Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH] KVM/VMX: Invoke NMI non-IST entry instead of IST entry
To:     Andy Lutomirski <luto@amacapital.net>,
        Sean Christopherson <seanjc@google.com>
Cc:     Maxim Levitsky <mlevitsk@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Lai Jiangshan <jiangshanlai@gmail.com>,
        linux-kernel@vger.kernel.org,
        Lai Jiangshan <laijs@linux.alibaba.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Andi Kleen <ak@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Uros Bizjak <ubizjak@gmail.com>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Alexandre Chartre <alexandre.chartre@oracle.com>,
        Juergen Gross <JGross@suse.com>,
        Joerg Roedel <jroedel@suse.de>, Jian Cai <caij2003@gmail.com>
References: <YJG6ztbGjtuctec4@google.com>
 <38B9D60F-F24F-4910-B2DF-2A57F1060452@amacapital.net>
From:   Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <625057c7-ea40-4f37-8bea-cddecfe1b855@redhat.com>
Date:   Tue, 4 May 2021 23:25:23 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.8.1
MIME-Version: 1.0
In-Reply-To: <38B9D60F-F24F-4910-B2DF-2A57F1060452@amacapital.net>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 04/05/21 23:23, Andy Lutomirski wrote:
>> On May 4, 2021, at 2:21 PM, Sean Christopherson <seanjc@google.com> wrote:
>> FWIW, NMIs are masked if the VM-Exit was due to an NMI.

Huh, indeed:  "An NMI causes subsequent NMIs to be blocked, but only 
after the VM exit completes".

> Then this whole change is busted, since nothing will unmask NMIs. Revert it?

Looks like the easiest way out indeed.

Paolo