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Peter Anvin" , Thomas Gleixner , Joerg Roedel , Suravee Suthikulpanit , Robin Murphy , iommu@lists.linux.dev, Paolo Bonzini Date: Tue, 10 Sep 2024 16:13:07 -0400 In-Reply-To: <1d6044e0d71cd95c477e319d7e47819eee61a8fc.camel@redhat.com> References: <20231002115723.175344-1-mlevitsk@redhat.com> <1d6044e0d71cd95c477e319d7e47819eee61a8fc.camel@redhat.com> User-Agent: Evolution 3.36.5 (3.36.5-2.fc32) Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit On Wed, 2023-10-04 at 16:14 +0300, Maxim Levitsky wrote: > У пн, 2023-10-02 у 12:21 -0700, Sean Christopherson пише: > > On Mon, Oct 02, 2023, Maxim Levitsky wrote: > > > Hi! > > > > > > This patch allows AVIC's ICR emulation to be optional and thus allows > > > to workaround AVIC's errata #1235 by disabling this portion of the feature. > > > > > > This is v3 of my patch series 'AVIC bugfixes and workarounds' including > > > review feedback. > > > > Please respond to my idea[*] instead of sending more patches. > > Hi, > > For the v2 of the patch I was already on the fence if to do it this way or to refactor > the code, and back when I posted it, I decided still to avoid the refactoring. > > However, your idea of rewriting this patch, while it does change less lines of code, > is even less obvious and consequently required you to write even longer comment to > justify it which is not a good sign. > > In particular I don't want someone to find out later, and in the hard way that sometimes > real physid table is accessed, and sometimes a fake copy of it is. > > So I decided to fix the root cause by not reading the physid table back, > which made the code cleaner, and even with the workaround the code > IMHO is still simpler than it was before. > > About the added 'vcpu->loaded' variable, I added it also because it is something that is > long overdue to be added, I remember that in IPIv code there was also a need for this, > and probalby more places in KVM can be refactored to take advantage of it, > instead of various hacks. > > I did adopt your idea of using 'enable_ipiv', although I am still not 100% sure that this > is more readable than 'avic_zen2_workaround'. Hi! Sean, can you take another look at this patch series? Thanks in advance, Maxim Levitsky > > Best regards, > Maxim Levitsky > > > I'm not opposed to > > a different approach, but we need to have an actual discussion around the pros and > > cons, and hopefully come to an agreement. This cover letter doesn't even acknowledge > > that there is an alternative proposal, let alone justify why the vcpu->loaded > > approach was taken. > > > > [*] https://lore.kernel.org/all/ZRYxPNeq1rnp-M0f@google.com > > > >