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authorLennert Buytenhek <buytenh@wantstofly.org>2021-09-28 13:44:21 +0300
committerJoerg Roedel <jroedel@suse.de>2021-09-29 14:05:20 +0200
commit9f78e446bde812d18f228976f2c6b8f25b93f08b (patch)
tree44179bd46b7d602459e25cc964afdfbc41dc1fa7 /drivers/iommu
parent5816b3e6577eaa676ceb00a848f0fd65fe2adc29 (diff)
iommu/amd: Use report_iommu_fault()
This patch makes iommu/amd call report_iommu_fault() when an I/O page fault occurs, which has two effects: 1) It allows device drivers to register a callback to be notified of I/O page faults, via the iommu_set_fault_handler() API. 2) It triggers the io_page_fault tracepoint in report_iommu_fault() when an I/O page fault occurs. The latter point is the main aim of this patch, as it allows rasdaemon-like daemons to be notified of I/O page faults, and to possibly initiate corrective action in response. A number of other IOMMU drivers already use report_iommu_fault(), and I/O page faults on those IOMMUs therefore already trigger this tracepoint -- but this isn't yet the case for AMD-Vi and Intel DMAR. The AMD IOMMU specification suggests that the bit in an I/O page fault event log entry that signals whether an I/O page fault was for a read request or for a write request is only meaningful when the faulting access was to a present page, but some testing on a Ryzen 3700X suggests that this bit encodes the correct value even for I/O page faults to non-present pages, and therefore, this patch passes the R/W information up the stack even for I/O page faults to non-present pages. Signed-off-by: Lennert Buytenhek <buytenh@arista.com> Link: https://lore.kernel.org/r/YVLyBW97vZLpOaAp@wantstofly.org Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'drivers/iommu')
-rw-r--r--drivers/iommu/amd/amd_iommu_types.h2
-rw-r--r--drivers/iommu/amd/iommu.c21
2 files changed, 23 insertions, 0 deletions
diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h
index 8dbe61e2b3c1..867535eb0ce9 100644
--- a/drivers/iommu/amd/amd_iommu_types.h
+++ b/drivers/iommu/amd/amd_iommu_types.h
@@ -138,6 +138,8 @@
#define EVENT_DOMID_MASK_HI 0xf0000
#define EVENT_FLAGS_MASK 0xfff
#define EVENT_FLAGS_SHIFT 0x10
+#define EVENT_FLAG_RW 0x020
+#define EVENT_FLAG_I 0x008
/* feature control bits */
#define CONTROL_IOMMU_EN 0x00ULL
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index 1722bb161841..beadcffcc223 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -473,6 +473,12 @@ static void amd_iommu_report_rmp_fault(volatile u32 *event)
pci_dev_put(pdev);
}
+#define IS_IOMMU_MEM_TRANSACTION(flags) \
+ (((flags) & EVENT_FLAG_I) == 0)
+
+#define IS_WRITE_REQUEST(flags) \
+ ((flags) & EVENT_FLAG_RW)
+
static void amd_iommu_report_page_fault(u16 devid, u16 domain_id,
u64 address, int flags)
{
@@ -485,6 +491,20 @@ static void amd_iommu_report_page_fault(u16 devid, u16 domain_id,
dev_data = dev_iommu_priv_get(&pdev->dev);
if (dev_data) {
+ /*
+ * If this is a DMA fault (for which the I(nterrupt)
+ * bit will be unset), allow report_iommu_fault() to
+ * prevent logging it.
+ */
+ if (IS_IOMMU_MEM_TRANSACTION(flags)) {
+ if (!report_iommu_fault(&dev_data->domain->domain,
+ &pdev->dev, address,
+ IS_WRITE_REQUEST(flags) ?
+ IOMMU_FAULT_WRITE :
+ IOMMU_FAULT_READ))
+ goto out;
+ }
+
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);
@@ -495,6 +515,7 @@ static void amd_iommu_report_page_fault(u16 devid, u16 domain_id,
domain_id, address, flags);
}
+out:
if (pdev)
pci_dev_put(pdev);
}