From: Jason Wang <jasowang@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Zha Bin <zhabin@linux.alibaba.com>,
virtio-dev@lists.oasis-open.org, slp@redhat.com,
jing2.liu@linux.intel.com, linux-kernel@vger.kernel.org,
qemu-devel@nongnu.org, chao.p.peng@linux.intel.com,
gerry@linux.alibaba.com
Subject: Re: [PATCH v2 1/5] virtio-mmio: add notify feature for per-queue
Date: Wed, 12 Feb 2020 16:53:44 +0800 [thread overview]
Message-ID: <d4eb9cde-5d06-3df9-df28-15378a9c6929@redhat.com> (raw)
In-Reply-To: <20200212024158-mutt-send-email-mst@kernel.org>
On 2020/2/12 下午4:18, Michael S. Tsirkin wrote:
> On Wed, Feb 12, 2020 at 11:39:54AM +0800, Jason Wang wrote:
>> On 2020/2/11 下午7:33, Michael S. Tsirkin wrote:
>>> On Mon, Feb 10, 2020 at 05:05:17PM +0800, Zha Bin wrote:
>>>> From: Liu Jiang<gerry@linux.alibaba.com>
>>>>
>>>> The standard virtio-mmio devices use notification register to signal
>>>> backend. This will cause vmexits and slow down the performance when we
>>>> passthrough the virtio-mmio devices to guest virtual machines.
>>>> We proposed to update virtio over MMIO spec to add the per-queue
>>>> notify feature VIRTIO_F_MMIO_NOTIFICATION[1]. It can allow the VMM to
>>>> configure notify location for each queue.
>>>>
>>>> [1]https://lkml.org/lkml/2020/1/21/31
>>>>
>>>> Signed-off-by: Liu Jiang<gerry@linux.alibaba.com>
>>>> Co-developed-by: Zha Bin<zhabin@linux.alibaba.com>
>>>> Signed-off-by: Zha Bin<zhabin@linux.alibaba.com>
>>>> Co-developed-by: Jing Liu<jing2.liu@linux.intel.com>
>>>> Signed-off-by: Jing Liu<jing2.liu@linux.intel.com>
>>>> Co-developed-by: Chao Peng<chao.p.peng@linux.intel.com>
>>>> Signed-off-by: Chao Peng<chao.p.peng@linux.intel.com>
>>> Hmm. Any way to make this static so we don't need
>>> base and multiplier?
>> E.g page per vq?
>>
>> Thanks
> Problem is, is page size well defined enough?
> Are there cases where guest and host page sizes differ?
> I suspect there might be.
Right, so it looks better to keep base and multiplier, e.g for vDPA.
>
> But I also think this whole patch is unproven. Is someone actually
> working on QEMU code to support pass-trough of virtio-pci
> as virtio-mmio for nested guests? What's the performance
> gain like?
I don't know.
Thanks
>
> -- MST
next prev parent reply other threads:[~2020-02-12 8:54 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-10 9:05 [PATCH v2 0/5] virtio mmio specification enhancement Zha Bin
2020-02-10 9:05 ` [PATCH v2 1/5] virtio-mmio: add notify feature for per-queue Zha Bin
2020-02-11 10:50 ` Michael S. Tsirkin
2020-02-11 11:33 ` Michael S. Tsirkin
2020-02-12 3:39 ` Jason Wang
2020-02-12 8:18 ` Michael S. Tsirkin
2020-02-12 8:53 ` Jason Wang [this message]
2020-02-12 9:33 ` Jason Wang
2020-02-12 9:55 ` Michael S. Tsirkin
2020-02-13 3:38 ` Jason Wang
2020-02-10 9:05 ` [PATCH v2 2/5] virtio-mmio: refactor common functionality Zha Bin
2020-02-11 11:19 ` Michael S. Tsirkin
2020-02-12 2:58 ` [virtio-dev] " Liu, Jing2
2020-02-12 7:29 ` Michael S. Tsirkin
2020-02-10 9:05 ` [PATCH v2 3/5] virtio-mmio: create a generic MSI irq domain Zha Bin
2020-02-11 11:16 ` Michael S. Tsirkin
2020-02-12 7:40 ` Michael S. Tsirkin
2020-02-10 9:05 ` [PATCH v2 4/5] virtio-mmio: add MSI interrupt feature support Zha Bin
2020-02-11 3:17 ` Jason Wang
2020-02-11 3:35 ` [virtio-dev] " Liu, Jing2
2020-02-11 4:02 ` Jason Wang
[not found] ` <5522f205-207b-b012-6631-3cc77dde3bfe@linux.intel.com>
2020-02-11 7:40 ` Jason Wang
2020-02-11 11:58 ` Michael S. Tsirkin
2020-02-11 12:04 ` Jason Wang
2020-02-11 12:08 ` Michael S. Tsirkin
2020-02-11 12:18 ` Jason Wang
2020-02-11 14:00 ` Michael S. Tsirkin
2020-02-12 9:03 ` Jason Wang
2020-02-12 9:15 ` Michael S. Tsirkin
[not found] ` <4c19292f-9d25-a859-3dde-6dd5a03fdf0b@linux.intel.com>
2020-02-12 7:33 ` Michael S. Tsirkin
2020-02-12 9:06 ` Jason Wang
2020-02-12 9:16 ` Michael S. Tsirkin
2020-02-13 3:40 ` Jason Wang
2020-02-11 11:21 ` Michael S. Tsirkin
2020-02-11 11:11 ` Michael S. Tsirkin
2020-02-10 9:05 ` [PATCH v2 5/5] x86: virtio-mmio: support virtio-mmio with MSI for x86 Zha Bin
2020-02-11 11:14 ` Michael S. Tsirkin
2020-02-10 11:44 ` [PATCH v2 0/5] virtio mmio specification enhancement Michael S. Tsirkin
2020-02-11 16:05 ` Chao Peng
2020-02-11 10:57 ` Michael S. Tsirkin
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