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|---|---|
| From | Yongji Xie <xyjxie@linux.vnet.ibm.com> |
| Newsgroups | linux.kernel |
| Subject | [RFC PATCH v3 2/5] vfio-pci: Allow to mmap sub-page MMIO BARs if the mmio page is exclusive |
| Date | Fri, 15 Jan 2016 08:10:02 +0100 |
| Message-ID | <qR6Ge-2DL-21@gated-at.bofh.it> (permalink) |
| References | <qR6Gd-2DL-7@gated-at.bofh.it> |
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| X-Original-Cc | bhelgaas@google.com, corbet@lwn.net, aik@ozlabs.ru, alex.williamson@redhat.com, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, warrier@linux.vnet.ibm.com, zhong@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, Yongji Xie <xyjxie@linux.vnet.ibm.com> |
| X-Original-Date | Fri, 15 Jan 2016 15:06:11 +0800 |
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| Xref | csiph.com linux.kernel:1309918 |
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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 can make sure these BARs' mmio page will
not be shared with other BARs.
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..11fd0f0 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 && !pci_resources_share_page(pdev,
+ info.index)) {
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_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);
--
1.7.9.5
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[RFC PATCH v3 2/5] vfio-pci: Allow to mmap sub-page MMIO BARs if the mmio page is exclusive Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-01-15 08:10 +0100
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