[PATCH v2 11/11] vfio/pci: Expose shadow ROM as PCI option ROM

From: Alex Williamson
Date: Fri Feb 12 2016 - 19:03:10 EST


Integrated graphics may have their ROM shadowed at 0xc0000 rather than
implement a PCI option ROM. Make this ROM appear to the user using
the ROM BAR.

Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
---
drivers/vfio/pci/vfio_pci.c | 10 ++++++++--
drivers/vfio/pci/vfio_pci_config.c | 11 ++++++++---
drivers/vfio/pci/vfio_pci_rdwr.c | 9 ++++++---
3 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 74a3752..1ce1d36 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -609,8 +609,14 @@ static long vfio_pci_ioctl(void *device_data,

/* Report the BAR size, not the ROM size */
info.size = pci_resource_len(pdev, info.index);
- if (!info.size)
- break;
+ if (!info.size) {
+ /* Shadow ROMs appear as PCI option ROMs */
+ if (pdev->resource[PCI_ROM_RESOURCE].flags &
+ IORESOURCE_ROM_SHADOW)
+ info.size = 0x20000;
+ else
+ break;
+ }

/* Is it really there? */
io = pci_map_rom(pdev, &size);
diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
index 88dc646..142c533 100644
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -475,14 +475,19 @@ static void vfio_bar_fixup(struct vfio_pci_device *vdev)
bar = (__le32 *)&vdev->vconfig[PCI_ROM_ADDRESS];

/*
- * NB. we expose the actual BAR size here, regardless of whether
- * we can read it. When we report the REGION_INFO for the ROM
- * we report what PCI tells us is the actual ROM size.
+ * NB. REGION_INFO will have reported zero size if we weren't able
+ * to read the ROM, but we still return the actual BAR size here if
+ * it exists (or the shadow ROM space).
*/
if (pci_resource_start(pdev, PCI_ROM_RESOURCE)) {
mask = ~(pci_resource_len(pdev, PCI_ROM_RESOURCE) - 1);
mask |= PCI_ROM_ADDRESS_ENABLE;
*bar &= cpu_to_le32((u32)mask);
+ } else if (pdev->resource[PCI_ROM_RESOURCE].flags &
+ IORESOURCE_ROM_SHADOW) {
+ mask = ~(0x20000 - 1);
+ mask |= PCI_ROM_ADDRESS_ENABLE;
+ *bar &= cpu_to_le32((u32)mask);
} else
*bar = 0;

diff --git a/drivers/vfio/pci/vfio_pci_rdwr.c b/drivers/vfio/pci/vfio_pci_rdwr.c
index 210db24..5ffd1d9 100644
--- a/drivers/vfio/pci/vfio_pci_rdwr.c
+++ b/drivers/vfio/pci/vfio_pci_rdwr.c
@@ -124,11 +124,14 @@ ssize_t vfio_pci_bar_rw(struct vfio_pci_device *vdev, char __user *buf,
void __iomem *io;
ssize_t done;

- if (!pci_resource_start(pdev, bar))
+ if (pci_resource_start(pdev, bar))
+ end = pci_resource_len(pdev, bar);
+ else if (bar == PCI_ROM_RESOURCE &&
+ pdev->resource[bar].flags & IORESOURCE_ROM_SHADOW)
+ end = 0x20000;
+ else
return -EINVAL;

- end = pci_resource_len(pdev, bar);
-
if (pos >= end)
return -EINVAL;