On 2020.10.19 11:15:23 +0100, Chris Wilson wrote: > 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 causing 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 > --- > 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 1a5729932c81..bcd8650603d8 100644 > --- 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> > @@ -1760,7 +1762,9 @@ 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) > -- Reviewed-by: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx> -- $gpg --keyserver wwwkeys.pgp.net --recv-keys 4D781827
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