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From:   Han Jingoo <jingoohan1@gmail.com>
Date:   Thu, 11 Aug 2022 19:46:27 -0700
Message-ID: <CAPOBaE5_teX6-39ofwC=YG3scc4dT+S47sQNUZYeu7WMzpe1mQ@mail.gmail.com>
Subject: Re: [PATCH v4 2/2] PCI: dwc: Add support for 64-bit MSI target address
To:     Will McVicker <willmcvicker@google.com>
Cc:     Gustavo Pimentel <gustavo.pimentel@synopsys.com>,
        Lorenzo Pieralisi <lpieralisi@kernel.org>,
        Rob Herring <robh@kernel.org>,
        =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= <kw@linux.com>,
        Bjorn Helgaas <bhelgaas@google.com>, kernel-team@android.com,
        Vidya Sagar <vidyas@nvidia.com>,
        Christoph Hellwig <hch@infradead.org>,
        "<linux-pci@vger.kernel.org>" <linux-pci@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        kernel test robot <lkp@intel.com>
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On 08/11/2022, Will McVicker wrote:
> Since not all devices require a 32-bit MSI address, add support to the
> PCIe host driver to allow setting the DMA mask to 64-bits. This allows
> kernels to disable ZONE_DMA32 and bounce buffering (swiotlb) without
> risking not being able to get a 32-bit address during DMA allocation.
> Basically, in the slim chance that there are no 32-bit allocations
> available, the current PCIe host driver will fail to allocate the
> msi_msg page due to a DMA address overflow (seen in [1]). With this
> patch, the PCIe device can advertise 64-bit support via its MSI
> capabilities to hint to the PCIe host driver to set the DMA mask to
> 64-bits.
>
> [1] https://lore.kernel.org/all/Yo0soniFborDl7+C@google.com/
>
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Will McVicker <willmcvicker@google.com>
> Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Jingoo Han <jingoohan1@gmail.com>

> ---
> drivers/pci/controller/dwc/pcie-designware-host.c | 14 ++++++++++++--
> drivers/pci/controller/dwc/pcie-designware.c      |  8 ++++++++
> drivers/pci/controller/dwc/pcie-designware.h      |  1 +
> 3 files changed, 21 insertions(+), 2 deletions(-)
=E2=80=A6..