drm/i915/gvt: Add support for PCIe extended configuration space

IGD is PCIe device and has extended configuration space. Checking
the binary dump, we can see we have Caps located out of PCI compatible
Configuration Space range.

0x000: 86 80 12 19 17 04 10 00 06 00 00 03 00 00 00 00
0x010: 04 00 00 10 08 00 00 00 0c 00 00 00 08 00 00 00
0x020: 00 00 00 00 00 00 00 00 00 00 00 00 28 10 b9 06
0x030: 00 f8 ff ff 40 00 00 00 00 00 00 00 0b 01 00 00
0x040: 09 70 0c 01 71 26 01 62 c8 00 04 84 00 00 00 00
0x050: c1 00 00 00 39 00 00 00 00 00 00 00 01 00 00 a2
0x060: 00 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00
0x070: 10 ac 92 00 00 80 00 10 00 00 00 00 00 00 00 00
0x080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x090: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0a0: 00 00 00 00 00 00 00 00 00 00 00 00 05 d0 01 00
0x0b0: 18 00 e0 fe 00 00 00 00 00 00 00 00 00 00 00 00
0x0c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0d0: 01 00 22 00 00 80 00 00 00 00 00 00 00 00 00 00
0x0e0: 00 00 00 00 00 00 00 00 00 80 00 00 00 00 00 00
0x0f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x100: 1b 00 01 20 02 14 00 00 00 00 00 00 00 00 00 00
...

Currently, we only emulate the PCI compatible Configuration Space.
This is okay if we attach vGPU to PCI bus. But when we attach to
a PCI Express bus (when Qemu emulates a Intel Q35 chipset which has
PCIe slot), it will not work. Extended Configuration Space is required
for a PCIe device.

This patch extended the virtual configuration space from 256 bytes
to 4KB bytes. So we are to be a *real* PCIe device. And for the
Extended CapList we keep same to physical GPU.

Cc: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Changbin Du <changbin.du@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

drivers/gpu/drm/i915/gvt/cfg_space.c

@@ -101,7 +101,7 @@ int intel_vgpu_emulate_cfg_read(struct intel_vgpu *vgpu, unsigned int offset,
 	if (WARN_ON(bytes > 4))
 		return -EINVAL;
 
-	if (WARN_ON(offset + bytes > INTEL_GVT_MAX_CFG_SPACE_SZ))
+	if (WARN_ON(offset + bytes > vgpu->gvt->device_info.cfg_space_size))
 		return -EINVAL;
 
 	memcpy(p_data, vgpu_cfg_space(vgpu) + offset, bytes);
@@ -289,7 +289,7 @@ int intel_vgpu_emulate_cfg_write(struct intel_vgpu *vgpu, unsigned int offset,
 	if (WARN_ON(bytes > 4))
 		return -EINVAL;
 
-	if (WARN_ON(offset + bytes > INTEL_GVT_MAX_CFG_SPACE_SZ))
+	if (WARN_ON(offset + bytes > vgpu->gvt->device_info.cfg_space_size))
 		return -EINVAL;
 
 	/* First check if it's PCI_COMMAND */

drivers/gpu/drm/i915/gvt/gvt.c

@@ -111,7 +111,7 @@ static void init_device_info(struct intel_gvt *gvt)
 	if (IS_BROADWELL(gvt->dev_priv) || IS_SKYLAKE(gvt->dev_priv)
 		|| IS_KABYLAKE(gvt->dev_priv)) {
 		info->max_support_vgpus = 8;
-		info->cfg_space_size = 256;
+		info->cfg_space_size = PCI_CFG_SPACE_EXP_SIZE;
 		info->mmio_size = 2 * 1024 * 1024;
 		info->mmio_bar = 0;
 		info->gtt_start_offset = 8 * 1024 * 1024;

drivers/gpu/drm/i915/gvt/gvt.h

@@ -100,7 +100,6 @@ struct intel_vgpu_mmio {
 	bool disable_warn_untrack;
 };
 
-#define INTEL_GVT_MAX_CFG_SPACE_SZ 256
 #define INTEL_GVT_MAX_BAR_NUM 4
 
 struct intel_vgpu_pci_bar {
@@ -109,7 +108,7 @@ struct intel_vgpu_pci_bar {
 };
 
 struct intel_vgpu_cfg_space {
-	unsigned char virtual_cfg_space[INTEL_GVT_MAX_CFG_SPACE_SZ];
+	unsigned char virtual_cfg_space[PCI_CFG_SPACE_EXP_SIZE];
 	struct intel_vgpu_pci_bar bar[INTEL_GVT_MAX_BAR_NUM];
 };
 

drivers/gpu/drm/i915/gvt/kvmgt.c

@@ -978,7 +978,7 @@ static long intel_vgpu_ioctl(struct mdev_device *mdev, unsigned int cmd,
 		switch (info.index) {
 		case VFIO_PCI_CONFIG_REGION_INDEX:
 			info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
-			info.size = INTEL_GVT_MAX_CFG_SPACE_SZ;
+			info.size = vgpu->gvt->device_info.cfg_space_size;
 			info.flags = VFIO_REGION_INFO_FLAG_READ |
 				     VFIO_REGION_INFO_FLAG_WRITE;
 			break;