[+cc Marek, Anders, Robin] On Fri, Aug 20, 2021 at 02:57:12PM -0500, Bjorn Helgaas wrote: > On Fri, May 21, 2021 at 03:03:24AM +0000, Wang Xingang wrote: > > From: Xingang Wang <wangxingang5@xxxxxxxxxx> > > > > 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@xxxxxxxxxx> > > Applied to pci/virtualization for v5.15, thanks! I dropped this for now, until the problems reported by Marek and Anders get sorted out. > > --- > > drivers/iommu/of_iommu.c | 1 - > > drivers/pci/of.c | 8 +++++++- > > 2 files changed, 7 insertions(+), 2 deletions(-) > > > > 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 > >