From: Jason Gunthorpe <jgg@ziepe.ca>
To: Shyam Saini <shyamsaini@linux.microsoft.com>
Cc: iommu@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
devicetree@vger.kernel.org, virtualization@lists.linux.dev,
will@kernel.org, jacob.pan@linux.microsoft.com,
eric.auger@redhat.com, code@tyhicks.com,
eahariha@linux.microsoft.com, vijayb@linux.microsoft.com,
bboscaccy@linux.microsoft.com, robh@kernel.org,
saravanak@google.com, krzk+dt@kernel.org, conor+dt@kernel.org,
lizhi.hou@amd.com, clement.leger@bootlin.com
Subject: Re: [PATCH v3 2/3] iommu/of: fix device tree configuration for PCI devices
Date: Thu, 14 Aug 2025 21:39:58 -0300 [thread overview]
Message-ID: <20250815003958.GE599331@ziepe.ca> (raw)
In-Reply-To: <20250814233018.GA31418@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net>
On Thu, Aug 14, 2025 at 04:30:18PM -0700, Shyam Saini wrote:
> or were you referring to [2]?
>
> In that case, the PCI child node data needs to be parsed, which is
> currently handled individually by each host controller driver.
Yes, this looks like it may be what I was thinking of, the pci@1,0
specifes the BDF effectively
> This might not be a strong argument, but since firmware updates tend
> to happen less frequently than OS updates, any addition or modification
> to the FDT would require a firmware update. Wouldn't it be more
> maintainable to keep this logic in Linux, which is easier to update
> and typically updated more often?
The DT is supposed to describe the HW, if the PCI device has an issue
with its dma ranges then it seems reasonable to me the FW will use the
existing standards based way to describe that issue?
Presumably this is a fixed issue of the platform. You never did
explain how your system has such werdio behavior, or how something
like iommu=pt can function on it...
Jason
next prev parent reply other threads:[~2025-08-15 0:40 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-06 21:55 [PATCH v3 0/3] arm-smmu: select suitable MSI IOVA Shyam Saini
2025-08-06 21:55 ` [PATCH v3 1/3] arm-smmu: move MSI_IOVA macro definitions Shyam Saini
2025-08-07 14:32 ` kernel test robot
2025-08-06 21:55 ` [PATCH v3 2/3] iommu/of: fix device tree configuration for PCI devices Shyam Saini
2025-08-08 12:15 ` Jason Gunthorpe
2025-08-14 23:30 ` Shyam Saini
2025-08-15 0:39 ` Jason Gunthorpe [this message]
2025-08-15 2:32 ` Shyam Saini
2025-08-18 15:53 ` Jason Gunthorpe
2025-08-26 1:15 ` Shyam Saini
2025-08-26 12:36 ` Jason Gunthorpe
2025-08-26 22:19 ` Shyam Saini
2025-08-06 21:55 ` [PATCH v3 3/3] arm-smmu: select suitable MSI IOVA Shyam Saini
2025-08-06 23:58 ` Jason Gunthorpe
2025-08-07 17:55 ` kernel test robot
2025-08-11 22:34 ` Jacob Pan
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