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From: Jason Gunthorpe <jgg@nvidia.com>
To: Pranjal Shrivastava <praan@google.com>
Cc: "Nicolin Chen" <nicolinc@nvidia.com>,
	"Will Deacon" <will@kernel.org>, "Joerg Roedel" <joro@8bytes.org>,
	"Jean-Philippe Brucker" <jpb@kernel.org>,
	"Robin Murphy" <robin.murphy@arm.com>,
	"Catalin Marinas" <catalin.marinas@arm.com>,
	"Mikołaj Lenczewski" <miko.lenczewski@arm.com>,
	linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] iommu/arm-smmu-v3-sva: Enable Hardware Access and Hardware Dirty bits
Date: Fri, 8 May 2026 09:35:50 -0300	[thread overview]
Message-ID: <20260508123550.GB9254@nvidia.com> (raw)
In-Reply-To: <af0SdkjQOZxnnaQb@google.com>

On Thu, May 07, 2026 at 10:30:14PM +0000, Pranjal Shrivastava wrote:
> > @@ -92,6 +92,16 @@ void arm_smmu_make_sva_cd(struct arm_smmu_cd *target,
> >  
> >  		target->data[1] = cpu_to_le64(virt_to_phys(mm->pgd) &
> >  					      CTXDESC_CD_1_TTB0_MASK);
> > +
> > +		/*
> > +		 * Enable Hardware Access and Dirty updates (DBM) if supported.
> > +		 * This is safe to enable by default, as PTE_WRITE and PTE_DBM
> > +		 * share the same bit.
> > +		 */
> > +		if (master->smmu->features & ARM_SMMU_FEAT_HA)
> > +			target->data[0] |= cpu_to_le64(CTXDESC_CD_0_TCR_HA);
> > +		if (master->smmu->features & ARM_SMMU_FEAT_HD)
> > +			target->data[0] |= cpu_to_le64(CTXDESC_CD_0_TCR_HD);
> 
> IIUC, we should be setting these if IO_PGTABLE_QUIRK_ARM_HD is present?

SVA does not use IO_PGTABLE at all, and it directly constructs its own
CD.

No relation between those two flows.

Jason

  reply	other threads:[~2026-05-08 12:35 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20260503135413.1108138-1-nicolinc@nvidia.com>
2026-05-07 22:30 ` [PATCH] iommu/arm-smmu-v3-sva: Enable Hardware Access and Hardware Dirty bits Pranjal Shrivastava
2026-05-08 12:35   ` Jason Gunthorpe [this message]
2026-05-08 13:12     ` Pranjal Shrivastava
2026-05-08 13:27       ` Jason Gunthorpe
2026-05-08 13:31       ` Robin Murphy
2026-05-08 13:57         ` Pranjal Shrivastava
2026-05-08 14:24           ` Robin Murphy
2026-05-09  7:56             ` Nicolin Chen
2026-05-11 13:22               ` Pranjal Shrivastava
2026-05-11 13:21             ` Pranjal Shrivastava

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