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Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM comm
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication |
Date: |
Fri, 15 Dec 2017 12:37:44 +0000 |
User-agent: |
Mutt/1.9.1 (2017-09-22) |
On Fri, Dec 15, 2017 at 06:33:14PM +0800, Wei Wang wrote:
> On 12/14/2017 11:06 PM, Stefan Hajnoczi wrote:
> > On Wed, Dec 13, 2017 at 10:59:10PM +0200, Michael S. Tsirkin wrote:
> > > > * VHOST_USER_SET_VRING_KICK
> > > >
> > > > Set up vring kick doorbell (unless bit 8 is set) before sending
> > > > VHOST_USER_SET_VRING_KICK to the guest.
> > > But guest can't use it, now can it?
> > >
> > > What guest needs is a mapping to interrupts.
> > ...
> > > > * VHOST_USER_SET_VRING_CALL
> > > >
> > > > Set up the vring call doorbell (unless bit 8 is set) before sending
> > > > VHOST_USER_SET_VRING_CALL to the guest.
> > > Same here. what guest needs is mapping from io to notifications,
> > > right?
> > The PCI device should contain a BAR with doorbell registers. I don't
> > think a fancy mapping is necessary, instead the device spec should
> > define the BAR layout.
> >
> > When the guest vhost-user slave receives this message it knows it can
> > now begin using the doorbell register.
>
> Not really. A doorbell will cause an interrupt to be injected to the master
> device driver, which is not ready to work at that time. The slave driver
> isn't expected to use the doorbell until the master is ready by sending the
> last message VHOST_USER_SET_VHOST_PCI to link UP the slave device.
>
> So I think passing the fd msg to guest doesn't have a value in terms of
> functionality.
The new VHOST_USER_SET_VHOST_PCI device message is something you defined
in this patch series. This email sub-thread is about the vhost-user
protocol specification as it exist today.
The VHOST_USER_SET_VRING_CALL is the message that allows the guest to
begin using the doorbell when VHOST_USER_F_PROTOCOL_FEATURES wasn't
negotiated (i.e. the vring is enabled right away).
Stefan
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- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, (continued)
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Stefan Hajnoczi, 2017/12/11
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Wang, Wei W, 2017/12/11
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Stefan Hajnoczi, 2017/12/12
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Wei Wang, 2017/12/13
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Stefan Hajnoczi, 2017/12/13
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Michael S. Tsirkin, 2017/12/13
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Stefan Hajnoczi, 2017/12/13
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Michael S. Tsirkin, 2017/12/13
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Stefan Hajnoczi, 2017/12/14
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Wei Wang, 2017/12/15
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication,
Stefan Hajnoczi <=
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Maxime Coquelin, 2017/12/13
- Re: [Qemu-devel] [virtio-dev] Re: [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Stefan Hajnoczi, 2017/12/14
- Re: [Qemu-devel] [virtio-dev] Re: [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Michael S. Tsirkin, 2017/12/14
- Re: [Qemu-devel] [virtio-dev] Re: [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Maxime Coquelin, 2017/12/14
- Re: [Qemu-devel] [virtio-dev] Re: [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Michael S. Tsirkin, 2017/12/14
- Re: [Qemu-devel] [virtio-dev] Re: [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Maxime Coquelin, 2017/12/14
- Re: [Qemu-devel] [virtio-dev] Re: [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Stefan Hajnoczi, 2017/12/14
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Wei Wang, 2017/12/14
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Stefan Hajnoczi, 2017/12/14
- Re: [Qemu-devel] [virtio-dev] [PATCH v3 0/7] Vhost-pci for inter-VM communication, Wei Wang, 2017/12/15