drivers/vfio/pci/vfio_pci.c | 87 ++++++++++++++++++++++++++++++++---
drivers/vfio/pci/vfio_pci_private.h | 8 ++++
2 files changed, 89 insertions(+), 6 deletions(-)
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 188b1ff..3cca2a7 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -110,6 +110,73 @@ static inline bool vfio_pci_is_vga(struct pci_dev *pdev)
return (pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA;
}
+static void vfio_pci_probe_mmaps(struct vfio_pci_device *vdev)
+{
+ struct resource *res;
+ int bar;
+ struct vfio_pci_dummy_resource *dummy_res;
+
+ INIT_LIST_HEAD(&vdev->dummy_resources_list);
+
+ for (bar = PCI_STD_RESOURCES; bar <= PCI_STD_RESOURCE_END; bar++) {
+ res = vdev->pdev->resource + bar;
+
+ if (!IS_ENABLED(CONFIG_VFIO_PCI_MMAP))
+ goto no_mmap;
+
+ if (!(res->flags & IORESOURCE_MEM))
+ goto no_mmap;
+
+ /*
+ * The PCI core shouldn't set up a resource with a
+ * type but zero size. But there may be bugs that
+ * cause us to do that.
+ */
+ if (!resource_size(res))
+ goto no_mmap;
+
+ if (resource_size(res) >= PAGE_SIZE) {
+ vdev->bar_mmap_supported[bar] = true;
+ continue;
+ }
+
+ if (!(res->start & ~PAGE_MASK)) {
+ /*
+ * Add a dummy resource to reserve the remainder
+ * of the exclusive page in case that hot-add
+ * device's bar is assigned into it.
+ */
+ dummy_res = kzalloc(sizeof(*dummy_res), GFP_KERNEL);
+ if (dummy_res == NULL)
+ goto no_mmap;
+
+ dummy_res->resource.start = res->end + 1;
+ dummy_res->resource.end = res->start + PAGE_SIZE - 1;
+ dummy_res->resource.flags = res->flags;
+ if (request_resource(res->parent,
+ &dummy_res->resource)) {
+ kfree(dummy_res);
+ goto no_mmap;
+ }
+ dummy_res->index = bar;
+ list_add(&dummy_res->res_next,
+ &vdev->dummy_resources_list);
+ vdev->bar_mmap_supported[bar] = true;
+ continue;
+ }
+ /*
+ * Here we don't handle the case when the BAR is not page
+ * aligned because we can't expect the BAR will be
+ * assigned into the same location in a page in guest
+ * when we passthrough the BAR. And it's hard to access
+ * this BAR in userspace because we have no way to get
+ * the BAR's location in a page.
+ */
+no_mmap:
+ vdev->bar_mmap_supported[bar] = false;
+ }
+}
+
static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev);
static void vfio_pci_disable(struct vfio_pci_device *vdev);
@@ -218,12 +285,15 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev)
}
}
+ vfio_pci_probe_mmaps(vdev);
+
return 0;
}
static void vfio_pci_disable(struct vfio_pci_device *vdev)
{
struct pci_dev *pdev = vdev->pdev;
+ struct vfio_pci_dummy_resource *dummy_res, *tmp;
int i, bar;
/* Stop the device from further DMA */
@@ -252,6 +322,13 @@ static void vfio_pci_disable(struct vfio_pci_device *vdev)
vdev->barmap[bar] = NULL;
}
+ list_for_each_entry_safe(dummy_res, tmp,
+ &vdev->dummy_resources_list, res_next) {
+ list_del(&dummy_res->res_next);
+ release_resource(&dummy_res->resource);
+ kfree(dummy_res);
+ }
+
vdev->needs_reset = true;
/*
@@ -623,9 +700,7 @@ static long vfio_pci_ioctl(void *device_data,
info.flags = VFIO_REGION_INFO_FLAG_READ |
VFIO_REGION_INFO_FLAG_WRITE;
- if (IS_ENABLED(CONFIG_VFIO_PCI_MMAP) &&
- pci_resource_flags(pdev, info.index) &
- IORESOURCE_MEM && info.size >= PAGE_SIZE) {
+ if (vdev->bar_mmap_supported[info.index]) {
info.flags |= VFIO_REGION_INFO_FLAG_MMAP;
if (info.index == vdev->msix_bar) {
ret = msix_sparse_mmap_cap(vdev, &caps);
@@ -1049,16 +1124,16 @@ static int vfio_pci_mmap(void *device_data, struct vm_area_struct *vma)
return -EINVAL;
if (index >= VFIO_PCI_ROM_REGION_INDEX)
return -EINVAL;
- if (!(pci_resource_flags(pdev, index) & IORESOURCE_MEM))
+ if (!vdev->bar_mmap_supported[index])
return -EINVAL;
- phys_len = pci_resource_len(pdev, index);
+ phys_len = PAGE_ALIGN(pci_resource_len(pdev, index));
req_len = vma->vm_end - vma->vm_start;
pgoff = vma->vm_pgoff &
((1U << (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT)) - 1);
req_start = pgoff << PAGE_SHIFT;
- if (phys_len < PAGE_SIZE || req_start + req_len > phys_len)
+ if (req_start + req_len > phys_len)
return -EINVAL;
if (index == vdev->msix_bar) {
diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h
index 016c14a..2128de8 100644
--- a/drivers/vfio/pci/vfio_pci_private.h
+++ b/drivers/vfio/pci/vfio_pci_private.h
@@ -57,9 +57,16 @@ struct vfio_pci_region {
u32 flags;
};
+struct vfio_pci_dummy_resource {
+ struct resource resource;
+ int index;
+ struct list_head res_next;
+};
+
struct vfio_pci_device {
struct pci_dev *pdev;
void __iomem *barmap[PCI_STD_RESOURCE_END + 1];
+ bool bar_mmap_supported[PCI_STD_RESOURCE_END + 1];
u8 *pci_config_map;
u8 *vconfig;
struct perm_bits *msi_perm;
@@ -88,6 +95,7 @@ struct vfio_pci_device {
int refcnt;
struct eventfd_ctx *err_trigger;
struct eventfd_ctx *req_trigger;
+ struct list_head dummy_resources_list;
};
#define is_intx(vdev) (vdev->irq_type == VFIO_PCI_INTX_IRQ_INDEX)
