Linux Virtualization - May 2014 - [PATCH 6/6] virtio-scsi: Enable DIF/DIX modes in SCSI host LLD

On Mon, Apr 07, 2014 at 01:56:59AM -0700, Nicholas A. Bellinger
wrote:
> On Mon, 2014-04-07 at 11:45 +0300, Michael S. Tsirkin wrote:
> > On Sun, Apr 06, 2014 at 09:32:09PM +0000, Nicholas A. Bellinger wrote:
> > > From: Nicholas Bellinger <nab at linux-iscsi.org>
> > > 
> > > This patch updates virtscsi_probe() to setup necessary Scsi_Host
> > > level protection resources. (currently hardcoded to 1)
> > > 
> > > It changes virtscsi_add_cmd() to attach outgoing / incoming
> > > protection SGLs preceeding the data payload, and is using the
> > > new virtio_scsi_cmd_req_pi->d[oi],pi_niv field to signal
> > > to signal to vhost/scsi how many prot_sgs to expect.
> > > 
> > > v3 changes:
> > >   - Use VIRTIO_SCSI_F_T10_PI to determine PI or non PI header
(Paolo)
> > > 
> > > v2 changes:
> > >   - Make protection buffer come before data buffer (Paolo)
> > >   - Enable virtio_scsi_cmd_req_pi usage (Paolo)
> > > 
> > > Cc: Paolo Bonzini <pbonzini at redhat.com>
> > > Cc: Michael S. Tsirkin <mst at redhat.com>
> > > Cc: Martin K. Petersen <martin.petersen at oracle.com>
> > > Cc: Christoph Hellwig <hch at lst.de>
> > > Cc: Hannes Reinecke <hare at suse.de>
> > > Cc: Sagi Grimberg <sagig at dev.mellanox.co.il>
> > > Cc: H. Peter Anvin <hpa at zytor.com>
> > > Signed-off-by: Nicholas Bellinger <nab at linux-iscsi.org>
> > 
> > OK but we need to document the new interface in the spec
> > (and incidentially, this will be useful to verify the assumptions
> > made here and on the host side).
> > Could you please submit this proposal to the OASIS Virtio TC
> > for inclusion into the next spec draft?
> > Ideally as a patch against the tex source, but a prose
> > description would do as well.
> 
> Most certainly.  Please give me a bit to follow up on this, as the next
> couple of days are going to be hellishly busy..
Ping.
We really need to get this moving to have the interface reviewed for
the next merge window.

> > The TC meets on a bi-weekly basis, we should be able to ratify
> > this quickly.
> > 
> 
> Aside from that, please consider ACK'ing the vhost specific changes so
> these can make it into v3.15-rc1 code.
> 
> --nab
>

On Wed, 2014-05-07 at 12:13 +0300, Michael S. Tsirkin
wrote:
> On Mon, Apr 07, 2014 at 01:56:59AM -0700, Nicholas A. Bellinger wrote:
> > On Mon, 2014-04-07 at 11:45 +0300, Michael S. Tsirkin wrote:
> > > On Sun, Apr 06, 2014 at 09:32:09PM +0000, Nicholas A. Bellinger
wrote:
> > > > From: Nicholas Bellinger <nab at linux-iscsi.org>
> > > > 
> > > > This patch updates virtscsi_probe() to setup necessary
Scsi_Host
> > > > level protection resources. (currently hardcoded to 1)
> > > > 
> > > > It changes virtscsi_add_cmd() to attach outgoing / incoming
> > > > protection SGLs preceeding the data payload, and is using
the
> > > > new virtio_scsi_cmd_req_pi->d[oi],pi_niv field to signal
> > > > to signal to vhost/scsi how many prot_sgs to expect.
> > > > 
> > > > v3 changes:
> > > >   - Use VIRTIO_SCSI_F_T10_PI to determine PI or non PI
header (Paolo)
> > > > 
> > > > v2 changes:
> > > >   - Make protection buffer come before data buffer (Paolo)
> > > >   - Enable virtio_scsi_cmd_req_pi usage (Paolo)
> > > > 
> > > > Cc: Paolo Bonzini <pbonzini at redhat.com>
> > > > Cc: Michael S. Tsirkin <mst at redhat.com>
> > > > Cc: Martin K. Petersen <martin.petersen at oracle.com>
> > > > Cc: Christoph Hellwig <hch at lst.de>
> > > > Cc: Hannes Reinecke <hare at suse.de>
> > > > Cc: Sagi Grimberg <sagig at dev.mellanox.co.il>
> > > > Cc: H. Peter Anvin <hpa at zytor.com>
> > > > Signed-off-by: Nicholas Bellinger <nab at
linux-iscsi.org>
> > > 
> > > OK but we need to document the new interface in the spec
> > > (and incidentially, this will be useful to verify the assumptions
> > > made here and on the host side).
> > > Could you please submit this proposal to the OASIS Virtio TC
> > > for inclusion into the next spec draft?
> > > Ideally as a patch against the tex source, but a prose
> > > description would do as well.
> > 
> > Most certainly.  Please give me a bit to follow up on this, as the
next
> > couple of days are going to be hellishly busy..
> 
> Ping.
> We really need to get this moving to have the interface reviewed for
> the next merge window.
> 
Hi MST,

So I've finally got some cycles to get back to this code, and wanted to
verify the outstanding items you had previously raised:

- Convert vhost-scsi to be independent of IOV layout using 
  memcpy_fromiovecend. (Does this effect existing non PI virtio-scsi 
  operation..?)
- Report VIRTIO_F_ANY_LAYOUT feature bit to userspace.
- Convert virtio_scsi_cmd_req_pi to bytes field instead of number of 
  iovecs.
- Ensure virtio_scsi_cmd_req_pi is naturally aligned
- Figure out why QEMU is not acking (any) vhost-scsi feature bits

Is there anything else that you'd like to see for an initial merge, or
other issues that need to be addressed with the above..?

--nab

On Mon, May 19, 2014 at 12:07:03PM -0700, Nicholas A. Bellinger
wrote:
> On Wed, 2014-05-07 at 12:13 +0300, Michael S. Tsirkin wrote:
> > On Mon, Apr 07, 2014 at 01:56:59AM -0700, Nicholas A. Bellinger wrote:
> > > On Mon, 2014-04-07 at 11:45 +0300, Michael S. Tsirkin wrote:
> > > > On Sun, Apr 06, 2014 at 09:32:09PM +0000, Nicholas A.
Bellinger wrote:
> > > > > From: Nicholas Bellinger <nab at linux-iscsi.org>
> > > > > 
> > > > > This patch updates virtscsi_probe() to setup necessary
Scsi_Host
> > > > > level protection resources. (currently hardcoded to 1)
> > > > > 
> > > > > It changes virtscsi_add_cmd() to attach outgoing /
incoming
> > > > > protection SGLs preceeding the data payload, and is
using the
> > > > > new virtio_scsi_cmd_req_pi->d[oi],pi_niv field to
signal
> > > > > to signal to vhost/scsi how many prot_sgs to expect.
> > > > > 
> > > > > v3 changes:
> > > > >   - Use VIRTIO_SCSI_F_T10_PI to determine PI or non PI
header (Paolo)
> > > > > 
> > > > > v2 changes:
> > > > >   - Make protection buffer come before data buffer
(Paolo)
> > > > >   - Enable virtio_scsi_cmd_req_pi usage (Paolo)
> > > > > 
> > > > > Cc: Paolo Bonzini <pbonzini at redhat.com>
> > > > > Cc: Michael S. Tsirkin <mst at redhat.com>
> > > > > Cc: Martin K. Petersen <martin.petersen at
oracle.com>
> > > > > Cc: Christoph Hellwig <hch at lst.de>
> > > > > Cc: Hannes Reinecke <hare at suse.de>
> > > > > Cc: Sagi Grimberg <sagig at dev.mellanox.co.il>
> > > > > Cc: H. Peter Anvin <hpa at zytor.com>
> > > > > Signed-off-by: Nicholas Bellinger <nab at
linux-iscsi.org>
> > > > 
> > > > OK but we need to document the new interface in the spec
> > > > (and incidentially, this will be useful to verify the
assumptions
> > > > made here and on the host side).
> > > > Could you please submit this proposal to the OASIS Virtio TC
> > > > for inclusion into the next spec draft?
> > > > Ideally as a patch against the tex source, but a prose
> > > > description would do as well.
> > > 
> > > Most certainly.  Please give me a bit to follow up on this, as
the next
> > > couple of days are going to be hellishly busy..
> > 
> > Ping.
> > We really need to get this moving to have the interface reviewed for
> > the next merge window.
> > 
> 
> Hi MST,
> 
> So I've finally got some cycles to get back to this code, and wanted to
> verify the outstanding items you had previously raised:
> 
> - Convert vhost-scsi to be independent of IOV layout using 
>   memcpy_fromiovecend. (Does this effect existing non PI virtio-scsi 
>   operation..?)
Ideally yes.
> - Report VIRTIO_F_ANY_LAYOUT feature bit to userspace.
> - Convert virtio_scsi_cmd_req_pi to bytes field instead of number of 
>   iovecs.
> - Ensure virtio_scsi_cmd_req_pi is naturally aligned
It turns out other virtio scsi commands aren't aligned?
If true we don't need to make an exception here.
> - Figure out why QEMU is not acking (any) vhost-scsi feature bits
> 
> Is there anything else that you'd like to see for an initial merge, or
> other issues that need to be addressed with the above..?
> 
> --nab
FYI Paolo sent a spec patch for the feature.
Have you seen it?

-- 
MST

Il 19/05/2014 21:07, Nicholas A. Bellinger ha scritto:
> Hi MST,
>
> So I've finally got some cycles to get back to this code, and wanted to
> verify the outstanding items you had previously raised:
>
> - Convert vhost-scsi to be independent of IOV layout using
>   memcpy_fromiovecend. (Does this effect existing non PI virtio-scsi
>   operation..?)
> - Report VIRTIO_F_ANY_LAYOUT feature bit to userspace.
> - Convert virtio_scsi_cmd_req_pi to bytes field instead of number of
>   iovecs.
This is the only item really required, since the bytes field is what 
will be in VIRTIO 1.0.  The other would be nice to have, but not a 
blocker for PI support.
> - Ensure virtio_scsi_cmd_req_pi is naturally aligned
mst already commented on this.
> - Figure out why QEMU is not acking (any) vhost-scsi feature bits
This is a separate bug, isn't it?  It need not block PI support.

Paolo