Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 6 Jun 2023 10:22:14 -0700
In-Reply-To: <87wn0hnxh7.fsf@nvidia.com>
Mime-Version: 1.0
References: <20230602011518.787006-1-seanjc@google.com> <20230602011518.787006-2-seanjc@google.com>
 <87wn0hnxh7.fsf@nvidia.com>
Message-ID: <ZH9rRnU8h+gDZZuB@google.com>
Subject: Re: [PATCH 1/3] KVM: VMX: Retry APIC-access page reload if
 invalidation is in-progress
From:   Sean Christopherson <seanjc@google.com>
To:     Alistair Popple <apopple@nvidia.com>
Cc:     Paolo Bonzini <pbonzini@redhat.com>, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, Jason Gunthorpe <jgg@nvidia.com>,
        Robin Murphy <robin.murphy@arm.com>
Content-Type: text/plain; charset="us-ascii"
Precedence: bulk

On Tue, Jun 06, 2023, Alistair Popple wrote:
> 
> Thanks for doing this. I'm not overly familiar with KVM implementation
> but am familiar with mmu notifiers so read through the KVM usage. Looks
> like KVM is sort of doing something similar to what mmu_interval_notifiers
> do and I wonder if some of that could be shared.

They're very, very similar.  At a glance, KVM likely could be moved over to the
common interval tree implementation, but it would require a substantial amount of
work in KVM, and various extensions to the mmu notifiers too.  I definitely wouldn't
be opposed to converging KVM if someone wants to put in the effort, but at the same
time I wouldn't recommend that anyone actually do the work as the ROI is likely
very low.