-----Original Message-----
From: Jason Gunthorpe <jgg@nvidia.com>
Sent: Friday, August 9, 2024 4:12 PM
To: Shameerali Kolothum Thodi <redacted>
Cc: acpica-devel@lists.linux.dev; Alex Williamson
[off-list ref]; Guohanjun (Hanjun Guo)
[off-list ref]; iommu@lists.linux.dev; Joerg Roedel
[off-list ref]; Kevin Tian [off-list ref]; kvm@vger.kernel.org;
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Murphy [off-list ref]; Sudeep Holla [off-list ref];
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patches@lists.linux.dev
Subject: Re: [PATCH 2/8] iommu/arm-smmu-v3: Use S2FWB when available

On Fri, Aug 09, 2024 at 02:26:13PM +0000, Shameerali Kolothum Thodi wrote:

quoted

quoted

+		if (smmu->features & ARM_SMMU_FEAT_S2FWB)
+			pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_ARM_S2FWB;

This probably requires an update in arm_64_lpae_alloc_pgtable_s2() quirks

check.

Yep, fixed I was hoping you had HW to test this..

Let me see if I can get hold of a test setup that supports S2FWB.

I do have another concern with respect to the hardware we have which doesn't
support S2FWB, but those can claim CANWBS. The problem is, BIOS update is not
a very liked/feasible solution to already deployed ones. But we can probably add 
an option/quirk in SMMUv3 driver for those platforms(based on 
ACPI_IORT_SMMU_V3_HISILICON_HI161X).  I hope this is fine.

Thanks,
Shameer