[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]
Subject: Re: [PATCH] virtio: introduce SUSPEND bit in device status
On 2/18/2024 10:11 PM, Michael S. Tsirkin wrote:
On Sun, Feb 18, 2024 at 09:23:06PM +0800, Zhu Lingshan wrote:This commit allows the driver to suspend the device by introducing a new status bit SUSPEND in device_status. This commit also introduce a new feature bit VIRTIO_F_SUSPEND which indicating whether the device support SUSPEND. This SUSPEND bit is transport-independent. Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com> Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Eugenio PÃrez <eperezma@redhat.com>Could we get some kind of dscription how this has taken into consideration the proposal from David Stevens?
sure thing, we can work with David together for a solution.
I find it really tiring when there are competing patches with authors ignoring each other's work and leaving it up to reviewers to figure out how do the patches compare.--- content.tex | 34 ++++++++++++++++++++++++++++++++-- 1 file changed, 32 insertions(+), 2 deletions(-) diff --git a/content.tex b/content.tex index 0a62dce..3d656b5 100644 --- a/content.tex +++ b/content.tex @@ -49,6 +49,9 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev\item[DEVICE_NEEDS_RESET (64)] Indicates that the device has experiencedan error from which it can't recover. + +\item[SUSPEND (16)] When VIRTIO_F_SUSPEND is negotiated, indicates that the + device has been suspended by the driver. \end{description}The \field{device status} field starts out as 0, and is reinitialized to 0 by@@ -73,6 +76,10 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev recover by issuing a reset. \end{note}+The driver SHOULD NOT set SUSPEND if FEATURES_OK is not set.+ +When setting SUSPEND, the driver MUST re-read \field{device status} to ensure the SUSPEND bit is set. + \devicenormative{\subsection}{Device Status Field}{Basic Facilities of a Virtio Device / Device Status Field}The device MUST NOT consume buffers or send any used buffer@@ -82,6 +89,25 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev that a reset is needed. If DRIVER_OK is set, after it sets DEVICE_NEEDS_RESET, the device MUST send a device configuration change notification to the driver.+The device MUST ignore SUSPEND if FEATURES_OK is not set.+ +The device MUST ignore SUSPEND if VIRTIO_F_SUSPEND is not negotiated. + +The device SHOULD allow settings to \field{device status} even when SUSPEND is set. + +If VIRTIO_F_SUSPEND is negotiated and SUSPEND is set, the device SHOULD clear SUSPEND +and resumes operation upon DRIVER_OK. + +If VIRTIO_F_SUSPEND is negotiated, when the driver sets SUSPEND, +the device SHOULD perform the following actions before presenting SUSPEND bit in the \field{device status}: + +\begin{itemize} +\item Stop consuming buffers of any virtqueues and mark all finished descriptors as used. +\item Wait until all descriptors that being processed to finish and mark them as used. +\item Flush all used buffer and send used buffer notifications to the driver. +\item Pause its operation except \field{device status} and preserve configurations in its Device Configuration Space, see \ref{sec:Basic Facilities of a Virtio Device / Device Configuration Space} +\end{itemize} + \section{Feature Bits}\label{sec:Basic Facilities of a Virtio Device / Feature Bits}Each virtio device offers all the features it understands. During@@ -99,10 +125,10 @@ \section{Feature Bits}\label{sec:Basic Facilities of a Virtio Device / Feature B \begin{description} \item[0 to 23, and 50 to 127] Feature bits for the specific device type-\item[24 to 41] Feature bits reserved for extensions to the queue and+\item[24 to 42] Feature bits reserved for extensions to the queue and feature negotiation mechanisms-\item[42 to 49, and 128 and above] Feature bits reserved for future extensions.+\item[43 to 49, and 128 and above] Feature bits reserved for future extensions. \end{description}\begin{note}@@ -872,6 +898,10 @@ \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits} \ref{devicenormative:Basic Facilities of a Virtio Device / Feature Bits} for handling features reserved for future use.+ \item[VIRTIO_F_SUSPEND(42)] This feature indicates that the driver can+ SUSPEND the device. + See \ref{sec:Basic Facilities of a Virtio Device / Device Status Field}. + \end{description}\drivernormative{\section}{Reserved Feature Bits}{Reserved Feature Bits}-- 2.35.3
[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]