From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: Date: Wed, 15 Feb 2023 02:53:34 +0200 Subject: Re: [virtio-comment] [PATCH v10 05/10] pci: add admin vq registers to virtio over pci References: <20230209121221.15118-1-mst@redhat.com> <20230209121221.15118-6-mst@redhat.com> From: Max Gurtovoy In-Reply-To: MIME-Version: 1.0 Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit To: David Edmondson , "Michael S. Tsirkin" Cc: virtio-dev@lists.oasis-open.org, jasowang@redhat.com, cohuck@redhat.com, sgarzare@redhat.com, stefanha@redhat.com, nrupal.jani@intel.com, Piotr.Uminski@intel.com, hang.yuan@intel.com, virtio@lists.oasis-open.org, Zhu Lingshan , pasic@linux.ibm.com, Shahaf Shuler , Parav Pandit , virtio-comment@lists.oasis-open.org List-ID: On 13/02/2023 14:21, David Edmondson wrote: > > On Thursday, 2023-02-09 at 07:13:48 -05, Michael S. Tsirkin wrote: >> @@ -1031,6 +1035,19 @@ \subsubsection{Common configuration structure layout}\label{sec:Virtio Transport >> This field exists only if VIRTIO_F_RING_RESET has been >> negotiated. (see \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}). >> >> +\item[\field{admin_queue_index}] >> + The device uses this to report the index of the first administration virtqueue. >> + This field is valid only if VIRTIO_F_ADMIN_VQ has been negotiated. >> +\item[\field{admin_queue_num}] >> + The device uses this to report the number of the >> + supported administration virtqueues. Virtqueues with index >> + between \field{admin_queue_index} and (\field{admin_queue_index} + >> + \field{admin_queue_num}) inclusive serve as administration >> + virtqueues. >> + Thus the number of administration virtqueues equals >> + (\field{admin_queue_num} + 1). > > Really the number of queues is "admin_queue_num + 1"? > > That seems ... odd. It's not odd if we'll mention that this is a zero based value. MST, can you add it please for the next version ? > >> + This field is valid only if VIRTIO_F_ADMIN_VQ has been >> + negotiated. >> \end{description} >> >> \devicenormative{\paragraph}{Common configuration structure layout}{Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Common configuration structure layout} >> @@ -1117,6 +1134,14 @@ \subsubsection{Common configuration structure layout}\label{sec:Virtio Transport >> were used before the queue reset. >> (see \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}). >> >> +If VIRTIO_F_ADMIN_VQ has been negotiated, and if the driver >> +configures any administration virtqueues, the driver MUST >> +configure the administration virtqueues using the index >> +in the range \field{admin_queue_index} to >> +\field{admin_queue_index} + \field{admin_queue_num} inclusive. >> +The driver MAY configure less administration virtqueues than >> +supported by the device. >> + >> \subsubsection{Notification structure layout}\label{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Notification capability} >> >> The notification location is found using the VIRTIO_PCI_CAP_NOTIFY_CFG >> @@ -7684,6 +7709,15 @@ \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits} >> >> \item[VIRTIO_F_ADMIN_VQ(41)] This feature indicates that the device exposes one or more >> administration virtqueues. >> + At the moment this feature is only supported for devices using >> + \ref{sec:Virtio Transport Options / Virtio Over PCI >> + Bus}~\nameref{sec:Virtio Transport Options / Virtio Over PCI Bus} >> + as the transport and is reserved for future use for >> + devices using other transports (see >> + \ref{drivernormative:Basic Facilities of a Virtio Device / Feature Bits} >> + and >> + \ref{devicenormative:Basic Facilities of a Virtio Device / Feature Bits} for >> + handling features reserved for future use. >> >> \end{description}