Current vfio-pci implementation disallows to mmap
sub-page(size < PAGE_SIZE) MMIO BARs because these BARs' mmio
page may be shared with other BARs.
But we should allow to mmap these sub-page MMIO BARs if PCI
resource allocator enforces the alignment of all MMIO BARs
to be at least PAGE_SIZE.
Signed-off-by: Yongji Xie <xyj...@linux.vnet.ibm.com>
---
drivers/vfio/pci/vfio_pci.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 7e9f497..09b3805 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -552,7 +552,8 @@ static long vfio_pci_ioctl(void *device_data,
VFIO_REGION_INFO_FLAG_WRITE;
if (IS_ENABLED(CONFIG_VFIO_PCI_MMAP) &&
pci_resource_flags(pdev, info.index) &
- IORESOURCE_MEM && info.size >= PAGE_SIZE) {
+ IORESOURCE_MEM && (info.size >= PAGE_SIZE ||
+ pci_resource_page_aligned)) {
info.flags |= VFIO_REGION_INFO_FLAG_MMAP;
if (info.index == vdev->msix_bar) {
ret = msix_sparse_mmap_cap(vdev, &caps);
@@ -954,6 +955,10 @@ static int vfio_pci_mmap(void *device_data, struct
vm_area_struct *vma)
return -EINVAL;
phys_len = pci_resource_len(pdev, index);
+
+ if (pci_resource_page_aligned)
+ phys_len = PAGE_ALIGN(phys_len);
+
req_len = vma->vm_end - vma->vm_start;
pgoff = vma->vm_pgoff &
((1U << (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT)) - 1);
--
1.7.9.5
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