Re: [PATCH 1/9] drm/xe/rtp: Add RING_FORCE_TO_NONPRIV_DENY to OA whitelists

["Dixit, Ashutosh" <ashutosh.dixit@intel.com>]

On Thu, 21 May 2026 16:14:50 -0700, Umesh Nerlige Ramappa wrote:
>
> On Mon, May 18, 2026 at 04:47:08PM -0700, Ashutosh Dixit wrote:
> > Unconditionally whitelisting OA registers is a security violation. Set
> > RING_FORCE_TO_NONPRIV_DENY bit in OA nonpriv slots, so that OA registers
> > don't get whitelisted by default after probe/reset/restart.
> >
> > Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
> > ---
> > drivers/gpu/drm/xe/xe_reg_whitelist.c | 7 ++++---
> > 1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/xe/xe_reg_whitelist.c b/drivers/gpu/drm/xe/xe_reg_whitelist.c
> > index fb65940848d7a..d6a5d499373bc 100644
> > --- a/drivers/gpu/drm/xe/xe_reg_whitelist.c
> > +++ b/drivers/gpu/drm/xe/xe_reg_whitelist.c
> > @@ -105,9 +105,10 @@ static const struct xe_rtp_entry_sr register_whitelist[] = {
> >	},
> >
> > #define WHITELIST_OA_MMIO_TRG(trg, status, head) \
> > -	WHITELIST(trg, RING_FORCE_TO_NONPRIV_ACCESS_RW), \
> > -	WHITELIST(status, RING_FORCE_TO_NONPRIV_ACCESS_RD), \
> > -	WHITELIST(head, RING_FORCE_TO_NONPRIV_ACCESS_RD | RING_FORCE_TO_NONPRIV_RANGE_4)
> > +	WHITELIST(trg, RING_FORCE_TO_NONPRIV_ACCESS_RW | RING_FORCE_TO_NONPRIV_DENY), \
> > +	WHITELIST(status, RING_FORCE_TO_NONPRIV_ACCESS_RD | RING_FORCE_TO_NONPRIV_DENY), \
> > +	WHITELIST(head, RING_FORCE_TO_NONPRIV_ACCESS_RD | RING_FORCE_TO_NONPRIV_RANGE_4 | \
> > +		  RING_FORCE_TO_NONPRIV_DENY)
>
> status and head should be clubbed into one slot, starting with status and
> RANGE_4. Maybe that can be a patch before this one.

No, e.g. for OAG, status is 0xdafc which is not a multiple of 16, which is
a requirement for RANGE_4.

Also, about RANGE_4 above, there were different suggestions, e.g. tail and
oabuffer should be different slots, rather than grouping in a single
RANGE_4 above. To avoid any such controversy, I decided to focus this
series only on removing unconditional whitelisting for OA registers. Any
other changes, such as removing or retaining RANGE_4, we can do after this
series is reviewed/merged.

Thanks.
--
Ashutosh

> > #define WHITELIST_OAG_MMIO_TRG \
> >	WHITELIST_OA_MMIO_TRG(OAG_MMIOTRIGGER, OAG_OASTATUS, OAG_OAHEADPTR)
> > --
> > 2.54.0
> >