From f566fdcd6cc49a9d5b5d782f56e3e7cb243f01b8 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 19 Oct 2020 11:15:23 +0100 Subject: [PATCH] drm/i915: Force VT'd workarounds when running as a guest OS If i915.ko is being used as a passthrough device, it does not know if the host is using intel_iommu. Mixing the iommu and gfx causes a few issues (such as scanout overfetch) which we need to workaround inside the driver, so if we detect we are running under a hypervisor, also assume the device access is being virtualised. Reported-by: Stefan Fritsch Suggested-by: Stefan Fritsch Signed-off-by: Chris Wilson Cc: Zhenyu Wang Cc: Joonas Lahtinen Cc: Stefan Fritsch Cc: stable@vger.kernel.org Tested-by: Stefan Fritsch Reviewed-by: Zhenyu Wang Link: https://patchwork.freedesktop.org/patch/msgid/20201019101523.4145-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_drv.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 8033a389d712..938f3db26e4f 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -33,6 +33,8 @@ #include #include +#include + #include #include #include @@ -1761,7 +1763,9 @@ static inline bool intel_vtd_active(void) if (intel_iommu_gfx_mapped) return true; #endif - return false; + + /* Running as a guest, we assume the host is enforcing VT'd */ + return !hypervisor_is_type(X86_HYPER_NATIVE); } static inline bool intel_scanout_needs_vtd_wa(struct drm_i915_private *dev_priv) -- 2.20.1