EMUL_INTERCEPTED logic in L2 emulation
        https://github.com/kvm-x86/linux/commit/08e3d89eb330
[06/11] KVM: x86: Plumb the src/dst operand types through to .check_intercept()
        https://github.com/kvm-x86/linux/commit/407d03fe924c
[07/11] KVM: x86: Plumb the emulator's starting RIP into nested intercept checks
        https://github.com/kvm-x86/linux/commit/9aeb9d8a6738
[08/11] KVM: x86: Add a #define for the architectural max instruction length
        https://github.com/kvm-x86/linux/commit/d4aea23fd0ff
[09/11] KVM: nVMX: Allow the caller to provide instruction length on nested VM-Exit
        https://github.com/kvm-x86/linux/commit/fbd1e0f19546
[10/11] KVM: nVMX: Synthesize nested VM-Exit for supported emulation intercepts
        https://github.com/kvm-x86/linux/commit/79a14afc6090
[11/11] KVM: selftests: Add a nested (forced) emulation intercept test for x86
        https://github.com/kvm-x86/linux/commit/2428865bf0af

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