drm/i915: Use per device iommu check

With both integrated and discrete Intel GPUs in a system, the current
global check of intel_iommu_gfx_mapped, as done from intel_vtd_active()
may not be completely accurate.

In this patch we add i915 parameter to intel_vtd_active() in order to
prepare it for multiple GPUs and we also change the check away from Intel
specific intel_iommu_gfx_mapped (global exported by the Intel IOMMU
driver) to probing the presence of IOMMU on a specific device using
device_iommu_mapped().

This will return true both for IOMMU pass-through and address translation
modes which matches the current behaviour. If in the future we wanted to
distinguish between these two modes we could either use
iommu_get_domain_for_dev() and check for __IOMMU_DOMAIN_PAGING bit
indicating address translation, or ask for a new API to be exported from
the IOMMU core code.

v2:
  * Check for dmar translation specifically, not just iommu domain. (Baolu)

v3:
 * Go back to plain "any domain" check for now, rewrite commit message.

v4:
 * Use device_iommu_mapped. (Robin, Baolu)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211126141424.493753-1-tvrtko.ursulin@linux.intel.com

drivers/gpu/drm/i915/display/intel_bw.c

@@ -490,7 +490,7 @@ static unsigned int intel_bw_data_rate(struct drm_i915_private *dev_priv,
 	for_each_pipe(dev_priv, pipe)
 		data_rate += bw_state->data_rate[pipe];
 
-	if (DISPLAY_VER(dev_priv) >= 13 && intel_vtd_active())
+	if (DISPLAY_VER(dev_priv) >= 13 && intel_vtd_active(dev_priv))
 		data_rate = data_rate * 105 / 100;
 
 	return data_rate;

drivers/gpu/drm/i915/display/intel_display.c

@@ -1919,7 +1919,7 @@ static bool needs_async_flip_vtd_wa(const struct intel_crtc_state *crtc_state)
 {
 	struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
 
-	return crtc_state->uapi.async_flip && intel_vtd_active() &&
+	return crtc_state->uapi.async_flip && intel_vtd_active(i915) &&
 		(DISPLAY_VER(i915) == 9 || IS_BROADWELL(i915) || IS_HASWELL(i915));
 }
 

drivers/gpu/drm/i915/display/intel_fbc.c

@@ -1539,7 +1539,7 @@ static int intel_sanitize_fbc_option(struct drm_i915_private *dev_priv)
 static bool need_fbc_vtd_wa(struct drm_i915_private *dev_priv)
 {
 	/* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl,bxt */
-	if (intel_vtd_active() &&
+	if (intel_vtd_active(dev_priv) &&
 	    (IS_SKYLAKE(dev_priv) || IS_BROXTON(dev_priv))) {
 		drm_info(&dev_priv->drm,
 			 "Disabling framebuffer compression (FBC) to prevent screen flicker with VT-d enabled\n");

drivers/gpu/drm/i915/gem/i915_gem_stolen.c

@@ -399,7 +399,7 @@ static int i915_gem_init_stolen(struct intel_memory_region *mem)
 		return 0;
 	}
 
-	if (intel_vtd_active() && GRAPHICS_VER(i915) < 8) {
+	if (intel_vtd_active(i915) && GRAPHICS_VER(i915) < 8) {
 		drm_notice(&i915->drm,
 			   "%s, disabling use of stolen memory\n",
 			   "DMAR active");

drivers/gpu/drm/i915/gem/i915_gemfs.c

@@ -32,7 +32,7 @@ int i915_gemfs_init(struct drm_i915_private *i915)
 	 */
 
 	opts = NULL;
-	if (intel_vtd_active()) {
+	if (intel_vtd_active(i915)) {
 		if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
 			opts = huge_opt;
 			drm_info(&i915->drm,

drivers/gpu/drm/i915/gt/intel_ggtt.c

@@ -104,7 +104,7 @@ static bool needs_idle_maps(struct drm_i915_private *i915)
 	 * Query intel_iommu to see if we need the workaround. Presumably that
 	 * was loaded first.
 	 */
-	if (!intel_vtd_active())
+	if (!intel_vtd_active(i915))
 		return false;
 
 	if (GRAPHICS_VER(i915) == 5 && IS_MOBILE(i915))
@@ -1216,7 +1216,7 @@ int i915_ggtt_probe_hw(struct drm_i915_private *i915)
 	if (ret)
 		return ret;
 
-	if (intel_vtd_active())
+	if (intel_vtd_active(i915))
 		drm_info(&i915->drm, "VT-d active for gfx access\n");
 
 	return 0;

drivers/gpu/drm/i915/i915_debugfs.c

@@ -65,6 +65,7 @@ static int i915_capabilities(struct seq_file *m, void *data)
 
 	intel_device_info_print_static(INTEL_INFO(i915), &p);
 	intel_device_info_print_runtime(RUNTIME_INFO(i915), &p);
+	i915_print_iommu_status(i915, &p);
 	intel_gt_info_print(&i915->gt.info, &p);
 	intel_driver_caps_print(&i915->caps, &p);
 

drivers/gpu/drm/i915/i915_drv.c

@@ -738,6 +738,12 @@ static void i915_driver_unregister(struct drm_i915_private *dev_priv)
 	i915_gem_driver_unregister(dev_priv);
 }
 
+void
+i915_print_iommu_status(struct drm_i915_private *i915, struct drm_printer *p)
+{
+	drm_printf(p, "iommu: %s\n", enableddisabled(intel_vtd_active(i915)));
+}
+
 static void i915_welcome_messages(struct drm_i915_private *dev_priv)
 {
 	if (drm_debug_enabled(DRM_UT_DRIVER)) {
@@ -753,6 +759,7 @@ static void i915_welcome_messages(struct drm_i915_private *dev_priv)
 
 		intel_device_info_print_static(INTEL_INFO(dev_priv), &p);
 		intel_device_info_print_runtime(RUNTIME_INFO(dev_priv), &p);
+		i915_print_iommu_status(dev_priv, &p);
 		intel_gt_info_print(&dev_priv->gt.info, &p);
 	}
 

drivers/gpu/drm/i915/i915_drv.h

@@ -1764,26 +1764,27 @@ static inline bool run_as_guest(void)
 #define HAS_D12_PLANE_MINIMIZATION(dev_priv) (IS_ROCKETLAKE(dev_priv) || \
 					      IS_ALDERLAKE_S(dev_priv))
 
-static inline bool intel_vtd_active(void)
+static inline bool intel_vtd_active(struct drm_i915_private *i915)
 {
-#ifdef CONFIG_INTEL_IOMMU
-	if (intel_iommu_gfx_mapped)
+	if (device_iommu_mapped(i915->drm.dev))
 		return true;
-#endif
 
 	/* Running as a guest, we assume the host is enforcing VT'd */
 	return run_as_guest();
 }
 
+void
+i915_print_iommu_status(struct drm_i915_private *i915, struct drm_printer *p);
+
 static inline bool intel_scanout_needs_vtd_wa(struct drm_i915_private *dev_priv)
 {
-	return GRAPHICS_VER(dev_priv) >= 6 && intel_vtd_active();
+	return GRAPHICS_VER(dev_priv) >= 6 && intel_vtd_active(dev_priv);
 }
 
 static inline bool
 intel_ggtt_update_needs_vtd_wa(struct drm_i915_private *i915)
 {
-	return IS_BROXTON(i915) && intel_vtd_active();
+	return IS_BROXTON(i915) && intel_vtd_active(i915);
 }
 
 static inline bool

drivers/gpu/drm/i915/i915_gpu_error.c

@@ -1754,10 +1754,7 @@ static void capture_gen(struct i915_gpu_coredump *error)
 	error->wakelock = atomic_read(&i915->runtime_pm.wakeref_count);
 	error->suspended = i915->runtime_pm.suspended;
 
-	error->iommu = -1;
-#ifdef CONFIG_INTEL_IOMMU
-	error->iommu = intel_iommu_gfx_mapped;
-#endif
+	error->iommu = intel_vtd_active(i915);
 	error->reset_count = i915_reset_count(&i915->gpu_error);
 	error->suspend_count = i915->suspend_count;
 

drivers/gpu/drm/i915/intel_device_info.c

@@ -83,17 +83,6 @@ const char *intel_platform_name(enum intel_platform platform)
 	return platform_names[platform];
 }
 
-static const char *iommu_name(void)
-{
-	const char *msg = "n/a";
-
-#ifdef CONFIG_INTEL_IOMMU
-	msg = enableddisabled(intel_iommu_gfx_mapped);
-#endif
-
-	return msg;
-}
-
 void intel_device_info_print_static(const struct intel_device_info *info,
 				    struct drm_printer *p)
 {
@@ -114,7 +103,6 @@ void intel_device_info_print_static(const struct intel_device_info *info,
 		drm_printf(p, "display version: %u\n", info->display.ver);
 
 	drm_printf(p, "gt: %d\n", info->gt);
-	drm_printf(p, "iommu: %s\n", iommu_name());
 	drm_printf(p, "memory-regions: %x\n", info->memory_regions);
 	drm_printf(p, "page-sizes: %x\n", info->page_sizes);
 	drm_printf(p, "platform: %s\n", intel_platform_name(info->platform));
@@ -374,7 +362,7 @@ void intel_device_info_runtime_init(struct drm_i915_private *dev_priv)
 			info->display.has_dsc = 0;
 	}
 
-	if (GRAPHICS_VER(dev_priv) == 6 && intel_vtd_active()) {
+	if (GRAPHICS_VER(dev_priv) == 6 && intel_vtd_active(dev_priv)) {
 		drm_info(&dev_priv->drm,
 			 "Disabling ppGTT for VT-d support\n");
 		info->ppgtt_type = INTEL_PPGTT_NONE;

drivers/gpu/drm/i915/intel_pm.c

@@ -97,7 +97,7 @@ static void gen9_init_clock_gating(struct drm_i915_private *dev_priv)
 		 * "Plane N strech max must be programmed to 11b (x1)
 		 *  when Async flips are enabled on that plane."
 		 */
-		if (!IS_GEMINILAKE(dev_priv) && intel_vtd_active())
+		if (!IS_GEMINILAKE(dev_priv) && intel_vtd_active(dev_priv))
 			intel_uncore_rmw(&dev_priv->uncore, CHICKEN_PIPESL_1(pipe),
 					 SKL_PLANE1_STRETCH_MAX_MASK, SKL_PLANE1_STRETCH_MAX_X1);
 	}