This patch tries to expose MSI-X tables to userspace if hardware
enables interrupt remapping. This capability can ensure that a
given PCI device can only shoot the MSIs assigned for it. That
means a userspace driver could never hurt other devices or system
by writing to the exposed MSI-X table directly.
Signed-off-by: Yongji Xie <xyjxie@xxxxxxxxxxxxxxxxxx>
---
drivers/vfio/pci/vfio_pci.c | 17 ++++++++++++++---
drivers/vfio/pci/vfio_pci_rdwr.c | 3 ++-
2 files changed, 16 insertions(+), 4 deletions(-)
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 188b1ff..6bae388 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -487,8 +487,12 @@ static int msix_sparse_mmap_cap(struct vfio_pci_device *vdev,
end = pci_resource_len(vdev->pdev, vdev->msix_bar);
- /* If MSI-X table is aligned to the start or end, only one area */
- if (((vdev->msix_offset & PAGE_MASK) == 0) ||
+ /*
+ * If MSI-X table is allowed to mmap because of the capability
+ * of IRQ remapping or aligned to the start or end, only one area
+ */
+ if ((vdev->pdev->bus->bus_flags & PCI_BUS_FLAGS_MSI_REMAP) ||
+ ((vdev->msix_offset & PAGE_MASK) == 0) ||
(PAGE_ALIGN(vdev->msix_offset + vdev->msix_size) >= end))
nr_areas = 1;
@@ -503,6 +507,12 @@ static int msix_sparse_mmap_cap(struct vfio_pci_device *vdev,
struct vfio_region_info_cap_sparse_mmap, header);
sparse->nr_areas = nr_areas;
+ if (vdev->pdev->bus->bus_flags & PCI_BUS_FLAGS_MSI_REMAP) {
+ sparse->areas[i].offset = 0;
+ sparse->areas[i].size = end;
+ return 0;
+ }
+
if (vdev->msix_offset & PAGE_MASK) {
sparse->areas[i].offset = 0;
sparse->areas[i].size = vdev->msix_offset & PAGE_MASK;
@@ -1061,7 +1071,8 @@ static int vfio_pci_mmap(void *device_data, struct vm_area_struct *vma)
if (phys_len < PAGE_SIZE || req_start + req_len > phys_len)
return -EINVAL;
- if (index == vdev->msix_bar) {
+ if (index == vdev->msix_bar &&
+ !(pdev->bus->bus_flags & PCI_BUS_FLAGS_MSI_REMAP)) {
/*
* Disallow mmaps overlapping the MSI-X table; users don't
* get to touch this directly. We could find somewhere
diff --git a/drivers/vfio/pci/vfio_pci_rdwr.c b/drivers/vfio/pci/vfio_pci_rdwr.c
index 5ffd1d9..dbf9cd0 100644
--- a/drivers/vfio/pci/vfio_pci_rdwr.c
+++ b/drivers/vfio/pci/vfio_pci_rdwr.c
@@ -164,7 +164,8 @@ ssize_t vfio_pci_bar_rw(struct vfio_pci_device *vdev, char __user *buf,
} else
io = vdev->barmap[bar];
- if (bar == vdev->msix_bar) {
+ if (bar == vdev->msix_bar &&
+ !(pdev->bus->bus_flags & PCI_BUS_FLAGS_MSI_REMAP)) {
x_start = vdev->msix_offset;
x_end = vdev->msix_offset + vdev->msix_size;
}
--
1.7.9.5
--
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