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Tsirkin" To: David Woodhouse Cc: qemu-devel@nongnu.org, Marcel Apfelbaum , Paolo Bonzini , Richard Henderson , Eduardo Habkost , Marcelo Tosatti , Alex Williamson , paul@xen.org Subject: Re: [RFC] Notify IRQ sources of level interrupt ack/EOI Message-ID: <20230111112425-mutt-send-email-mst@kernel.org> References: <23caafffdd9546b8eeff851660015f3bfc021ed3.camel@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <23caafffdd9546b8eeff851660015f3bfc021ed3.camel@infradead.org> Received-SPF: pass client-ip=170.10.133.124; envelope-from=mst@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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_H2=-0.001, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, Jan 11, 2023 at 02:41:58PM +0000, David Woodhouse wrote: > This allows drivers to register a callback on a qemu_irq, which is > invoked when a level-triggered IRQ is acked on the irqchip. > > This allows us to simulate level-triggered interrupts more efficiently, > by resampling the state of the interrupt only when it actually matters. I think we tried this with vfio and had to give up on this. I don't remember the details though. Alex probably does?