[PATCH] drm/i915/gvt: Stop initializing pvinfo through reading mmio

[Zhang, Tina]

> -----Original Message-----
> From: Zhenyu Wang <zhenyuw at linux.intel.com>
> Sent: Tuesday, November 5, 2019 10:54 AM
> To: Zhang, Tina <tina.zhang at intel.com>
> Cc: intel-gvt-dev at lists.freedesktop.org
> Subject: Re: [PATCH] drm/i915/gvt: Stop initializing pvinfo through reading
> mmio
> 
> On 2019.11.04 13:31:48 +0800, Tina Zhang wrote:
> > The region of pvinfo is reserved for communication between a VMM and
> > the GPU driver executing on a virtual machine. HW doesn't have any
> > backing mmio store support for the pvinfo region, thus accessing to
> > this range through MMIO read/write from host side is forbidden which
> > is regarded as unclaimed register access.
> >
> > This patch leaves pvinfo range be initialized with zero.
> >
> > Signed-off-by: Tina Zhang <tina.zhang at intel.com>
> > ---
> >  drivers/gpu/drm/i915/gvt/handlers.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/gvt/handlers.c
> > b/drivers/gpu/drm/i915/gvt/handlers.c
> > index afd7f66bdc2d..bd12af349123 100644
> > --- a/drivers/gpu/drm/i915/gvt/handlers.c
> > +++ b/drivers/gpu/drm/i915/gvt/handlers.c
> > @@ -3420,6 +3420,10 @@ int intel_gvt_for_each_tracked_mmio(struct
> intel_gvt *gvt,
> >  	}
> >
> >  	for (i = 0; i < gvt->mmio.num_mmio_block; i++, block++) {
> > +		/* pvinfo data doesn't come from hw mmio */
> > +		if (i915_mmio_reg_offset(block->offset) ==
> VGT_PVINFO_PAGE)
> > +			continue;
> 
> Equal to remove PVINFO in mmio_block list? Could we just remove it there
> instead of this special case?
Commit 65f9f6feb wanted it to be kept in in mmio_block for performance consideration. Thanks.

BR,
Tina
> > +
> >  		for (j = 0; j < block->size; j += 4) {
> >  			ret = handler(gvt,
> >  				      i915_mmio_reg_offset(block->offset) + j,
> > --
> > 2.17.1
> >
> 
> --
> Open Source Technology Center, Intel ltd.
> 
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