On Mon, 27 Sep 2021 16:51:43 +0200, Cornelia Huck <coh...@redhat.com> wrote: > On Mon, Sep 27 2021, Xuan Zhuo <xuanz...@linux.alibaba.com> wrote: > > > PCI support virtqueue reset. > > > > virtio_pci_common_cfg add "queue_reset" to support virtqueue reset. > > The driver uses this to selectively reset the queue. > > > > Signed-off-by: Xuan Zhuo <xuanz...@linux.alibaba.com> > > --- > > content.tex | 21 +++++++++++++++++++++ > > 1 file changed, 21 insertions(+) > > > > diff --git a/content.tex b/content.tex > > index 603b1f1..35228dc 100644 > > --- a/content.tex > > +++ b/content.tex > > @@ -896,6 +896,7 @@ \subsubsection{Common configuration structure > > layout}\label{sec:Virtio Transport > > le64 queue_driver; /* read-write */ > > le64 queue_device; /* read-write */ > > le16 queue_notify_data; /* read-only for driver */ > > + le16 queue_reset; /* read-write */ > > }; > > \end{lstlisting} > > > > @@ -975,6 +976,12 @@ \subsubsection{Common configuration structure > > layout}\label{sec:Virtio Transport > > may benefit from providing another value, for example an internal > > virtqueue > > identifier, or an internal offset related to the virtqueue number. > > \end{note} > > + > > +\item[\field{queue_reset}] > > + The driver uses this to selectively reset the queue. > > + This field exists only if VIRTIO_F_RING_RESET has been > > + negotiated. (see \ref{sec:Virtqueues / Virtqueue Reset}). > > + > > \end{description} > > > > \devicenormative{\paragraph}{Common configuration structure layout}{Virtio > > Transport Options / Virtio Over PCI Bus / PCI Device Layout / Common > > configuration structure layout} > > @@ -1016,6 +1023,14 @@ \subsubsection{Common configuration structure > > layout}\label{sec:Virtio Transport > > > > The device MUST present a 0 in \field{queue_enable} on reset. > > > > +The device MUST present a 0 in \field{queue_reset} after the virtqueue is > > +enabled with \field{queue_enable}. The device MUST reset the queue when 1 > > is > > +written to \field{queue_reset}, and present a 1 in \field{queue_reset} > > until the > > +queue is enabled with \field{queue_enable}. (see \ref{sec:Virtqueues / > > Virtqueue Reset}). > > "present a 1 in \field{queue_reset} after the queue has been reset, > until the driver re-enables the queue via \field{queue_enable}" > > ? >
Thanks. This is better. > I suppose queue_reset is reset to 0 when the whole device is reset? Yes, I will explain this in the next version. > > > + > > +The device MUST present a 0 in \field{queue_enable} after the virtqueue is > > reset > > +with \field{queue_reset}. (see \ref{sec:Virtqueues / Virtqueue Reset}). > > "after the driver has reset the virtqueue via \field{queue_reset}" ? Thanks. This is better. > > This section should probably also refer to the feature bit at least once? OK. > > > + > > The device MUST present a 0 in \field{queue_size} if the virtqueue > > corresponding to the current \field{queue_select} is unavailable. > > > > @@ -1040,6 +1055,12 @@ \subsubsection{Common configuration structure > > layout}\label{sec:Virtio Transport > > > > The driver MUST NOT write a 0 to \field{queue_enable}. > > > > +If the VIRTIO_F_RING_RESET feature bit is negotiated, the driver can stop > > using > > +the queue by writing a 1 to \field{queue_reset} and MUST read the value > > back to > > +ensure synchronization. Then optionally re-enable the queue by writing a 1 > > to > > +\field{queue_enable} after configuring the other virtqueue fields. (see > > +\ref{sec:Virtqueues / Virtqueue Reset}). > > "If VIRTIO_F_RING_RESET has been negotiated, after the driver writes 1 to > \field{queue_reset} to reset the queue, it MUST verify that the queue > has been reset by reading back \field{queue_reset} and ensuring that it > is 1. The driver MAY re-enable the queue by writing a 1 to > \field{queue_enable} after ensuring that the other virtqueue fields have > been set up correctly." > > ? Thanks. This is better. > > > + > > \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 > > MMIO can probably use a similar mechanism. > > For CCW, maybe we can add a payload to the existing RESET command if the > feature has been negotiated; the queue can be re-enabled by the normal > READ_VQ_CONF/SET_VQ procedure. I have not yet thought that through. Regarding CCW, can I consider adding this part later? This time I want to complete PCI and MMIO support for queue reset first. Thanks. --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscr...@lists.oasis-open.org For additional commands, e-mail: virtio-dev-h...@lists.oasis-open.org