Re: [RFC PATCH v4 5/7] vfio-pci: Allow to mmap sub-page MMIO BARs if the mmio page is exclusive
From: Alex Williamson <hidden>
Date: 2016-03-16 16:30:44
Also in:
kvm, linux-pci, lkml
On Mon, 7 Mar 2016 15:48:36 +0800 Yongji Xie [off-list ref] wrote:
quoted hunk ↗ jump to hunk
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 can make sure these BARs' mmio page will not be shared with other BARs. Signed-off-by: Yongji Xie <redacted> --- 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 1ce1d36..49d7a69 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c@@ -589,7 +589,8 @@ 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 && !pci_resources_share_page(pdev, + info.index)) {
this would be a preferable line wrap:
IORESOURCE_MEM &&
!pci_resources_share_page(pdev, info.index)) {
quoted hunk ↗ jump to hunk
info.flags |= VFIO_REGION_INFO_FLAG_MMAP; if (info.index == vdev->msix_bar) { ret = msix_sparse_mmap_cap(vdev, &caps);@@ -1016,6 +1017,10 @@ static int vfio_pci_mmap(void *device_data, struct vm_area_struct *vma) return -EINVAL; phys_len = pci_resource_len(pdev, index); + + if (!pci_resources_share_page(pdev, index)) + 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);