From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-comment-return-653-cohuck=redhat.com@lists.oasis-open.org Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Date: Mon, 25 Feb 2019 18:45:06 +0000 From: "Dr. David Alan Gilbert" Message-ID: <20190225184506.GF2710@work-vm> References: <20190222115433.7160-1-dgilbert@redhat.com> <20190222115433.7160-4-dgilbert@redhat.com> <20190225165014.GE379@stefanha-x1.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190225165014.GE379@stefanha-x1.localdomain> Subject: Re: [virtio-comment] Re: [PATCH v2 3/3] shared memory: Define mmio registers To: Stefan Hajnoczi Cc: virtio-comment@lists.oasis-open.org, virtio-dev@lists.oasis-open.org, cohuck@redhat.com List-ID: * Stefan Hajnoczi (stefanha@redhat.com) wrote: > On Fri, Feb 22, 2019 at 11:54:33AM +0000, Dr. David Alan Gilbert (git) wrote: > > diff --git a/content.tex b/content.tex > > index 9838208..c3070bd 100644 > > --- a/content.tex > > +++ b/content.tex > > @@ -1726,6 +1726,28 @@ All register values are organized as Little Endian. > > selected by writing to \field{QueueSel}. > > } > > \hline > > + \mmioreg{SHMId}{Shared memory id}{0x0ac}{W}{% > > + Writing to this register selects the shared memory region \ref{sec:Basic Facilities of a Virtio Device / Shared Memory Regions} > > + following operations on \field{SHMLenLow}, \field{SHMLenHigh}, > > + \field{SHMBaseLow} and \field{SHMBaseHigh} apply to. > > + } > > + \hline > > + \mmiodreg{SHMLenLow}{SHMLenHigh}{Shared memory region 64 bit long length}{0x0b0}{0x0xb4}{R}{% > > QueueDescLow/High explicitly documents the low and high 32 bits > relationship of these two registers. Please do the same of > SHMLenLow/High and SHMBaseLow/High for clarity and consistency. That > way readers know the purpose of Low and High. Done (and to SHMBase) > > > + These registers return the length of the shared memory > > Adding "in bytes" makes the units explicit. Done > > + region, as defined by the device for the region selected by > > + the \field{SHMId} register. Reading from a non-existent > > + region (i.e. where the ID written to \field{SHMId} is unused) > > + results in a length of -1. > > -1 is used to indicate the absence of a region, does 0 have a meaning? No, I'd be happy to switch; although this does lead to another question; what happens on an older virtio-mmio implementation when a device tries to read these registers to detect if the region exists? > > @@ -1761,6 +1783,9 @@ driver seeing an inconsistent configuration state. > > > > The device MUST NOT access virtual queue contents when \field{QueueReady} is zero (0x0). > > > > +The device MUST NOT respond to SHM Base writes for none-existent > > s/none/non/ Done -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK This publicly archived list offers a means to provide input to the OASIS Virtual I/O Device (VIRTIO) TC. In order to verify user consent to the Feedback License terms and to minimize spam in the list archive, subscription is required before posting. Subscribe: virtio-comment-subscribe@lists.oasis-open.org Unsubscribe: virtio-comment-unsubscribe@lists.oasis-open.org List help: virtio-comment-help@lists.oasis-open.org List archive: https://lists.oasis-open.org/archives/virtio-comment/ Feedback License: https://www.oasis-open.org/who/ipr/feedback_license.pdf List Guidelines: https://www.oasis-open.org/policies-guidelines/mailing-lists Committee: https://www.oasis-open.org/committees/virtio/ Join OASIS: https://www.oasis-open.org/join/