Re: [PATCH v3] virtio-scsi: Send "REPORTED LUNS CHANGED" sense data upon disk hotplug events.

[Venu Busireddy <venu.busireddy@oracle.com>]

On 2022-10-07 06:55:15 -0400, Paolo Bonzini wrote:
> Il gio 6 ott 2022, 15:25 Venu Busireddy <venu.busireddy@oracle.com> ha
> scritto:
> 
> > I do see that the Solaris driver does send the 0x1a command during
> > the initialization, perhaps (?) seeking the value of UA_INTLCK_CTRL.
> > Since QEMU currently does not support it, QEMU sends back a
> > key/asc/ascq=0x05/0x24/0x00 response, indicating that 0x1a is an Illegal
> > Request.
> 
> 
> What is your QEMU command line and what is the full CDB (apart from 0x1a)?
> 
> I am assuming that the Solaris driver does not handle that
> > response well (I still don't have access to the source code to verify
> > that), confuses itself about the value of UA_INTLCK_CTRL, and hence does
> > not handle the response to the REPORT_LUNS command correctly.
> 
> 
> No this has nothing to do with what's happening. The most likely reason for
> the bug IMO is simple: the event is causing the driver to send the REPORT
> LUNS command, but it does so in a way that does not handle the unit
> attention when it is reported.

I had a developer with access to the Solaris code review how the response
to REPORT_LUNS is being handled. And they do see that the response to
REPORT_LUNS is mishandled.

With the fix proposed in v4, and fixing the handling of REPORT_LUNS
on the Solaris side, we believe we will have a complete working
solution. Therefore, I believe we can conclude this thread on v3.
Do you agree?

Venu

> 
> Maybe the
> > Solaris driver assumes that QEMU will retain the unit attention condition
> > (UA_INTLCK_CTRL = 10b?), and will respond with a REPORTED_LUNS_CHANGED
> > for a subsequent command?
> >
> > Based on your confirmation that we want to handle the REPORT_LUNS command
> > as if UA_INTLCK_CTRL is set to 0, I will proceed with the assumption
> > that the Solaris driver is at fault, and will work with the Solaris
> > driver folks.
> >
> > In the meantime, as you suggested, I will post v4 with the bus unit
> > attention mechanism implemented. We still need that.
> >
> > Venu
> >
> >