linux-kernel - [PATCH 4.9 10/60] drm/i915: Fix GVT-g PVINFO version compatibility check

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Date:   Mon, 19 Jun 2017 23:17:04 +0800
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
        Chuanxiao Dong <chuanxiao.dong@...el.com>,
        Zhenyu Wang <zhenyuw@...ux.intel.com>,
        Jani Nikula <jani.nikula@...el.com>
Subject: [PATCH 4.9 10/60] drm/i915: Fix GVT-g PVINFO version compatibility check

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Zhenyu Wang <zhenyuw@...ux.intel.com>

commit c380f681245d7ae57f17d9ebbbe8f8f1557ee1fb upstream.

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.

v2:
- drop unneeded version macro
- use only major version for sanity check

v3:
- fix up PVInfo value with kernel type
- one indent fix

Reviewed-by: Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>
Cc: Chuanxiao Dong <chuanxiao.dong@...el.com>
Cc: Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@...ux.intel.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170609074805.5101-1-zhenyuw@linux.intel.com
(cherry picked from commit 0c8792d00d38de85b6ceb1dd67d3ee009d7c8e42)
Signed-off-by: Jani Nikula <jani.nikula@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/gpu/drm/i915/i915_pvinfo.h |    8 ++------
 drivers/gpu/drm/i915/i915_vgpu.c   |   10 ++++------
 2 files changed, 6 insertions(+), 12 deletions(-)

--- a/drivers/gpu/drm/i915/i915_pvinfo.h
+++ b/drivers/gpu/drm/i915/i915_pvinfo.h
@@ -36,10 +36,6 @@
 #define VGT_VERSION_MAJOR 1
 #define VGT_VERSION_MINOR 0
 
-#define INTEL_VGT_IF_VERSION_ENCODE(major, minor) ((major) << 16 | (minor))
-#define INTEL_VGT_IF_VERSION \
-	INTEL_VGT_IF_VERSION_ENCODE(VGT_VERSION_MAJOR, VGT_VERSION_MINOR)
-
 /*
  * notifications from guest to vgpu device model
  */
@@ -55,8 +51,8 @@ enum vgt_g2v_type {
 
 struct vgt_if {
 	u64 magic;		/* VGT_MAGIC */
-	uint16_t version_major;
-	uint16_t version_minor;
+	u16 version_major;
+	u16 version_minor;
 	u32 vgt_id;		/* ID of vGT instance */
 	u32 rsv1[12];		/* pad to offset 0x40 */
 	/*
--- a/drivers/gpu/drm/i915/i915_vgpu.c
+++ b/drivers/gpu/drm/i915/i915_vgpu.c
@@ -60,8 +60,8 @@
  */
 void i915_check_vgpu(struct drm_i915_private *dev_priv)
 {
-	uint64_t magic;
-	uint32_t version;
+	u64 magic;
+	u16 version_major;
 
 	BUILD_BUG_ON(sizeof(struct vgt_if) != VGT_PVINFO_SIZE);
 
@@ -69,10 +69,8 @@ void i915_check_vgpu(struct drm_i915_pri
 	if (magic != VGT_MAGIC)
 		return;
 
-	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) {
+	version_major = __raw_i915_read16(dev_priv, vgtif_reg(version_major));
+	if (version_major < VGT_VERSION_MAJOR) {
 		DRM_INFO("VGT interface version mismatch!\n");
 		return;
 	}