From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: Parav Pandit <parav@nvidia.com>,
virtio-dev@lists.oasis-open.org, cohuck@redhat.com,
virtio-comment@lists.oasis-open.org, shahafs@nvidia.com,
Satananda Burla <sburla@marvell.com>
Subject: [virtio-comment] Re: [virtio-dev] [PATCH 08/11] transport-pci: Introduce virtio extended capability
Date: Tue, 11 Apr 2023 06:43:54 -0400 [thread overview]
Message-ID: <20230411064333-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <CACGkMEui1ouE8DcXKkWUavToUT+vEP-c640vtw3BJBOSz5YTkw@mail.gmail.com>
On Tue, Apr 11, 2023 at 05:07:11PM +0800, Jason Wang wrote:
> On Tue, Apr 11, 2023 at 3:00 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> >
> > On Tue, Apr 11, 2023 at 10:19:39AM +0800, Jason Wang wrote:
> > > On Mon, Apr 10, 2023 at 6:04 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> > > >
> > > > On Mon, Apr 10, 2023 at 03:16:46PM +0800, Jason Wang wrote:
> > > > > On Mon, Apr 10, 2023 at 2:24 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> > > > > >
> > > > > > On Mon, Apr 10, 2023 at 09:36:17AM +0800, Jason Wang wrote:
> > > > > > > On Fri, Mar 31, 2023 at 7:00 AM Parav Pandit <parav@nvidia.com> wrote:
> > > > > > > >
> > > > > > > > PCI device configuration space for capabilities is limited to only 192
> > > > > > > > bytes shared by many PCI capabilities of generic PCI device and virtio
> > > > > > > > specific.
> > > > > > > >
> > > > > > > > Hence, introduce virtio extended capability that uses PCI Express
> > > > > > > > extended capability.
> > > > > > > > Subsequent patch uses this virtio extended capability.
> > > > > > > >
> > > > > > > > Co-developed-by: Satananda Burla <sburla@marvell.com>
> > > > > > > > Signed-off-by: Parav Pandit <parav@nvidia.com>
> > > > > > >
> > > > > > > Can you explain the differences compared to what I've used to propose?
> > > > > > >
> > > > > > > https://www.mail-archive.com/virtio-dev@lists.oasis-open.org/msg08078.html
> > > > > > >
> > > > > > > This can save time for everybody.
> > > > > > >
> > > > > > > Thanks
> > > > > >
> > > > > > BTW another advantage of extended capabilities is - these are actually
> > > > > > cheaper to access from a VM than classic config space.
> > > > >
> > > > > Config space/BAR is allowed by both of the proposals or anything I missed?
> > > > >
> > > > > >
> > > > > >
> > > > > > Several points
> > > > > > - I don't like it that yours is 32 bit. We do not need 2 variants just
> > > > > > make it all 64 bit
> > > > >
> > > > > That's fine.
> > > > >
> > > > > > - We need to document that if driver does not scan extended capbilities it will not find them.
> > > > >
> > > > > This is implicit since I remember we don't have such documentation for
> > > > > pci capability, anything makes pcie special?
> > > >
> > > > yes - the fact that there are tons of existing drivers expecting
> > > > everything in standard space.
> > > >
> > > >
> > > > > > And existing drivers do not scan them. So what is safe
> > > > > > to put there? vendor specific? extra access types?
> > > > >
> > > > > For PASID at least, since it's a PCI-E feature, vendor specific should
> > > > > be fine. Not sure about legacy MMIO then.
> > > > >
> > > > > > Can we make scanning these mandatory in future drivers? future devices?
> > > > > > I guess we can add a feature bit to flag that.
> > > > >
> > > > > For PASID, it doesn't need this, otherwise we may duplicate transport
> > > > > specific features.
> > > >
> > > > i don't get it. what does PASID have to do with it?
> > >
> > > My proposal is to allow PASID capability to be placed on top.
> >
> > Assuming you mean a patch applied on top of this one.
> >
> > > So what
> > > I meant is:
> > >
> > > if the driver needs to use PASID, it needs to scan extend capability
> > >
> > > So it is only used for future drivers. I think this applies to legacy
> > > MMIO as well.
> >
> > sure
> >
> > > > A new feature will allow clean split at least:
> > > > we make any new features and new devices that expect
> > > > express capability depend on this new feature bit.
> > > >
> > > > > > Is accessing these possible from bios?
> > > > >
> > > > > Not at least for the two use cases now PASID or legacy MMIO.
> > > >
> > > > can't parse english here. what does this mean?
> > >
> > > I meant, it depends on the capability semantics. Both PASID and legacy
> > > MMIO don't need to be accessed by BIOS. We can't change legacy BIOS to
> > > use legacy MMIO bars.
> > >
> > > Thanks
> >
> > makes sense.
> >
> >
> > now, imagine someone building a new device. if existing drivers are not
> > a concern, it is possible to move capabilities all to extended space. is
> > that possible while keeping the bios working?
>
> This is possible but I'm not sure it's worthwhile. What happens if the
> device puts all capabilities in the extended space but the bios can't
> scan there?
that's my question. can seabios access extended caps?
> We can place them at both but it then doesn't address the
> out of space issue. Things will be easier if we allow new
> features/capabilities to be placed on the extended space.
>
> Thanks
>
> >
> > > >
> > > >
> > > > > >
> > > > > > So I like this one better as a basis - care reviewing it and adding
> > > > > > stuff?
> > > > >
> > > > > There are very few differences and I will have a look.
> > > > >
> > > > > Thanks
> > > > >
> > > > > >
> > > > > > --
> > > > > > MST
> > > > > >
> > > >
> >
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next prev parent reply other threads:[~2023-04-11 10:44 UTC|newest]
Thread overview: 199+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-30 22:58 [virtio-comment] [PATCH 00/11] Introduce transitional mmr pci device Parav Pandit
2023-03-30 22:58 ` [virtio-comment] [PATCH 01/11] transport-pci: Use lowecase alphabets Parav Pandit
2023-03-30 22:58 ` [virtio-comment] [PATCH 02/11] transport-pci: Move transitional device id to legacy section Parav Pandit
2023-03-31 6:43 ` [virtio-comment] " Michael S. Tsirkin
2023-03-31 21:24 ` [virtio-comment] " Parav Pandit
2023-04-02 7:54 ` [virtio-comment] " Michael S. Tsirkin
2023-04-03 14:42 ` [virtio-comment] " Parav Pandit
2023-04-03 14:50 ` [virtio-comment] " Michael S. Tsirkin
2023-04-03 14:58 ` [virtio-comment] " Parav Pandit
2023-04-03 15:14 ` [virtio-comment] " Michael S. Tsirkin
2023-03-30 22:58 ` [virtio-comment] [PATCH 03/11] transport-pci: Split notes of PCI Device Layout Parav Pandit
2023-03-30 22:58 ` [virtio-comment] [PATCH 04/11] transport-pci: Rename and move legacy PCI Device layout section Parav Pandit
2023-03-30 22:58 ` [virtio-comment] [PATCH 05/11] introduction: Add missing helping verb Parav Pandit
2023-03-30 22:58 ` [virtio-comment] [PATCH 06/11] introduction: Introduce transitional MMR interface Parav Pandit
2023-04-07 9:17 ` [virtio-comment] " Michael S. Tsirkin
2023-03-30 22:58 ` [virtio-comment] [PATCH 07/11] transport-pci: Introduce transitional MMR device id Parav Pandit
2023-04-04 7:28 ` [virtio-comment] " Michael S. Tsirkin
2023-04-04 16:08 ` Parav Pandit
2023-04-07 12:03 ` Michael S. Tsirkin
2023-04-07 15:18 ` Parav Pandit
2023-04-07 15:51 ` Michael S. Tsirkin
2023-04-09 3:15 ` Parav Pandit
2023-04-10 10:18 ` Michael S. Tsirkin
2023-04-10 14:34 ` Parav Pandit
2023-04-10 19:58 ` Michael S. Tsirkin
2023-04-10 20:16 ` Parav Pandit
2023-04-07 8:37 ` Michael S. Tsirkin
2023-03-30 22:58 ` [virtio-comment] [PATCH 08/11] transport-pci: Introduce virtio extended capability Parav Pandit
2023-04-04 7:35 ` [virtio-comment] " Michael S. Tsirkin
2023-04-04 7:54 ` Cornelia Huck
2023-04-04 12:43 ` Michael S. Tsirkin
2023-04-04 13:19 ` Cornelia Huck
2023-04-04 14:37 ` Michael S. Tsirkin
2023-04-10 16:21 ` Parav Pandit
2023-04-10 19:49 ` Michael S. Tsirkin
2023-04-10 19:57 ` [virtio-comment] " Parav Pandit
2023-04-10 20:02 ` [virtio-comment] " Michael S. Tsirkin
2023-04-11 8:39 ` Cornelia Huck
2023-04-04 21:18 ` [virtio-comment] " Parav Pandit
2023-04-05 5:10 ` [virtio-comment] " Michael S. Tsirkin
2023-04-05 13:16 ` [virtio-comment] " Parav Pandit
2023-04-07 8:15 ` [virtio-comment] " Michael S. Tsirkin
2023-04-10 1:36 ` [virtio-comment] Re: [virtio-dev] " Jason Wang
2023-04-10 6:24 ` Michael S. Tsirkin
2023-04-10 7:16 ` Jason Wang
2023-04-10 10:04 ` Michael S. Tsirkin
2023-04-11 2:19 ` Jason Wang
2023-04-11 7:00 ` Michael S. Tsirkin
2023-04-11 9:07 ` Jason Wang
2023-04-11 10:43 ` Michael S. Tsirkin [this message]
2023-04-11 13:59 ` [virtio-comment] " Parav Pandit
2023-04-11 14:11 ` [virtio-comment] " Michael S. Tsirkin
2023-04-11 13:47 ` Parav Pandit
2023-04-11 14:02 ` Michael S. Tsirkin
2023-04-11 14:07 ` Parav Pandit
2023-04-11 14:10 ` Michael S. Tsirkin
2023-04-11 14:30 ` Parav Pandit
2023-04-10 17:54 ` Parav Pandit
2023-04-10 17:58 ` Parav Pandit
2023-04-11 3:28 ` Jason Wang
2023-04-11 19:01 ` [virtio-comment] " Parav Pandit
2023-04-11 21:25 ` [virtio-comment] " Michael S. Tsirkin
2023-04-12 0:40 ` [virtio-comment] " Parav Pandit
2023-04-12 2:56 ` [virtio-comment] " Michael S. Tsirkin
2023-04-12 4:07 ` Jason Wang
2023-04-12 4:20 ` Michael S. Tsirkin
2023-04-12 4:53 ` Jason Wang
2023-04-12 5:25 ` Michael S. Tsirkin
2023-04-12 5:37 ` Jason Wang
2023-04-13 17:03 ` Michael S. Tsirkin
2023-04-12 4:04 ` Jason Wang
2023-04-12 4:13 ` [virtio-comment] " Parav Pandit
2023-04-12 4:20 ` [virtio-comment] " Michael S. Tsirkin
2023-04-12 4:55 ` Jason Wang
2023-05-19 6:10 ` [virtio-comment] " Michael S. Tsirkin
2023-05-19 21:02 ` [virtio-comment] " Parav Pandit
2023-05-21 5:57 ` [virtio-comment] " Michael S. Tsirkin
2023-05-21 13:24 ` [virtio-comment] " Parav Pandit
2023-05-21 14:34 ` [virtio-comment] " Michael S. Tsirkin
2023-03-30 22:58 ` [virtio-comment] [PATCH 09/11] transport-pci: Describe PCI MMR dev config registers Parav Pandit
2023-04-07 8:55 ` [virtio-comment] " Michael S. Tsirkin
2023-04-10 1:33 ` Jason Wang
2023-04-10 6:14 ` Michael S. Tsirkin
2023-04-10 6:20 ` Jason Wang
2023-04-10 6:39 ` Michael S. Tsirkin
2023-04-10 7:20 ` Jason Wang
2023-04-10 10:06 ` Michael S. Tsirkin
2023-04-11 2:13 ` Jason Wang
2023-04-11 7:04 ` Michael S. Tsirkin
2023-04-11 9:01 ` Jason Wang
[not found] ` <CALBs2cXURMEzCGnULicXbsBfwnKE5cZOz=M-_hhFCXZ=Lqb9Nw@mail.gmail.com>
2023-04-11 10:39 ` Michael S. Tsirkin
2023-04-11 10:42 ` Michael S. Tsirkin
2023-04-12 3:58 ` Jason Wang
2023-04-12 4:15 ` Michael S. Tsirkin
2023-04-12 4:51 ` Jason Wang
2023-04-12 5:01 ` Parav Pandit
2023-04-12 5:14 ` Jason Wang
2023-04-12 5:30 ` Parav Pandit
2023-04-12 5:38 ` Jason Wang
2023-04-12 5:55 ` Parav Pandit
2023-04-12 6:15 ` Jason Wang
2023-04-12 14:23 ` Parav Pandit
2023-04-13 1:48 ` Jason Wang
2023-04-13 3:31 ` Parav Pandit
2023-04-13 5:14 ` Jason Wang
2023-04-13 17:19 ` Michael S. Tsirkin
2023-04-13 19:39 ` Parav Pandit
2023-04-14 3:09 ` Jason Wang
2023-04-14 3:18 ` Parav Pandit
2023-04-14 3:37 ` Jason Wang
2023-04-14 3:51 ` Parav Pandit
2023-04-14 7:05 ` Michael S. Tsirkin
2023-04-17 3:22 ` Jason Wang
2023-04-17 17:23 ` Parav Pandit
2023-04-17 20:26 ` Michael S. Tsirkin
2023-04-17 20:28 ` Parav Pandit
2023-04-18 0:36 ` Jason Wang
2023-04-18 1:30 ` Parav Pandit
2023-04-18 11:58 ` Michael S. Tsirkin
2023-04-18 12:09 ` Parav Pandit
2023-04-18 12:30 ` Michael S. Tsirkin
2023-04-18 12:36 ` Parav Pandit
2023-04-18 1:01 ` Jason Wang
2023-04-18 1:48 ` Parav Pandit
2023-04-13 17:24 ` Parav Pandit
2023-04-13 21:02 ` Michael S. Tsirkin
2023-04-13 21:08 ` Parav Pandit
2023-04-14 2:36 ` Jason Wang
2023-04-14 2:43 ` Parav Pandit
2023-04-14 6:57 ` Michael S. Tsirkin
2023-04-16 13:41 ` Parav Pandit
2023-04-16 20:44 ` Michael S. Tsirkin
2023-04-17 16:59 ` Parav Pandit
2023-04-18 1:09 ` Jason Wang
2023-04-18 1:37 ` Parav Pandit
2023-04-14 6:58 ` Michael S. Tsirkin
2023-04-14 3:08 ` Jason Wang
2023-04-14 3:13 ` Parav Pandit
2023-04-14 3:18 ` Jason Wang
2023-04-14 3:22 ` Parav Pandit
2023-04-14 3:29 ` Jason Wang
2023-04-11 13:57 ` Parav Pandit
2023-04-12 4:33 ` Michael S. Tsirkin
2023-03-30 22:58 ` [virtio-comment] [PATCH 10/11] transport-pci: Use driver notification PCI capability Parav Pandit
2023-04-12 4:31 ` [virtio-comment] " Michael S. Tsirkin
2023-04-12 4:37 ` [virtio-comment] " Parav Pandit
2023-04-12 4:43 ` [virtio-comment] " Michael S. Tsirkin
2023-04-12 4:48 ` [virtio-comment] " Parav Pandit
2023-04-12 5:02 ` [virtio-comment] " Michael S. Tsirkin
2023-04-12 5:06 ` Parav Pandit
2023-04-12 5:17 ` Michael S. Tsirkin
2023-04-12 5:24 ` Parav Pandit
2023-04-12 5:27 ` Michael S. Tsirkin
2023-03-30 22:58 ` [virtio-comment] [PATCH 11/11] conformance: Add transitional MMR interface conformance Parav Pandit
2023-03-31 7:03 ` [virtio-comment] Re: [PATCH 00/11] Introduce transitional mmr pci device Michael S. Tsirkin
2023-03-31 21:43 ` Parav Pandit
2023-04-03 14:53 ` Michael S. Tsirkin
2023-04-03 14:57 ` [virtio-comment] " Parav Pandit
2023-04-03 15:06 ` [virtio-comment] " Michael S. Tsirkin
2023-04-03 15:16 ` [virtio-comment] " Parav Pandit
2023-04-03 15:23 ` [virtio-comment] " Michael S. Tsirkin
2023-04-03 15:34 ` Michael S. Tsirkin
2023-04-03 15:47 ` [virtio-comment] " Parav Pandit
2023-04-03 17:28 ` [virtio-comment] " Michael S. Tsirkin
2023-04-03 17:35 ` Parav Pandit
2023-04-03 17:39 ` Michael S. Tsirkin
2023-04-03 15:36 ` Parav Pandit
2023-04-03 17:16 ` Michael S. Tsirkin
2023-04-03 17:29 ` Parav Pandit
2023-04-03 18:02 ` Michael S. Tsirkin
2023-04-03 20:25 ` Parav Pandit
2023-04-03 21:04 ` Michael S. Tsirkin
2023-04-03 22:00 ` Parav Pandit
2023-04-07 9:35 ` Michael S. Tsirkin
2023-04-10 1:52 ` Jason Wang
2023-04-03 14:45 ` [virtio-comment] " Stefan Hajnoczi
2023-04-03 14:53 ` Parav Pandit
2023-04-03 17:48 ` Michael S. Tsirkin
2023-04-03 19:11 ` Stefan Hajnoczi
2023-04-03 20:03 ` Michael S. Tsirkin
2023-04-03 19:48 ` Parav Pandit
2023-04-03 20:02 ` Michael S. Tsirkin
2023-04-03 20:42 ` Parav Pandit
2023-04-03 21:14 ` Michael S. Tsirkin
2023-04-03 22:08 ` Parav Pandit
2023-04-03 19:10 ` Stefan Hajnoczi
2023-04-03 20:27 ` Parav Pandit
2023-04-04 14:30 ` Stefan Hajnoczi
2023-04-12 4:48 ` [virtio-comment] " Michael S. Tsirkin
2023-04-12 4:52 ` [virtio-comment] " Parav Pandit
2023-04-12 5:12 ` [virtio-comment] " Michael S. Tsirkin
2023-04-12 5:15 ` Parav Pandit
2023-04-12 5:23 ` Michael S. Tsirkin
2023-04-12 5:39 ` Parav Pandit
2023-04-12 6:02 ` Parav Pandit
2023-04-12 5:10 ` [virtio-comment] Re: [virtio-dev] " Halil Pasic
2023-04-25 2:42 ` [virtio-comment] " Parav Pandit
2023-05-02 7:17 ` David Edmondson
2023-05-02 13:54 ` Parav Pandit
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