From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-comment-return-803-cohuck=redhat.com@lists.oasis-open.org Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: From: "Dr. David Alan Gilbert (git)" Date: Fri, 12 Jul 2019 13:20:02 +0100 Message-Id: <20190712122002.10793-6-dgilbert@redhat.com> In-Reply-To: <20190712122002.10793-1-dgilbert@redhat.com> References: <20190712122002.10793-1-dgilbert@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [virtio-comment] [PATCH v7 5/5] shared memory: Define mmio registers To: virtio-dev@lists.oasis-open.org, virtio-comment@lists.oasis-open.org, stefanha@redhat.com, cohuck@redhat.com Cc: vgoyal@redhat.com List-ID: From: "Dr. David Alan Gilbert" Define an MMIO interface to discover and map shared memory regions. Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Stefan Hajnoczi Reviewed-by: Cornelia Huck --- content.tex | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/content.tex b/content.tex index 1476b0e..ee0d7c9 100644 --- a/content.tex +++ b/content.tex @@ -1736,6 +1736,33 @@ \subsection{MMIO Device Register Layout}\label{sec:Virtio Transport Options / Vi selected by writing to \field{QueueSel}. } \hline + \mmioreg{SHMSel}{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}{% + These registers return the length of the shared memory + region in bytes, as defined by the device for the region selected by + the \field{SHMSel} register. The lower 32 bits of the length + are read from \field{SHMLenLow} and the higher 32 bits from + \field{SHMLenHigh}. Reading from a non-existent + region (i.e. where the ID written to \field{SHMSel} is unused) + results in a length of -1. + } + \hline + \mmiodreg{SHMBaseLow}{SHMBaseHigh}{Shared memory region 64 bit long physical address}{0x0b8}{0x0xbc}{R}{% + The driver reads these registers to discover the base address + of the region in physical address space. This address is + chosen by the device (or other part of the VMM). + The lower 32 bits of the address are read from \field{SHMBaseLow} + with the higher 32 bits from \field{SHMBaseHigh}. Reading + from a non-existent region (i.e. where the ID written to + \field{SHMSel} is unused) results in a base address of + 0xffffffffffffffff. + } + \hline \mmioreg{ConfigGeneration}{Configuration atomicity value}{0x0fc}{R}{ Reading from this register returns a value describing a version of the device-specific configuration space (see \field{Config}). The driver can then access the configuration space and, when finished, read \field{ConfigGeneration} again. @@ -1825,6 +1852,9 @@ \subsubsection{Device Initialization}\label{sec:Virtio Transport Options / Virti and if its value is zero (0x0) MUST abort initialization and MUST NOT access any other register. +Drivers not expecting shared memory MUST NOT use the shared +memory registers. + Further initialization MUST follow the procedure described in \ref{sec:General Initialization And Device Operation / Device Initialization}~\nameref{sec:General Initialization And Device Operation / Device Initialization}. -- 2.21.0 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/