[Intel-gfx] [PATCH v1] vfio/pci: Add support for opregion v2.0+

[Fred Gao]

When VBT data exceeds 6KB size and cannot be within mailbox #4 starting
from opregion v2.0+, Extended VBT region, next to opregion, is used to
hold the VBT data, so the total size will be opregion size plus
extended VBT region size.

For opregion 2.1+: since rvda is relative offset from opregion base,
rvda as extended VBT start offset should be same as opregion size.

For opregion 2.0: the only difference between opregion 2.0 and 2.1 is
rvda addressing mode besides the version. since rvda is physical host
VBT address and cannot be directly used in guest, it is faked into
opregion 2.1's relative offset.

Cc: Zhenyu Wang <zhenyuw at linux.intel.com>
Signed-off-by: Swee Yee Fonn <swee.yee.fonn at intel.com>
Signed-off-by: Fred Gao <fred.gao at intel.com>
---
 drivers/vfio/pci/vfio_pci_igd.c | 44 +++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/drivers/vfio/pci/vfio_pci_igd.c b/drivers/vfio/pci/vfio_pci_igd.c
index 53d97f459252..78919a289914 100644
--- a/drivers/vfio/pci/vfio_pci_igd.c
+++ b/drivers/vfio/pci/vfio_pci_igd.c
@@ -21,6 +21,17 @@
 #define OPREGION_SIZE		(8 * 1024)
 #define OPREGION_PCI_ADDR	0xfc
 
+/*
+ * opregion 2.0: rvda is the physical VBT address.
+ *
+ * opregion 2.1+: rvda is unsigned, relative offset from
+ * opregion base, and should never point within opregion.
+ */
+#define OPREGION_RDVA		0x3ba
+#define OPREGION_RDVS		0x3c2
+#define OPREGION_VERSION	22
+
+
 static size_t vfio_pci_igd_rw(struct vfio_pci_device *vdev, char __user *buf,
 			      size_t count, loff_t *ppos, bool iswrite)
 {
@@ -58,6 +69,7 @@ static int vfio_pci_igd_opregion_init(struct vfio_pci_device *vdev)
 	u32 addr, size;
 	void *base;
 	int ret;
+	u16 version;
 
 	ret = pci_read_config_dword(vdev->pdev, OPREGION_PCI_ADDR, &addr);
 	if (ret)
@@ -83,6 +95,38 @@ static int vfio_pci_igd_opregion_init(struct vfio_pci_device *vdev)
 
 	size *= 1024; /* In KB */
 
+	/* Support opregion v2.0+ */
+	version = le16_to_cpu(*(__le16 *)(base + OPREGION_VERSION));
+	if (version >= 0x0200) {
+		u64 rvda;
+		u32 rvds;
+
+		rvda = le64_to_cpu(*(__le64 *)(base + OPREGION_RDVA));
+		rvds = le32_to_cpu(*(__le32 *)(base + OPREGION_RDVS));
+		if (rvda && rvds) {
+			u32 offset;
+
+			if (version == 0x0200)
+				offset = (rvda - (u64)addr);
+			else
+				offset = rvda;
+
+			pci_WARN(vdev->pdev, offset != size,
+				"Extended VBT does not follow opregion !\n"
+				"opregion version 0x%x:offset 0x%x\n", version, offset);
+
+			if (version == 0x0200) {
+				/* opregion version v2.0 faked to v2.1 */
+				*(__le16 *)(base + OPREGION_VERSION) =
+					cpu_to_le16(0x0201);
+				/* rvda faked to relative offset */
+				(*(__le64 *)(base + OPREGION_RDVA)) =
+					cpu_to_le64((rvda - (u64)addr));
+			}
+			size = offset + rvds;
+		}
+	}
+
 	if (size != OPREGION_SIZE) {
 		memunmap(base);
 		base = memremap(addr, size, MEMREMAP_WB);
-- 
2.24.1.1.gb6d4d82bd5