[PATCH] drm/i915: Fix GVT-g PVINFO version compatibility check

[Zhenyu Wang]

Current it's strictly checked if PVINFO version matches 1.0
for GVT-g i915 guest which doesn't help for compatibility at
all and forces GVT-g host can't extend PVINFO easily with version
bump for real compatibility check.

This fixes that to check minimal required PVINFO version instead
and currently minimal 1.0 is required.

Cc: Chuanxiao Dong <chuanxiao.dong at intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: stable at vger.kernel.org # 4.10+
Signed-off-by: Zhenyu Wang <zhenyuw at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_pvinfo.h | 3 ++-
 drivers/gpu/drm/i915/i915_vgpu.c   | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_pvinfo.h b/drivers/gpu/drm/i915/i915_pvinfo.h
index c0cb2974caac..96434707857e 100644
--- a/drivers/gpu/drm/i915/i915_pvinfo.h
+++ b/drivers/gpu/drm/i915/i915_pvinfo.h
@@ -37,7 +37,8 @@
 #define VGT_VERSION_MINOR 0
 
 #define INTEL_VGT_IF_VERSION_ENCODE(major, minor) ((major) << 16 | (minor))
-#define INTEL_VGT_IF_VERSION \
+/* minimal required PVINFO version */
+#define INTEL_VGT_IF_VERSION_REQUIRED \
 	INTEL_VGT_IF_VERSION_ENCODE(VGT_VERSION_MAJOR, VGT_VERSION_MINOR)
 
 /*
diff --git a/drivers/gpu/drm/i915/i915_vgpu.c b/drivers/gpu/drm/i915/i915_vgpu.c
index 4ab8a973b61f..5798572e6db3 100644
--- a/drivers/gpu/drm/i915/i915_vgpu.c
+++ b/drivers/gpu/drm/i915/i915_vgpu.c
@@ -72,7 +72,7 @@ void i915_check_vgpu(struct drm_i915_private *dev_priv)
 	version = INTEL_VGT_IF_VERSION_ENCODE(
 		__raw_i915_read16(dev_priv, vgtif_reg(version_major)),
 		__raw_i915_read16(dev_priv, vgtif_reg(version_minor)));
-	if (version != INTEL_VGT_IF_VERSION) {
+	if (version < INTEL_VGT_IF_VERSION_REQUIRED) {
 		DRM_INFO("VGT interface version mismatch!\n");
 		return;
 	}
-- 
2.11.0