From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-dev-return-6580-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 B2256985C94 for ; Thu, 2 Jan 2020 09:13:32 +0000 (UTC) References: <85eeab19-1f53-6c45-95a2-44c1cfd39184@redhat.com> <28da67db-73ab-f772-fb00-5a471b746fc5@linux.intel.com> <683cac51-853d-c8c8-24c6-b01886978ca4@redhat.com> From: "Liu, Jing2" Message-ID: <42346d41-b758-967a-30b7-95aa0d383beb@linux.intel.com> Date: Thu, 2 Jan 2020 17:13:28 +0800 MIME-Version: 1.0 In-Reply-To: <683cac51-853d-c8c8-24c6-b01886978ca4@redhat.com> Content-Language: en-US Subject: Re: [virtio-dev] Re: [PATCH v1 2/2] virtio-mmio: add features for virtio-mmio specification version 3 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable To: Jason Wang , Zha Bin , linux-kernel@vger.kernel.org Cc: mst@redhat.com, slp@redhat.com, virtio-dev@lists.oasis-open.org, gerry@linux.alibaba.com, jing2.liu@intel.com, chao.p.peng@intel.com List-ID: [...] >>> >>>> + >>>> +/* RO: MSI feature enabled mask */ >>>> +#define VIRTIO_MMIO_MSI_ENABLE_MASK=C2=A0=C2=A0=C2=A0 0x8000 >>>> +/* RO: Maximum queue size available */ >>>> +#define VIRTIO_MMIO_MSI_STATUS_QMASK=C2=A0=C2=A0=C2=A0 0x07ff >>>> +/* Reserved */ >>>> +#define VIRTIO_MMIO_MSI_STATUS_RESERVED=C2=A0=C2=A0=C2=A0 0x7800 >>>> + >>>> +#define VIRTIO_MMIO_MSI_CMD_UPDATE=C2=A0=C2=A0=C2=A0 0x1 >>> >>> >>> I believe we need a command to read the number of vectors supported=20 >>> by the device, or 2048 is assumed to be a fixed size here? >> >> For not bringing much complexity, we proposed vector per queue and=20 >> fixed relationship between events and vectors. > > > It's a about the number of MSIs not the mapping between queues to=20 > MSIs.And it looks to me it won't bring obvious complexity, just need a=20 > register to read the #MSIs. Device implementation may stick to a fixed=20 > size. Based on that assumption, the device supports #MSIs =3D #queues + #config.= =20 Then driver need not read the register. We're trying to make such kind of agreement on spec level. > > Having few pages for a device that only have one queue is kind of a=20 > waste. Could I ask what's the meaning of few pages here? BTW, we didn't define=20 MSIx-like tables for virtio-mmio. Thanks, Jing > > Thanks > > >> >> >> So the number of vectors supported by device is equal to the total=20 >> number of vqs and config. >> >> We will try to explicitly highlight this point in spec for later=20 >> version. >> >> >> Thanks! >> >> Jing >> >>> >>> --------------------------------------------------------------------- >>> To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org >>> For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org >>> >> > --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org