From: Jason Gunthorpe <jgg@nvidia.com>
To: "Suthikulpanit, Suravee" <suravee.suthikulpanit@amd.com>
Cc: linux-kernel@vger.kernel.org, iommu@lists.linux.dev,
joro@8bytes.org, robin.murphy@arm.com, vasant.hegde@amd.com,
ubizjak@gmail.com, jon.grimm@amd.com, santosh.shukla@amd.com,
pandoh@google.com, kumaranand@google.com
Subject: Re: [PATCH v3 1/5] iommu/amd: Disable AMD IOMMU if CMPXCHG16B feature is not supported
Date: Mon, 23 Sep 2024 15:13:25 -0300 [thread overview]
Message-ID: <20240923181325.GG9417@nvidia.com> (raw)
In-Reply-To: <5ff8adab-42c9-403e-9822-8f4fbc259d07@amd.com>
On Mon, Sep 16, 2024 at 11:11:46PM +0700, Suthikulpanit, Suravee wrote:
> > Avoiding flushing is only possible if the full 256 bits are read
> > atomically.
>
> I have verified with the hardware designer, and they have now confirmed that
> the IOMMU hardware has always been implemented with 256-bit read. The next
> revision of the IOMMU spec will be updated to correctly describe this part.
> Therefore, I will update the commit message and implement the code
> accordingly.
That is certainly convenient, except qemu doesn't follow that spec :\
Jason
next prev parent reply other threads:[~2024-09-23 18:13 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-06 12:13 [PATCH v3 0/5] iommu/amd: Use 128-bit cmpxchg operation to update DTE Suravee Suthikulpanit
2024-09-06 12:13 ` [PATCH v3 1/5] iommu/amd: Disable AMD IOMMU if CMPXCHG16B feature is not supported Suravee Suthikulpanit
2024-09-06 16:38 ` Jason Gunthorpe
2024-09-09 15:16 ` Jason Gunthorpe
2024-09-16 17:19 ` Suthikulpanit, Suravee
2024-09-16 16:11 ` Suthikulpanit, Suravee
2024-09-23 18:13 ` Jason Gunthorpe [this message]
2024-09-06 12:13 ` [PATCH v3 2/5] iommu/amd: Introduce helper functions to access and update 256-bit DTE Suravee Suthikulpanit
2024-09-06 15:53 ` Jacob Pan
2024-09-06 17:00 ` Jason Gunthorpe
2024-09-16 16:12 ` Suthikulpanit, Suravee
[not found] ` <66db2589.170a0220.6f57.d691SMTPIN_ADDED_BROKEN@mx.google.com>
2024-09-06 19:31 ` Uros Bizjak
2024-09-07 13:36 ` kernel test robot
2024-09-06 12:13 ` [PATCH v3 3/5] iommu/amd: Modify set_dte_entry() to use 256-bit DTE helpers Suravee Suthikulpanit
2024-09-06 12:13 ` [PATCH v3 4/5] iommu/amd: Modify clear_dte_entry() to avoid in-place update Suravee Suthikulpanit
2024-09-06 18:07 ` Jason Gunthorpe
2024-09-06 12:13 ` [PATCH v3 5/5] iommu/amd: Do not update DTE in-place in amd_iommu_set_dirty_tracking and set_dte_irq_entry Suravee Suthikulpanit
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