Re: [Qemu-devel] [PATCH 2/2] pcie_aer: clear cmask for Advanced Error Interrupt Message Number

[Jason Baron <jbaron@redhat.com>]

On Fri, Aug 31, 2012 at 06:35:13PM +0300, Michael S. Tsirkin wrote:
> On Fri, Aug 31, 2012 at 10:45:52AM -0400, Jason Baron wrote:
> > On Fri, Aug 31, 2012 at 11:42:27AM +0300, Michael S. Tsirkin wrote:
> > > Some minor nits below. If you dont get to it I will tweak this patch
> > > when I apply it early next week.
> > > 
> > > On Thu, Aug 30, 2012 at 01:51:15PM -0400, Jason Baron wrote:
> > > > The Advanced Error Interrupt Message Number (bits 31:27 of the Root
> > > > Error Status Register) is updated when the number of msi messages assigned to a
> > > > device changes. Migration of windows 7 on q35 chipset failed because the check
> > > > in get_pci_config_device() fails due to wmask being set on these bits.
> > > 
> > > I think you actually mean 'not being set on these bits'?
> > > 
> > 
> > No, the check is:
> > 
> > static int get_pci_config_device(QEMUFile *f, void *pv, size_t size)
> > {
> >     PCIDevice *s = container_of(pv, PCIDevice, config);
> >     uint8_t *config;
> >     int i;
> > 
> >     assert(size == pci_config_size(s));
> >     config = g_malloc(size);
> > 
> >     qemu_get_buffer(f, config, size);
> >     for (i = 0; i < size; ++i) {
> >         if ((config[i] ^ s->config[i]) &
> >             s->cmask[i] & ~s->wmask[i] & ~s->w1cmask[i]) {
> >             g_free(config);
> >             return -EINVAL;
> >         }
> >     }
> > .....
> > 
> > So because cmask is set and these bits differ in config space (due to
> > them being updated before migration), the migration aborts.
> 
> Ah so you mean 'cmask being set' - not wmask as you wrote.
> 

Sorry - my mistake, yes I meant 'cmask'. I will fix the changelog in the
re-post.

Thanks,

-Jason