[Intel-gfx] [PATCH v1] vfio/pci: Refine Intel IGD OpRegion support

[Fred Gao]

Bypass the IGD initialization for Intel's dgfx devices with own expansion
ROM and the host/LPC bridge config space are no longer accessed.

Cc: Zhenyu Wang <zhenyuw at linux.intel.com>
Cc: Xiong Zhang <xiong.y.zhang at intel.com>
Cc: Hang Yuan <hang.yuan at linux.intel.com>
Cc: Stuart Summers <stuart.summers at intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
Signed-off-by: Fred Gao <fred.gao at intel.com>
---
 drivers/vfio/pci/vfio_pci.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index f634c81998bb..0f4a34849836 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -28,6 +28,8 @@
 #include <linux/nospec.h>
 #include <linux/sched/mm.h>
 
+#include <drm/i915_pciids.h>
+
 #include "vfio_pci_private.h"
 
 #define DRIVER_VERSION  "0.2"
@@ -60,6 +62,12 @@ module_param(enable_sriov, bool, 0644);
 MODULE_PARM_DESC(enable_sriov, "Enable support for SR-IOV configuration.  Enabling SR-IOV on a PF typically requires support of the userspace PF driver, enabling VFs without such support may result in non-functional VFs or PF.");
 #endif
 
+/* Intel's dgfx is not IGD, so don't handle them the same way */
+static const struct pci_device_id intel_dgfx_pciids[] = {
+	INTEL_DG1_IDS(0),
+	{ }
+};
+
 static inline bool vfio_vga_disabled(void)
 {
 #ifdef CONFIG_VFIO_PCI_VGA
@@ -339,7 +347,8 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev)
 
 	if (vfio_pci_is_vga(pdev) &&
 	    pdev->vendor == PCI_VENDOR_ID_INTEL &&
-	    IS_ENABLED(CONFIG_VFIO_PCI_IGD)) {
+	    IS_ENABLED(CONFIG_VFIO_PCI_IGD) &&
+	    !pci_match_id(intel_dgfx_pciids, pdev)) {
 		ret = vfio_pci_igd_init(vdev);
 		if (ret) {
 			pci_warn(pdev, "Failed to setup Intel IGD regions\n");
-- 
2.24.1.1.gb6d4d82bd5