[RFC PATCH v3 5/5] vfio-pci: Allow to mmap MSI-X table if host bridge supports filtering of MSIs

[Yongji Xie <xyjxie@linux.vnet.ibm.com>]

Current vfio-pci implementation disallows to mmap MSI-X
table in case that user get to touch this directly.

But we should allow to mmap these MSI-X tables if the PCI
host bridge supports filtering of MSIs.

Signed-off-by: Yongji Xie <xyjxie@linux.vnet.ibm.com>
---
 drivers/vfio/pci/vfio_pci.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 11fd0f0..4d68f6a 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -555,7 +555,8 @@ static long vfio_pci_ioctl(void *device_data,
 			    IORESOURCE_MEM && !pci_resources_share_page(pdev,
 			    info.index)) {
 				info.flags |= VFIO_REGION_INFO_FLAG_MMAP;
-				if (info.index == vdev->msix_bar) {
+				if (!pci_host_bridge_msi_filtered_enabled(pdev) &&
+				    info.index == vdev->msix_bar) {
 					ret = msix_sparse_mmap_cap(vdev, &caps);
 					if (ret)
 						return ret;
@@ -967,7 +968,8 @@ 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 (!pci_host_bridge_msi_filtered_enabled(pdev) &&
+	    index == vdev->msix_bar) {
 		/*
 		 * Disallow mmaps overlapping the MSI-X table; users don't
 		 * get to touch this directly.  We could find somewhere
-- 
1.7.9.5