If ROM bar is missing for any reason, we can fallback to using pdev->rom
to expose the ROM content to the guest. This fixes some passthrough use
cases where the upstream bridge does not have enough address window.
Signed-off-by: Yunxiang Li <Yunxiang.Li@xxxxxxx>
---
drivers/vfio/pci/vfio_pci_config.c | 4 ++++
drivers/vfio/pci/vfio_pci_core.c | 35 +++++++++++++++---------------
drivers/vfio/pci/vfio_pci_rdwr.c | 14 ++++++++++--
3 files changed, 34 insertions(+), 19 deletions(-)
diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
index e41c3a965663e..4c673d842fb35 100644
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -511,6 +511,10 @@ static void vfio_bar_fixup(struct vfio_pci_core_device *vdev)
mask = ~(pci_resource_len(pdev, PCI_ROM_RESOURCE) - 1);
mask |= PCI_ROM_ADDRESS_ENABLE;
*vbar &= cpu_to_le32((u32)mask);
+ } else if (pdev->rom && pdev->romlen) {
+ mask = ~(roundup_pow_of_two(pdev->romlen) - 1);
+ mask |= PCI_ROM_ADDRESS_ENABLE;
+ *vbar &= cpu_to_le32((u32)mask);
} else {
*vbar = 0;
}
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index b49dd9cdc072a..3120c1e9f22cb 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -1049,30 +1049,31 @@ static int vfio_pci_ioctl_get_region_info(struct vfio_pci_core_device *vdev,
break;
case VFIO_PCI_ROM_REGION_INDEX: {
void __iomem *io;
- size_t size;
+ size_t dont_care;
u16 cmd;
info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
info.flags = 0;
+ info.size = 0;
- /* Report the BAR size, not the ROM size */
- info.size = pci_resource_len(pdev, info.index);
- if (!info.size)
- break;
-
- /*
- * Is it really there? Enable memory decode for implicit access
- * in pci_map_rom().
- */
- cmd = vfio_pci_memory_lock_and_enable(vdev);
- io = pci_map_rom(pdev, &size);
- if (io) {
+ if (pci_resource_start(pdev, PCI_ROM_RESOURCE)) {
+ /* Check ROM content is valid. Need to enable memory
+ * decode for ROM access in pci_map_rom().
+ */
+ cmd = vfio_pci_memory_lock_and_enable(vdev);
+ io = pci_map_rom(pdev, &dont_care);
+ if (io) {
+ info.flags = VFIO_REGION_INFO_FLAG_READ;
+ /* Report the BAR size, not the ROM size. */
+ info.size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
+ pci_unmap_rom(pdev, io);
+ }
+ vfio_pci_memory_unlock_and_restore(vdev, cmd);
+ } else if (pdev->rom && pdev->romlen) {
info.flags = VFIO_REGION_INFO_FLAG_READ;
- pci_unmap_rom(pdev, io);
- } else {
- info.size = 0;
+ /* Report BAR size as power of two. */
+ info.size = roundup_pow_of_two(pdev->romlen);
}
- vfio_pci_memory_unlock_and_restore(vdev, cmd);
break;
}
diff --git a/drivers/vfio/pci/vfio_pci_rdwr.c b/drivers/vfio/pci/vfio_pci_rdwr.c
index 4bed9fd5af50f..4ea983cf499d9 100644
--- a/drivers/vfio/pci/vfio_pci_rdwr.c
+++ b/drivers/vfio/pci/vfio_pci_rdwr.c
@@ -243,6 +243,8 @@ ssize_t vfio_pci_bar_rw(struct vfio_pci_core_device *vdev, char __user *buf,
if (pci_resource_start(pdev, bar))
end = pci_resource_len(pdev, bar);
+ else if (bar == PCI_ROM_RESOURCE && pdev->rom && pdev->romlen)
+ end = roundup_pow_of_two(pdev->romlen);
else
return -EINVAL;
@@ -259,7 +261,12 @@ ssize_t vfio_pci_bar_rw(struct vfio_pci_core_device *vdev, char __user *buf,
* excluded range at the end of the actual ROM. This makes
* filling large ROM BARs much faster.
*/
- io = pci_map_rom(pdev, &x_start);
+ if (pci_resource_start(pdev, bar)) {
+ io = pci_map_rom(pdev, &x_start);
+ } else {
+ io = ioremap(pdev->rom, pdev->romlen);
+ x_start = pdev->romlen;
+ }
if (!io)
return -ENOMEM;
x_end = end;
@@ -267,7 +274,10 @@ ssize_t vfio_pci_bar_rw(struct vfio_pci_core_device *vdev, char __user *buf,
done = vfio_pci_core_do_io_rw(vdev, 1, io, buf, pos,
count, x_start, x_end, 0);
- pci_unmap_rom(pdev, io);
+ if (pci_resource_start(pdev, bar))
+ pci_unmap_rom(pdev, io);
+ else
+ iounmap(io);
} else {
done = vfio_pci_core_setup_barmap(vdev, bar);
if (done)
--
2.47.0
