From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> commit 8195400f7ea95399f721ad21f4d663a62c65036f upstream. 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 <sf@xxxxxxxxxxx> Suggested-by: Stefan Fritsch <sf@xxxxxxxxxxx> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Cc: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx> Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx> Cc: Stefan Fritsch <sf@xxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Tested-by: Stefan Fritsch <sf@xxxxxxxxxxx> Reviewed-by: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20201019101523.4145-1-chris@xxxxxxxxxxxxxxxxxx (cherry picked from commit f566fdcd6cc49a9d5b5d782f56e3e7cb243f01b8) Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/i915/i915_drv.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -33,6 +33,8 @@ #include <uapi/drm/i915_drm.h> #include <uapi/drm/drm_fourcc.h> +#include <asm/hypervisor.h> + #include <linux/io-mapping.h> #include <linux/i2c.h> #include <linux/i2c-algo-bit.h> @@ -2197,7 +2199,9 @@ 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)
