From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-dev-return-6674-cohuck=redhat.com@lists.oasis-open.org Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 4867E985F0A for ; Tue, 21 Jan 2020 06:19:55 +0000 (UTC) From: Jing Liu Date: Tue, 21 Jan 2020 21:54:33 +0800 Message-Id: <1579614873-21907-6-git-send-email-jing2.liu@linux.intel.com> In-Reply-To: <1579614873-21907-1-git-send-email-jing2.liu@linux.intel.com> References: <1579614873-21907-1-git-send-email-jing2.liu@linux.intel.com> Subject: [virtio-dev] [PATCH v2 5/5] virtio-mmio: MSI vector and event mapping Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable To: virtio-dev@lists.oasis-open.org Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, qemu-devel@nongnu.org, Jing Liu , Chao Peng , Liu Jiang , Zha Bin List-ID: Bit 1 msi_sharing reported in the MsiState register indicates the mapping m= ode device uses. Bit 1 is 0 - device uses MSI non-sharing mode. This indicates vector per ev= ent and fixed static vectors and events relationship. This fits for devices with a = high interrupt rate and best performance; Bit 1 is 1 - device uses MSI sharing mode. This indicates vectors and event= s dynamic mapping and fits for devices not requiring a high interrupt rate. Co-developed-by: Chao Peng Signed-off-by: Chao Peng Co-developed-by: Liu Jiang Signed-off-by: Liu Jiang Co-developed-by: Zha Bin Signed-off-by: Zha Bin Signed-off-by: Jing Liu --- content.tex | 48 +++++++++++++++++++++++++++++++++++++++++++++++- msi-state.c | 3 ++- 2 files changed, 49 insertions(+), 2 deletions(-) diff --git a/content.tex b/content.tex index dcf6c71..2fd1686 100644 --- a/content.tex +++ b/content.tex @@ -1770,7 +1770,8 @@ \subsection{MMIO Device Register Layout}\label{sec:Vi= rtio Transport Options / Vi \hline \mmioreg{MsiState}{MSI state}{0x0c4}{R}{% When VIRTIO_F_MMIO_MSI has been negotiated, reading - from this register returns the global MSI enable/disable status. + from this register returns the global MSI enable/disable status + and whether device uses MSI sharing mode. \lstinputlisting{msi-state.c} } \hline @@ -1926,12 +1927,18 @@ \subsubsection{Device Initialization}\label{sec:Vir= tio Transport Options / Virti mask and unmask the MSI vector applying to the one selected by writing to \field{MsiVecSel}. =20 +VIRTIO_MMIO_MSI_CMD_MAP_CONFIG command is to set the configuration event a= nd MSI vector +mapping. VIRTIO_MMIO_MSI_CMD_MAP_QUEUE is to set the queue event and MSI v= ector +mapping. They SHOULD only be used in MSI sharing mode. + \begin{lstlisting} #define VIRTIO_MMIO_MSI_CMD_ENABLE 0x1 #define VIRTIO_MMIO_MSI_CMD_DISABLE 0x2 #define VIRTIO_MMIO_MSI_CMD_CONFIGURE 0x3 #define VIRTIO_MMIO_MSI_CMD_MASK 0x4 #define VIRTIO_MMIO_MSI_CMD_UNMASK 0x5 +#define VIRTIO_MMIO_MSI_CMD_MAP_CONFIG 0x6 +#define VIRTIO_MMIO_MSI_CMD_MAP_QUEUE 0x7 \end{lstlisting} =20 Setting a special NO_VECTOR value means disabling an interrupt for an even= t type. @@ -1941,10 +1948,49 @@ \subsubsection{Device Initialization}\label{sec:Vir= tio Transport Options / Virti #define VIRTIO_MMIO_MSI_NO_VECTOR 0xffffffff \end{lstlisting} =20 +\subparagraph{MSI Vector and Event Mapping}\label{sec:Virtio Transport Opt= ions / Virtio Over MMIO / MMIO-specific Initialization And Device Operation= / Device Initialization / MSI Vector Configuration} +The reported \field{msi_sharing} bit in the \field{MsiState} return value = shows +the MSI sharing mode that device uses. + +When \field{msi_sharing} bit is 0, it indicates the device uses non-sharin= g mode +and vector per event fixed static relationship is used. The first vector i= s for device +configuraiton change event, the second vector is for virtqueue 1, the thir= d vector +is for virtqueue 2 and so on. + +When \field{msi_sharing} bit is 1, it indicates the device uses MSI sharin= g mode, +and the vector and event mapping is dynamic. Writing \field{MsiVecSel} +followed by writing VIRTIO_MMIO_MSI_CMD_MAP_CONFIG/VIRTIO_MMIO_MSI_CMD_MAP= _QUEUE command +maps interrupts triggered by the configuration change/selected queue event= s respectively +to the corresponding MSI vector. + +\devicenormative{\subparagraph}{MSI Vector Configuration}{Virtio Transport= Options / Virtio Over MMIO / MMIO-specific Initialization And Device Opera= tion / MSI Vector Configuration} + +When the device reports \field{msi_sharing} bit as 0, it SHOULD support a = number of +vectors that greater than the maximum number of virtqueues. +Device MUST report the number of vectors supported in \field{MsiVecNum}. + +When the device reports \field{msi_sharing} bit as 1, it SHOULD support at= least +2 MSI vectors and MUST report in \field{MsiVecNum}. Device SHOULD support = mapping any +event type to any vector under \field{MsiVecNum}. + +Device MUST support unmapping any event type (NO_VECTOR). + +The device SHOULD restrict the reported \field{msi_sharing} and \field{Msi= VecNum} +to a value that might benefit system performance. + +\begin{note} +For example, a device which does not expect to send interrupts at a high r= ate might +return \field{msi_sharing} bit as 1. +\end{note} + \drivernormative{\subparagraph}{MSI Vector Configuration}{Virtio Transport= Options / Virtio Over MMIO / MMIO-specific Initialization And Device Opera= tion / MSI Vector Configuration} When VIRTIO_F_MMIO_MSI has been negotiated, driver should try to configure and enable MSI. =20 +To set up the event and vector mapping for MSI sharing mode, driver SHOULD +write a valid \field{MsiVecSel} followed by VIRTIO_MMIO_MSI_CMD_MAP_CONFIG= /VIRTIO_MMIO_MSI_CMD_MAP_QUEUE +command to map the configuration change/selected queue events respectively= . + To configure MSI vector, driver SHOULD firstly specify the MSI vector inde= x by writing to \field{MsiVecSel}. Then notify the MSI address and data by writing to \field{MsiAddrLow}, \fi= eld{MsiAddrHigh}, diff --git a/msi-state.c b/msi-state.c index b1fa0c1..d470be4 100644 --- a/msi-state.c +++ b/msi-state.c @@ -1,4 +1,5 @@ le32 { msi_enabled : 1; - reserved : 31; + msi_sharing: 1; + reserved : 30; }; --=20 2.7.4 --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org