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[80.230.25.45]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49092968066sm15584235e9.15.2026.05.27.22.22.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 27 May 2026 22:22:17 -0700 (PDT) Date: Thu, 28 May 2026 01:22:15 -0400 From: "Michael S. Tsirkin" To: Demi Marie Obenour Cc: "virtio-comment@lists.linux.dev" Subject: Re: MSI-X vector limits and reserving a virtio device ID Message-ID: <20260528010721-mutt-send-email-mst@kernel.org> References: <11771164-7919-43e1-a980-03f036bdae2e@gmail.com> Precedence: bulk X-Mailing-List: virtio-comment@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <11771164-7919-43e1-a980-03f036bdae2e@gmail.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: rA_WEXC4MYp0ZgfH1B-wY4-IU8R80Vn45FbhXdidTiM_1779945739 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Wed, May 27, 2026 at 07:53:11PM -0400, Demi Marie Obenour wrote: > I'd like to reserve a virtio device ID for virtio vhost-guest, > formally virtio vhost-user. Would this be possible? yes, follow the regular process for reserving IDs. > Also, I'd like to know which systems have a small limit on the number > of MSI-X vectors. The vhost-guest device uses lots of MSI-X vectors. > Typical implementations will use 256 * 3 + 7 = 775 of them! That can, > of course, be reduced by sharing vectors, but this is undesirable > as it comes at a performance cost. A single cpu x86 system? > -- > Sincerely, > Demi Marie Obenour (she/her/hers)