[Intel-gfx] [topic/core-for-ci v2] iommu/vt-d: Check domain flags before setting snp bit in page-control

[Sripada, Radhakrishna]

> -----Original Message-----
> From: Rodrigo Vivi <rodrigo.vivi at kernel.org>
> Sent: Friday, August 25, 2023 10:24 AM
> To: Sripada, Radhakrishna <radhakrishna.sripada at intel.com>
> Cc: Jani Nikula <jani.nikula at linux.intel.com>; intel-gfx at lists.freedesktop.org;
> Raj, Ashok <ashok.raj at intel.com>
> Subject: Re: [Intel-gfx] [topic/core-for-ci v2] iommu/vt-d: Check domain flags
> before setting snp bit in page-control
> 
> On Fri, Aug 25, 2023 at 02:15:27PM +0000, Sripada, Radhakrishna wrote:
> > I was trying this as a solution for the Pipe fault errors. However, I still see
> > The pipe fault errors which do not occur all the time.
> 
> We should avoid overloading CI with tests. But if needed because we cannot
> reproduce locally but only on CI, please use the try-bot list instead of
> this one.
> 
> And in the very last case where this list needs to be used, please use
> another prefix like CI or HAX, but not the topic/core-for-ci, otherwise
> we will think you are already asking to get that merged there.

Sure will update that. This is a tricky bug that resurfaced after removing
Iommu=pt kernel command line. I already took down one CI resume system for
debug but the issue occurrence now seems to be intermittent and difficult to narrow down.

Anyways thank you Rodrigo will add the CI tag for later if try bot does not help.

Thanks,
Radhakrishna Sripada
> 
> >
> > Will update the explanation in my follow up patches.
> 
> >
> > Thanks,
> > Radhakrishna Sripada
> >
> > > -----Original Message-----
> > > From: Jani Nikula <jani.nikula at linux.intel.com>
> > > Sent: Thursday, August 24, 2023 11:54 PM
> > > To: Sripada, Radhakrishna <radhakrishna.sripada at intel.com>; intel-
> > > gfx at lists.freedesktop.org
> > > Cc: Raj, Ashok <ashok.raj at intel.com>
> > > Subject: Re: [Intel-gfx] [topic/core-for-ci v2] iommu/vt-d: Check domain flags
> > > before setting snp bit in page-control
> > >
> > > On Thu, 24 Aug 2023, Radhakrishna Sripada
> <radhakrishna.sripada at intel.com>
> > > wrote:
> > > > From: Ashok Raj <ashok.raj at intel.com>
> > > >
> > >
> > > The *why* goes here, along with a link to a gitlab issue.
> > >
> > > Please don't expect topic/core-for-ci to have lower standards than any
> > > other branches. That's not the case. On the contrary, you'll need the
> > > *additional* justification for the commit being in topic/core-for-ci,
> > > and the gitlab issue.
> > >
> > >
> > > BR,
> > > Jani.
> > >
> > >
> > > > Signed-off-by: Ashok Raj <ashok.raj at intel.com>
> > > > Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada at intel.com>
> > > > ---
> > > >  drivers/iommu/intel/iommu.c | 2 +-
> > > >  drivers/iommu/intel/pasid.c | 2 +-
> > > >  2 files changed, 2 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> > > > index 5c8c5cdc36cf..71da6f818e96 100644
> > > > --- a/drivers/iommu/intel/iommu.c
> > > > +++ b/drivers/iommu/intel/iommu.c
> > > > @@ -2150,7 +2150,7 @@ __domain_mapping(struct dmar_domain
> *domain,
> > > unsigned long iov_pfn,
> > > >  	if ((prot & (DMA_PTE_READ|DMA_PTE_WRITE)) == 0)
> > > >  		return -EINVAL;
> > > >
> > > > -	attr = prot & (DMA_PTE_READ | DMA_PTE_WRITE | DMA_PTE_SNP);
> > > > +	attr = prot & (DMA_PTE_READ | DMA_PTE_WRITE);
> > > >  	attr |= DMA_FL_PTE_PRESENT;
> > > >  	if (domain->use_first_level) {
> > > >  		attr |= DMA_FL_PTE_XD | DMA_FL_PTE_US |
> > > DMA_FL_PTE_ACCESS;
> > > > diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
> > > > index c5d479770e12..a057ecf84d82 100644
> > > > --- a/drivers/iommu/intel/pasid.c
> > > > +++ b/drivers/iommu/intel/pasid.c
> > > > @@ -538,7 +538,7 @@ int intel_pasid_setup_first_level(struct intel_iommu
> > > *iommu,
> > > >  	if (flags & PASID_FLAG_FL5LP)
> > > >  		pasid_set_flpm(pte, 1);
> > > >
> > > > -	if (flags & PASID_FLAG_PAGE_SNOOP)
> > > > +	if ((flags & PASID_FLAG_PAGE_SNOOP) && ecap_sc_support(iommu-
> > > >ecap))
> > > >  		pasid_set_pgsnp(pte);
> > > >
> > > >  	pasid_set_domain_id(pte, did);
> > >
> > > --
> > > Jani Nikula, Intel Open Source Graphics Center