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vfio: fix sub-page bar after cpr

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Regions for sub-page BARs are normally mapped here, in response to the
guest writing to PCI config space:

  vfio_pci_write_config()
    pci_default_write_config()
      pci_update_mappings()
        memory_region_add_subregion()
    vfio_sub_page_bar_update_mapping()
      ... vfio_dma_map()

However, after CPR, the guest does not reconfigure the device and the
code path above is not taken.  To fix, in vfio_cpr_pci_post_load, call
vfio_sub_page_bar_update_mapping for each sub-page BAR with a valid
address.

Fixes: 7e9f214113 ("vfio/container: restore DMA vaddr")

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Link: https://lore.kernel.org/qemu-devel/1752520890-223356-1-git-send-email-steven.sistare@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
This commit is contained in:
Steve Sistare 2025-07-14 12:21:30 -07:00 • committed by Cédric Le Goater
parent 1dc1220fbd
commit 9751377c3a
3 changed files with 17 additions and 0 deletions
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2
hw/vfio/cpr.c
View file

@ -116,6 +116,8 @@ static int vfio_cpr_pci_post_load(void *opaque, int version_id)
PCIDevice *pdev = &vdev->pdev;
int nr_vectors;
vfio_sub_page_bar_update_mappings(vdev);
if (msix_enabled(pdev)) {
vfio_pci_msix_set_notifiers(vdev);
nr_vectors = vdev->msix->entries;

14
hw/vfio/pci.c
View file

@ -2824,6 +2824,20 @@ static int vfio_pci_load_config(VFIODevice *vbasedev, QEMUFile *f)
return ret;
}
void vfio_sub_page_bar_update_mappings(VFIOPCIDevice *vdev)
{
PCIDevice *pdev = &vdev->pdev;
int page_size = qemu_real_host_page_size();
int bar;
for (bar = 0; bar < PCI_ROM_SLOT; bar++) {
PCIIORegion *r = &pdev->io_regions[bar];
if (r->addr != PCI_BAR_UNMAPPED && r->size > 0 && r->size < page_size) {
vfio_sub_page_bar_update_mapping(pdev, bar);
}
}
}
static VFIODeviceOps vfio_pci_ops = {
.vfio_compute_needs_reset = vfio_pci_compute_needs_reset,
.vfio_hot_reset_multi = vfio_pci_hot_reset_multi,

1
hw/vfio/pci.h
View file

@ -219,6 +219,7 @@ void vfio_pci_write_config(PCIDevice *pdev,
uint64_t vfio_vga_read(void *opaque, hwaddr addr, unsigned size);
void vfio_vga_write(void *opaque, hwaddr addr, uint64_t data, unsigned size);
void vfio_sub_page_bar_update_mappings(VFIOPCIDevice *vdev);
bool vfio_opt_rom_in_denylist(VFIOPCIDevice *vdev);
bool vfio_config_quirk_setup(VFIOPCIDevice *vdev, Error **errp);
void vfio_vga_quirk_setup(VFIOPCIDevice *vdev);