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Fri, 17 Jul 2020 16:23:19 +0000 (UTC) Date: Fri, 17 Jul 2020 10:23:19 -0600 From: Alex Williamson To: Peter Maydell Subject: Re: [PATCH v3 3/9] vfio: add quirk device write method Message-ID: <20200717102319.77d5b529@x1.home> In-Reply-To: References: <20200630122710.1119158-1-ppandit@redhat.com> <20200630122710.1119158-4-ppandit@redhat.com> <20200717095352.45845d8a@x1.home> Organization: Red Hat MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=207.211.31.81; envelope-from=alex.williamson@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/17 05:27:47 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Prasad J Pandit , Alex =?UTF-8?B?QmVubsOpZQ==?= , Li Qiang , QEMU Developers , P J P , Lei Sun , Paolo Bonzini , Philippe =?UTF-8?B?TWF0aGlldS1EYXVkw6k=?= , David Gibson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, 17 Jul 2020 16:57:40 +0100 Peter Maydell wrote: > On Fri, 17 Jul 2020 at 16:54, Alex Williamson > wrote: > > > > On Thu, 16 Jul 2020 18:46:33 +0100 > > Peter Maydell wrote: > > > > > Alex (Williamson) -- as the vfio maintainer, do you have a view > > > on whether we should be logging write accesses to port 0x3c3 > > > here as guest-errors or unimplemented-QEMU-functionality? > > > > > > Guest-error seems plausible to me, anyway. > > > > I believe the intention was that writes would be dropped, so if this > > generates logging that is going to cause users to file bugs, that would > > be undesirable. Thanks, > > It will only log if the user explicitly turns on "log things the > guest does which are bugs in it, like writing to read-only > registers" (with the '-d guest_errors' option). IIRC, this quirk is based on observation more so than an actual spec, so whether a log of such an event is interpreted as a guest error or an emulation error might be up for debate. Aside from that nit, and lack of bandwidth to research how hardware handles writes, Acked-by: Alex Williamson Thanks, Alex