From: Greg KH <gregkh@linuxfoundation.org>
To: Douglas Anderson <dianders@chromium.org>
Cc: rafael@kernel.org, rafael.j.wysocki@intel.com, will@kernel.org,
robin.murphy@arm.com, joro@8bytes.org,
bjorn.andersson@linaro.org, ulf.hansson@linaro.org,
adrian.hunter@intel.com, bhelgaas@google.com,
robdclark@chromium.org, linux-arm-msm@vger.kernel.org,
linux-pci@vger.kernel.org, quic_c_gdjako@quicinc.com,
iommu@lists.linux-foundation.org, sonnyrao@chromium.org,
saiprakash.ranjan@codeaurora.org, linux-mmc@vger.kernel.org,
vbadigan@codeaurora.org, rajatja@google.com,
saravanak@google.com, joel@joelfernandes.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/6] PCI: Indicate that we want to force strict DMA for untrusted devices
Date: Thu, 24 Jun 2021 15:38:18 +0200 [thread overview]
Message-ID: <YNSKyu/a8S3Qywbc@kroah.com> (raw)
In-Reply-To: <20210621165230.3.I7accc008905590bb2b46f40f91a4aeda5b378007@changeid>
On Mon, Jun 21, 2021 at 04:52:45PM -0700, Douglas Anderson wrote:
> At the moment the generic IOMMU framework reaches into the PCIe device
> to check the "untrusted" state and uses this information to figure out
> if it should be running the IOMMU in strict or non-strict mode. Let's
> instead set the new boolean in "struct device" to indicate when we
> want forced strictness.
>
> NOTE: we still continue to set the "untrusted" bit in PCIe since that
> apparently is used for more than just IOMMU strictness. It probably
> makes sense for a later patchset to clarify all of the other needs we
> have for "untrusted" PCIe devices (perhaps add more booleans into the
> "struct device") so we can fully eliminate the need for the IOMMU
> framework to reach into a PCIe device.
It feels like the iommu code should not be messing with pci devices at
all, please don't do this.
Why does this matter? Why wouldn't a pci device use "strict" iommu at
all times? What happens if it does not? Why are PCI devices special?
greg k-h
next prev parent reply other threads:[~2021-06-24 13:38 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-21 23:52 [PATCH 0/6] iommu: Enable devices to request non-strict DMA, starting with QCom SD/MMC Douglas Anderson
2021-06-21 23:52 ` [PATCH 1/6] drivers: base: Add the concept of "pre_probe" to drivers Douglas Anderson
2021-06-24 13:35 ` Greg KH
2021-06-21 23:52 ` [PATCH 2/6] drivers: base: Add bits to struct device to control iommu strictness Douglas Anderson
2021-06-24 13:36 ` Greg KH
2021-06-24 13:42 ` Doug Anderson
2021-06-21 23:52 ` [PATCH 3/6] PCI: Indicate that we want to force strict DMA for untrusted devices Douglas Anderson
2021-06-24 13:38 ` Greg KH [this message]
2021-06-24 13:46 ` Doug Anderson
2021-06-21 23:52 ` [PATCH 4/6] iommu: Combine device strictness requests with the global default Douglas Anderson
2021-06-22 2:03 ` Lu Baolu
2021-06-22 16:53 ` Doug Anderson
2021-06-22 17:01 ` Doug Anderson
2021-06-22 2:55 ` Saravana Kannan
2021-06-22 16:40 ` Doug Anderson
2021-06-22 19:50 ` Saravana Kannan
2021-06-22 11:49 ` Robin Murphy
2021-06-22 18:45 ` Rajat Jain
2021-06-22 19:35 ` Doug Anderson
2021-06-21 23:52 ` [PATCH 5/6] iommu: Stop reaching into PCIe devices to decide strict vs. non-strict Douglas Anderson
2021-06-21 23:52 ` [PATCH 6/6] mmc: sdhci-msm: Request non-strict IOMMU mode Douglas Anderson
2021-06-24 13:43 ` Greg KH
2021-06-24 14:00 ` Doug Anderson
2021-06-22 11:35 ` [PATCH 0/6] iommu: Enable devices to request non-strict DMA, starting with QCom SD/MMC Robin Murphy
2021-06-22 16:06 ` Doug Anderson
2021-06-22 20:02 ` Rob Herring
2021-06-22 20:05 ` Saravana Kannan
2021-06-22 20:10 ` Doug Anderson
2021-06-23 13:54 ` Rob Herring
2021-06-22 22:10 ` Robin Murphy
2021-06-23 17:29 ` Doug Anderson
2021-06-24 17:23 ` Doug Anderson
2021-06-22 17:39 ` John Garry
2021-06-22 19:50 ` Doug Anderson
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