From: Bjorn Helgaas <helgaas@kernel.org>
To: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: will@kernel.org, robh+dt@kernel.org, joro@8bytes.org,
baolu.lu@linux.intel.com, sudeep.holla@arm.com,
linux-doc@vger.kernel.org, linux-pci@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
linux-acpi@vger.kernel.org, iommu@lists.linux-foundation.org,
lorenzo.pieralisi@arm.com, corbet@lwn.net, mark.rutland@arm.com,
liviu.dudau@arm.com, guohanjun@huawei.com, rjw@rjwysocki.net,
lenb@kernel.org, robin.murphy@arm.com, dwmw2@infradead.org,
amurray@thegoodpenguin.co.uk, frowand.list@gmail.com
Subject: Re: [PATCH v2 05/11] PCI/ATS: Gather checks into pci_ats_supported()
Date: Thu, 12 Mar 2020 16:01:57 -0500 [thread overview]
Message-ID: <20200312210157.GA180471@google.com> (raw)
In-Reply-To: <20200311124506.208376-6-jean-philippe@linaro.org>
On Wed, Mar 11, 2020 at 01:45:00PM +0100, Jean-Philippe Brucker wrote:
> IOMMU drivers need to perform several tests when checking if a device
> supports ATS. Move them all into a new function that returns true when
> a device and its host bridge support ATS.
>
> Since pci_enable_ats() now calls pci_ats_supported(), the following
> new checks are now common:
> * whether a device is trusted. Devices plugged into external-facing
> ports such as thunderbolt are untrusted.
> * whether the host bridge supports ATS, which defaults to true unless
> the firmware description states that ATS isn't supported by the host
> bridge.
>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
> ---
> drivers/pci/ats.c | 30 +++++++++++++++++++++++++++++-
> include/linux/pci-ats.h | 3 +++
> 2 files changed, 32 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
> index 390e92f2d8d1..bbfd0d42b8b9 100644
> --- a/drivers/pci/ats.c
> +++ b/drivers/pci/ats.c
> @@ -30,6 +30,34 @@ void pci_ats_init(struct pci_dev *dev)
> dev->ats_cap = pos;
> }
>
> +/**
> + * pci_ats_supported - check if the device can use ATS
> + * @dev: the PCI device
> + *
> + * Returns true if the device supports ATS and is allowed to use it, false
> + * otherwise.
> + */
> +bool pci_ats_supported(struct pci_dev *dev)
> +{
> + struct pci_host_bridge *bridge;
> +
> + if (!dev->ats_cap)
> + return false;
> +
> + if (dev->untrusted)
> + return false;
> +
> + bridge = pci_find_host_bridge(dev->bus);
> + if (!bridge)
> + return false;
> +
> + if (!bridge->ats_supported)
> + return false;
> +
> + return true;
I assume this is the same as
return bridge->ats_supported;
Only "assuming" because I'm not a C language lawyer, but I assume it
does the obvious conversion from unsigned:1 to bool.
> +}
next prev parent reply other threads:[~2020-03-12 21:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-11 12:44 [PATCH v2 00/11] PCI/ATS: Device-tree support and other improvements Jean-Philippe Brucker
2020-03-11 12:44 ` [PATCH v2 01/11] dt-bindings: PCI: generic: Add ats-supported property Jean-Philippe Brucker
2020-03-11 12:44 ` [PATCH v2 02/11] PCI: Add ats_supported host bridge flag Jean-Philippe Brucker
2020-03-12 21:21 ` Bjorn Helgaas
2020-03-11 12:44 ` [PATCH v2 03/11] PCI: OF: Check whether the host bridge supports ATS Jean-Philippe Brucker
2020-03-12 20:45 ` Bjorn Helgaas
2020-03-11 12:44 ` [PATCH v2 04/11] ACPI/IORT: Check ATS capability in root complex node Jean-Philippe Brucker
2020-03-12 20:58 ` Bjorn Helgaas
2020-03-11 12:45 ` [PATCH v2 05/11] PCI/ATS: Gather checks into pci_ats_supported() Jean-Philippe Brucker
2020-03-12 21:01 ` Bjorn Helgaas [this message]
2020-03-11 12:45 ` [PATCH v2 06/11] iommu/amd: Use pci_ats_supported() Jean-Philippe Brucker
2020-03-11 12:45 ` [PATCH v2 07/11] iommu/arm-smmu-v3: " Jean-Philippe Brucker
2020-03-18 21:49 ` Will Deacon
2020-03-11 12:45 ` [PATCH v2 08/11] iommu/vt-d: " Jean-Philippe Brucker
2020-03-12 1:44 ` Lu Baolu
2020-03-12 7:54 ` Jean-Philippe Brucker
2020-03-12 8:18 ` Lu Baolu
2020-03-11 12:45 ` [PATCH v2 09/11] ACPI/IORT: Drop ATS fwspec flag Jean-Philippe Brucker
2020-03-11 12:45 ` [PATCH v2 10/11] arm64: dts: fast models: Enable PCIe ATS for Base RevC FVP Jean-Philippe Brucker
2020-03-11 12:45 ` [PATCH v2 11/11] Documentation: Generalize the "pci=noats" boot parameter Jean-Philippe Brucker
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