Messages in this thread Patch in this message | | | From | Yongji Xie <> | Subject | [RFC PATCH v2 2/3] vfio-pci: Allow to mmap sub-page MMIO BARs if all MMIO BARs are page aligned | Date | Thu, 31 Dec 2015 16:50:43 +0800 |
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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 <xyjxie@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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