Re: [PATCH v4] iommu/of: Fix pci_request_acs() before enumerating PCI devices

[Xingang Wang <wangxingang5@huawei.com>]

Hi everyone,

On 2021/5/22 3:03, Rob Herring wrote:
> On Thu, May 20, 2021 at 10:03 PM Wang Xingang <wangxingang5@huawei.com> wrote:
>>
>> From: Xingang Wang <wangxingang5@huawei.com>
>>
>> When booting with devicetree, the pci_request_acs() is called after the
>> enumeration and initialization of PCI devices, thus the ACS is not
>> enabled. And ACS should be enabled when IOMMU is detected for the
>> PCI host bridge, so add check for IOMMU before probe of PCI host and call
>> pci_request_acs() to make sure ACS will be enabled when enumerating PCI
>> devices.
>>
>> Fixes: 6bf6c24720d33 ("iommu/of: Request ACS from the PCI core when
>> configuring IOMMU linkage")
>> Signed-off-by: Xingang Wang <wangxingang5@huawei.com>
>> ---
>>   drivers/iommu/of_iommu.c | 1 -
>>   drivers/pci/of.c         | 8 +++++++-
>>   2 files changed, 7 insertions(+), 2 deletions(-)
> 
> Reviewed-by: Rob Herring <robh@kernel.org>
> 

Ping, is this patch appropriate for mainline?

>> diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
>> index a9d2df001149..54a14da242cc 100644
>> --- a/drivers/iommu/of_iommu.c
>> +++ b/drivers/iommu/of_iommu.c
>> @@ -205,7 +205,6 @@ const struct iommu_ops *of_iommu_configure(struct device *dev,
>>                          .np = master_np,
>>                  };
>>
>> -               pci_request_acs();
>>                  err = pci_for_each_dma_alias(to_pci_dev(dev),
>>                                               of_pci_iommu_init, &info);
>>          } else {
>> diff --git a/drivers/pci/of.c b/drivers/pci/of.c
>> index da5b414d585a..2313c3f848b0 100644
>> --- a/drivers/pci/of.c
>> +++ b/drivers/pci/of.c
>> @@ -581,9 +581,15 @@ static int pci_parse_request_of_pci_ranges(struct device *dev,
>>
>>   int devm_of_pci_bridge_init(struct device *dev, struct pci_host_bridge *bridge)
>>   {
>> -       if (!dev->of_node)
>> +       struct device_node *node = dev->of_node;
>> +
>> +       if (!node)
>>                  return 0;
>>
>> +       /* Detect IOMMU and make sure ACS will be enabled */
>> +       if (of_property_read_bool(node, "iommu-map"))
>> +               pci_request_acs();
>> +
>>          bridge->swizzle_irq = pci_common_swizzle;
>>          bridge->map_irq = of_irq_parse_and_map_pci;
>>
>> --
>> 2.19.1
>>
> .
>