Hi Lennert,
On 7/18/2021 7:47 PM, Lennert Buytenhek wrote:
On an AMD system, I/O page faults are usually logged like this:
....
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index 811a49a95d04..7ae426b092f2 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -483,7 +483,7 @@ static void amd_iommu_report_page_fault(u16 devid, u16
domain_id,
if (dev_data && __ratelimit(&dev_data->rs)) {
pci_err(pdev, "Event logged [IO_PAGE_FAULT domain=0x%04x
address=0x%llx flags=0x%04x]\n",
domain_id, address, flags);
- } else if (printk_ratelimit()) {
+ } else if (!dev_data && printk_ratelimit()) {
This seems a bit confusing. Also, according to the following comment in
include/linux/printk.h:
/*
* Please don't use printk_ratelimit(), because it shares ratelimiting state
* with all other unrelated printk_ratelimit() callsites. Instead use
* printk_ratelimited() or plain old __ratelimit().
*/
We probably should move away from using printk_ratelimit() here.
What about the following change instead?
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index 811a49a95d04..8eb5d3519743 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -480,11 +480,12 @@ static void amd_iommu_report_page_fault(u16 devid, u16
domain_id,
if (pdev)
dev_data = dev_iommu_priv_get(&pdev->dev);
- if (dev_data && __ratelimit(&dev_data->rs)) {
- pci_err(pdev, "Event logged [IO_PAGE_FAULT domain=0x%04x
address=0x%llx flags=0x%04x]\n",
- domain_id, address, flags);
- } else if (printk_ratelimit()) {
- pr_err("Event logged [IO_PAGE_FAULT device=%02x:%02x.%x
domain=0x%04x address=0x%llx flags=0x%04x]\n",
+ if (dev_data) {
+ if (__ratelimit(&dev_data->rs))
+ pci_err(pdev, "Event logged [IO_PAGE_FAULT domain=0x%04x
address=0x%llx flags=0x%04x]\n",
+ domain_id, address, flags);
+ } else {
+ pr_err_ratelimited("Event logged [IO_PAGE_FAULT device=%02x:%02x.%x
domain=0x%04x address=0x%llx flags=0x%04x]\n",
PCI_BUS_NUM(devid), PCI_SLOT(devid), PCI_FUNC(devid),
domain_id, address, flags);
}
Note also that there might be other places in this file that would need similar
modification as well.
Thanks,
Suravee
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