From: Xingang Wang <wangxinga...@huawei.com>
When request ACS for PCI device in of_iommu_configure, the pci device
has already been scanned and added with 'pci_acs_enable=0'. So the
pci_request_acs() in current procedure does not work for enabling ACS.
Besides, the ACS should be enabled only if there's an IOMMU in system.
So this fix the call of pci_request_acs() and call pci_enable_acs() to
make sure ACS is enabled for the pci_device.
Fixes: 6bf6c24720d33 ("iommu/of: Request ACS from the PCI core when
configuring IOMMU linkage")
Signed-off-by: Xingang Wang <wangxinga...@huawei.com>
---
drivers/iommu/of_iommu.c | 10 +++++++++-
drivers/pci/pci.c | 2 +-
include/linux/pci.h | 1 +
3 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index a9d2df001149..dc621861ae72 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 {
@@ -222,6 +221,15 @@ const struct iommu_ops *of_iommu_configure(struct device
*dev,
/* The fwspec pointer changed, read it again */
fwspec = dev_iommu_fwspec_get(dev);
ops = fwspec->ops;
+
+ /*
+ * If we found an IOMMU and the device is pci,
+ * make sure we enable ACS.
+ */
+ if (dev_is_pci(dev)) {
+ pci_request_acs();
+ pci_enable_acs(to_pci_dev(dev));
+ }
}
/*
* If we have reason to believe the IOMMU driver missed the initial
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index b717680377a9..4e4f98ee2870 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -926,7 +926,7 @@ static void pci_std_enable_acs(struct pci_dev *dev)
* pci_enable_acs - enable ACS if hardware support it
* @dev: the PCI device
*/
-static void pci_enable_acs(struct pci_dev *dev)
+void pci_enable_acs(struct pci_dev *dev)
{
if (!pci_acs_enable)
goto disable_acs_redir;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index c20211e59a57..e6a8bfbc9c98 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -2223,6 +2223,7 @@ static inline struct pci_dev *pcie_find_root_port(struct
pci_dev *dev)
}
void pci_request_acs(void);
+void pci_enable_acs(struct pci_dev *dev);
bool pci_acs_enabled(struct pci_dev *pdev, u16 acs_flags);
bool pci_acs_path_enabled(struct pci_dev *start,
struct pci_dev *end, u16 acs_flags);
--
2.19.1
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