On Fri, Nov 12, 2021 at 11:35 AM Cornelia Huck <coh...@redhat.com> wrote: > > On Thu, Nov 11 2021, Eugenio Pérez <epere...@redhat.com> wrote: > > > 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 > > I think MMIO uses that mechanism as well? > > > 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 <epere...@redhat.com> > > --- > > 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. > > I think we need to distinguish "driver wants to clear a status bit" from > "driver is initiating a reset, and that transport implements that by > writing 0 to the device status". So, what about > > "The driver MUST NOT clear a \field{device status} bit, except when > setting \field{device status} to 0 as a transport-specific way to > intitiate a reset." > > If we introduce driver-clearable bits later, we can simply make that > "The driver MUST NOT clear a \field{device status} bit other than > NEW_BIT, ..." >
The intention is to introduce a driver-clearable bit in the next patch, but I should have stated better in the patch message. Definitely I should have stated it better in the message. Thanks! --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscr...@lists.oasis-open.org For additional commands, e-mail: virtio-dev-h...@lists.oasis-open.org