Re: [Xen-devel] [PATCH v3 for 4.5] ioreq-server: handle the lack of a default emulator properly

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

> -----Original Message-----
> From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
> Sent: 02 October 2014 11:28
> To: Paul Durrant
> Cc: Andrew Cooper; xen-devel@xxxxxxxxxxxxx; Keir (Xen.org)
> Subject: RE: [Xen-devel] [PATCH v3 for 4.5] ioreq-server: handle the lack of a
> default emulator properly
> 
> >>> On 02.10.14 at 11:54, <Paul.Durrant@xxxxxxxxxx> wrote:
> >>  -----Original Message-----
> >> From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
> >> Sent: 30 September 2014 10:49
> >> To: Andrew Cooper; Paul Durrant
> >> Cc: xen-devel@xxxxxxxxxxxxx; Keir (Xen.org)
> >> Subject: RE: [Xen-devel] [PATCH v3 for 4.5] ioreq-server: handle the lack
> of a
> >> default emulator properly
> >>
> >> >>> On 30.09.14 at 11:43, <Paul.Durrant@xxxxxxxxxx> wrote:
> >> >>  -----Original Message-----
> >> >> From: Andrew Cooper
> >> >> Sent: 30 September 2014 10:29
> >> >> To: Paul Durrant; xen-devel@xxxxxxxxxxxxx
> >> >> Cc: Keir (Xen.org); Jan Beulich
> >> >> Subject: Re: [Xen-devel] [PATCH v3 for 4.5] ioreq-server: handle the
> lack
> >> of a
> >> >> default emulator properly
> >> >>
> >> >> On 30/09/14 10:18, Paul Durrant wrote:
> >> >> > I started porting QEMU over to use the new ioreq server API and hit
> a
> >> >> > problem with PCI bus enumeration. Because, with my patches,
> QEMU
> >> only
> >> >> > registers to handle config space accesses for the PCI device it
> >> implements
> >> >> > all other attempts by the guest to access 0xcfc go nowhere and this
> was
> >> >> > causing the vcpu to wedge up because nothing was completing the
> I/O.
> >> >> >
> >> >> > This patch introduces an I/O completion handler into the hypervisor
> for
> >> the
> >> >> > case where no ioreq server matches a particular request. Read
> requests
> >> >> are
> >> >> > completed with 0xf's in the data buffer, writes and all other I/O req
> >> types
> >> >> > are ignored.
> >> >> >
> >> >> > Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
> >> >> > Cc: Keir Fraser <keir@xxxxxxx>
> >> >> > Cc: Jan Beulich <jbeulich@xxxxxxxx>
> >> >>
> >> >> One bug, couple of nits.
> >> >>
> >> >> It is probably worth having a sentence in the commit message
> concerning
> >> >> the removal of list_is_singular().
> >> >>
> >> >> > ---
> >> >> > v3: - Fix for backwards string instruction emulation
> >> >> >
> >> >> > v2: - First non-RFC submission
> >> >> >     - Removed warning on unemulated MMIO accesses
> >> >> >
> >> >> >  xen/arch/x86/hvm/hvm.c |   35
> >> ++++++++++++++++++++++++++++++++-
> >> >> --
> >> >> >  1 file changed, 32 insertions(+), 3 deletions(-)
> >> >> >
> >> >> > diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> >> >> > index 5c7e0a4..e6611ed 100644
> >> >> > --- a/xen/arch/x86/hvm/hvm.c
> >> >> > +++ b/xen/arch/x86/hvm/hvm.c
> >> >> > @@ -2386,8 +2386,7 @@ static struct hvm_ioreq_server
> >> >> *hvm_select_ioreq_server(struct domain *d,
> >> >> >      if ( list_empty(&d->arch.hvm_domain.ioreq_server.list) )
> >> >> >          return NULL;
> >> >> >
> >> >> > -    if ( list_is_singular(&d->arch.hvm_domain.ioreq_server.list) ||
> >> >> > -         (p->type != IOREQ_TYPE_COPY && p->type !=
> IOREQ_TYPE_PIO) )
> >> >> > +    if ( p->type != IOREQ_TYPE_COPY && p->type !=
> IOREQ_TYPE_PIO )
> >> >> >          return d->arch.hvm_domain.default_ioreq_server;
> >> >> >
> >> >> >      cf8 = d->arch.hvm_domain.pci_cf8;
> >> >> > @@ -2618,12 +2617,42 @@ bool_t
> >> >> hvm_send_assist_req_to_ioreq_server(struct hvm_ioreq_server *s,
> >> >> >      return 0;
> >> >> >  }
> >> >> >
> >> >> > +static bool_t hvm_complete_assist_req(ioreq_t *p)
> >> >> > +{
> >> >> > +    switch (p->type)
> >> >>
> >> >> Style: ( p-> type )
> >> >>
> >> >
> >> > <Sigh> Yes, missed that one.
> >>
> >> And I can fix that while committing...
> >>
> >
> > BTW, can I take that as an ack?
> 
> Sure, but is that still relevant considering that the patch got committed
> already?
> 

Ok, that's fine then :-) I just pulled staging and didn't see it. I'll check 
again.

  Paul

> Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel