[Qemu-devel] Re: [PATCH master+0.12] pci: irq_state vmstate breakage

["Michael S. Tsirkin" <mst@redhat.com>]

On Sun, May 09, 2010 at 08:07:14PM +0200, Juan Quintela wrote:
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
> > Code for saving irq_state got vm_state
> > macros wrong, passing in the wrong parameter.
> > As a result, we both saved a wrong value
> > and restored it to a wrong offset.
> >
> > This leads to device and bus irq counts getting
> > out of sync, which in turn leads to interrupts getting lost or
> > never cleared, such as
> > https://bugzilla.redhat.com/show_bug.cgi?id=588133
> >
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> 
> Acked-by: Juan Quintela <quintela@redhat.com>
> 
> Code is "obviously" wrong (TM).  I didn't catch it when it was
> introduced.  How can it ever have worked since that commit?

irq_state is often 0, that's why.

> > ---
> >
> > Juan, could you please take a look at this patch?
> > I managed to catch this bug by looking at
> > a savevm image which already has a wrong value,
> > but I could not reproduce it locally so I don't know
> > for sure whether patch is enough, or there are other bugs.
> >
> > Anthony, this is a regression introduced in
> > eea4acfa5c1ef26439a718375475fe468b7f2fba
> > so we need the fix on 0.12 branch as well.
> >
> >  hw/pci.c |    4 ++--
> >  1 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/pci.c b/hw/pci.c
> > index 95bfa3d..5452b86 100644
> > --- a/hw/pci.c
> > +++ b/hw/pci.c
> > @@ -325,7 +325,7 @@ static VMStateInfo vmstate_info_pci_config = {
> >  
> >  static int get_pci_irq_state(QEMUFile *f, void *pv, size_t size)
> >  {
> > -    PCIDevice *s = container_of(pv, PCIDevice, config);
> > +    PCIDevice *s = container_of(pv, PCIDevice, irq_state);
> >      uint32_t irq_state[PCI_NUM_PINS];
> >      int i;
> >      for (i = 0; i < PCI_NUM_PINS; ++i) {
> > @@ -347,7 +347,7 @@ static int get_pci_irq_state(QEMUFile *f, void *pv, size_t size)
> >  static void put_pci_irq_state(QEMUFile *f, void *pv, size_t size)
> >  {
> >      int i;
> > -    PCIDevice *s = container_of(pv, PCIDevice, config);
> > +    PCIDevice *s = container_of(pv, PCIDevice, irq_state);
> >  
> >      for (i = 0; i < PCI_NUM_PINS; ++i) {
> >          qemu_put_be32(f, pci_irq_state(s, i));