[Xen-devel] [PATCH][IOMMU] Debug info for AMD IOMMU event log

[Wei Huang <wei.huang2@xxxxxxx>]

The attached patch is to print out the event log entry content for debug's 
purpose. Additionally, when IOMMU reset event log (due to event log overflow), 
we should print out the event log content for debugging.

Signed-off-by: Wei Huang <wei.huang2@xxxxxxx>
Signed-off-by: Wei Wang <wei.wang2@xxxxxxx>


diff -r a7a680442b73 xen/drivers/passthrough/amd/iommu_init.c
--- a/xen/drivers/passthrough/amd/iommu_init.c  Thu Jul 08 09:56:10 2010 +0100
+++ b/xen/drivers/passthrough/amd/iommu_init.c  Fri Jul 09 11:52:09 2010 -0500
@@ -270,42 +270,6 @@
     writel(entry, iommu->mmio_base + IOMMU_CONTROL_MMIO_OFFSET);
 }
 
-static void amd_iommu_reset_event_log(struct amd_iommu *iommu)
-{
-    u32 entry;
-    int log_run;
-    int loop_count = 1000;
-
-    /* wait until EventLogRun bit = 0 */
-    do {
-        entry = readl(iommu->mmio_base + IOMMU_STATUS_MMIO_OFFSET);
-        log_run = get_field_from_reg_u32(entry,
-                                        IOMMU_STATUS_EVENT_LOG_RUN_MASK,
-                                        IOMMU_STATUS_EVENT_LOG_RUN_SHIFT);
-        loop_count--;
-    } while ( log_run && loop_count );
-
-    if ( log_run )
-    {
-        AMD_IOMMU_DEBUG("Warning: EventLogRun bit is not cleared"
-                       "before reset!\n");
-        return;
-    }
-
-    set_iommu_event_log_control(iommu, IOMMU_CONTROL_DISABLED);
-
-    /*clear overflow bit */
-    set_field_in_reg_u32(IOMMU_CONTROL_DISABLED, entry,
-                         IOMMU_STATUS_EVENT_OVERFLOW_MASK,
-                         IOMMU_STATUS_EVENT_OVERFLOW_SHIFT, &entry);
-    writel(entry, iommu->mmio_base+IOMMU_STATUS_MMIO_OFFSET);
-
-    /*reset event log base address */
-    iommu->event_log_head = 0;
-
-    set_iommu_event_log_control(iommu, IOMMU_CONTROL_ENABLED);
-}
-
 static void parse_event_log_entry(u32 entry[]);
 
 static int amd_iommu_read_event_log(struct amd_iommu *iommu)
@@ -340,6 +304,45 @@
     }
 
     return 0;
+}
+
+static void amd_iommu_reset_event_log(struct amd_iommu *iommu)
+{
+    u32 entry;
+    int log_run;
+    int loop_count = 1000;
+
+    /* wait until EventLogRun bit = 0 */
+    do {
+        entry = readl(iommu->mmio_base + IOMMU_STATUS_MMIO_OFFSET);
+        log_run = get_field_from_reg_u32(entry,
+                                        IOMMU_STATUS_EVENT_LOG_RUN_MASK,
+                                        IOMMU_STATUS_EVENT_LOG_RUN_SHIFT);
+        loop_count--;
+    } while ( log_run && loop_count );
+
+    if ( log_run )
+    {
+        AMD_IOMMU_DEBUG("Warning: EventLogRun bit is not cleared"
+                       "before reset!\n");
+        return;
+    }
+
+    set_iommu_event_log_control(iommu, IOMMU_CONTROL_DISABLED);
+
+    /* read event log for debugging */
+    amd_iommu_read_event_log(iommu);
+
+    /*clear overflow bit */
+    set_field_in_reg_u32(IOMMU_CONTROL_DISABLED, entry,
+                         IOMMU_STATUS_EVENT_OVERFLOW_MASK,
+                         IOMMU_STATUS_EVENT_OVERFLOW_SHIFT, &entry);
+    writel(entry, iommu->mmio_base+IOMMU_STATUS_MMIO_OFFSET);
+
+    /*reset event log base address */
+    iommu->event_log_head = 0;
+
+    set_iommu_event_log_control(iommu, IOMMU_CONTROL_ENABLED);
 }
 
 static void iommu_msi_set_affinity(unsigned int irq, cpumask_t mask)
@@ -491,6 +494,11 @@
         printk(XENLOG_ERR "AMD_IOV: "
             "%s: domain:%d, device id:0x%x, fault address:0x%"PRIx64"\n",
             event_str[code-1], domain_id, device_id, *addr);
+    }
+    else
+    {
+        AMD_IOMMU_DEBUG("event 0x%08x 0x%08x 0x%08x 0x%08x\n", entry[0],
+                        entry[1], entry[2], entry[3]);
     }
 }
 

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