Re: [Qemu-devel] [PATCHv3 08/13] qemu: add support for resizing regions

Michael S. Tsirkin
2009-06-10T10:49:24Z

On Tue, Jun 09, 2009 at 02:36:21PM -0300, Glauber Costa wrote:
> On Fri, Jun 05, 2009 at 01:23:55PM +0300, Michael S. Tsirkin wrote:
> > Make it possible to resize PCI regions. This will be used by virtio
> > with MSI-X, where the region size depends on whether MSI-X is enabled,
> > and can change across load/save.
> >
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> > hw/pci.c | 54 ++++++++++++++++++++++++++++++++++++------------------
> > hw/pci.h | 3 +++
> > 2 files changed, 39 insertions(+), 18 deletions(-)
> >
> > diff --git a/hw/pci.c b/hw/pci.c
> > index ed011b5..042a216 100644
> > --- a/hw/pci.c
> > +++ b/hw/pci.c
> > @@ -392,6 +392,41 @@ void pci_register_io_region(PCIDevice *pci_dev, int region_num,
> > *(uint32_t *)(pci_dev->wmask + addr) = cpu_to_le32(wmask);
> > }
> >
> > +static void pci_unmap_region(PCIDevice *d, PCIIORegion *r)
> > +{
> > + if (r->addr == -1)
> > + return;
> > + if (r->type & PCI_ADDRESS_SPACE_IO) {
> > + int class;
> > + /* NOTE: specific hack for IDE in PC case:
> > + only one byte must be mapped. */
> > + class = pci_get_word(d->config + PCI_CLASS_DEVICE);
> > + if (class == 0x0101 && r->size == 4) {
> > + isa_unassign_ioport(r->addr + 2, 1);
> > + } else {
> > + isa_unassign_ioport(r->addr, r->size);
> > + }
> > + } else {
> > + cpu_register_physical_memory(pci_to_cpu_addr(r->addr),
> > + r->size,
> > + IO_MEM_UNASSIGNED);
> > + qemu_unregister_coalesced_mmio(r->addr, r->size);
> > + }
> > +}
> > +
> this is a good cleanup...
>
> > +void pci_resize_io_region(PCIDevice *pci_dev, int region_num,
> > + uint32_t size)
> > +{
> > +
> > + PCIIORegion *r = &pci_dev->io_regions[region_num];
> > + if (r->size == size)
> > + return;
> > + r->size = size;
> > + pci_unmap_region(pci_dev, r);
> > + r->addr = -1;
> > + pci_update_mappings(pci_dev);
> > +}
> > +
> but the only user of this one seem to be commented out, and later removed.
> Why is this needed?
>

This was the missing bit:

Set correct size for msi-x memory region when loading the device.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index 589fbb1..f657364 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -133,6 +133,8 @@ static int virtio_pci_load_config(void * opaque, QEMUFile *f)
return ret;
if (msix_present(&proxy->pci_dev))
qemu_get_be16s(f, &proxy->vdev->config_vector);
+
+ pci_resize_io_region(&proxy->pci_dev, 1, msix_bar_size(&proxy->pci_dev));
return 0;
}

--
MST