From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= Subject: [PATCH v3 1/2] content: Explain better the status clearing bits Date: Thu, 11 Nov 2021 19:58:11 +0100 Message-Id: <20211111185812.2326093-2-eperezma@redhat.com> In-Reply-To: <20211111185812.2326093-1-eperezma@redhat.com> References: <20211111185812.2326093-1-eperezma@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: virtio-dev@lists.oasis-open.org, virtio-comment@lists.oasis-open.org, mst@redhat.com, jasowang@redhat.com Cc: amikheev@nvidia.com, stefanha@redhat.com, shahafs@nvidia.com, oren@nvidia.com, pasic@linux.ibm.com, cohuck@redhat.com, bodong@nvidia.com, "Dr . David Alan Gilbert" , parav@nvidia.com, mgurtovoy@nvidia.com List-ID: The spec tells that "The driver MUST NOT clear a device status bit", but a device using PCI transport reset a virtio device writing 0 to device status. In some way, that is to clear all its bits. Instead of add an exception, tell explicitely the status bits that the driver cannot clear anytime in a normal operation, so conformant device and drivers keeps being conformant. Signed-off-by: Eugenio Pérez --- content.tex | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/content.tex b/content.tex index 5d112af..2aa3006 100644 --- a/content.tex +++ b/content.tex @@ -60,9 +60,10 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev initialization sequence specified in \ref{sec:General Initialization And Device Operation / Device Initialization}. -The driver MUST NOT clear a -\field{device status} bit. If the driver sets the FAILED bit, -the driver MUST later reset the device before attempting to re-initialize. +The driver MUST NOT clear ACKNOWLEDGE, DRIVER, DRIVER_OK, FEATURES_OK or +DEVICE_NEEDS_RESET bits of \field{device status}, except if resetting the whole +device. If the driver sets the FAILED bit, the driver MUST later reset the +device before attempting to re-initialize. The driver SHOULD NOT rely on completion of operations of a device if DEVICE_NEEDS_RESET is set. -- 2.27.0