This is a note to let you know that I've just added the patch titled
iommu/amd: Add workaround for event log erratum
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
iommu-amd-add-workaround-for-event-log-erratum.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 3d06fca8d2aa3543030e40b95f1d62f9f5a03540 Mon Sep 17 00:00:00 2001
From: Joerg Roedel <[email protected]>
Date: Thu, 12 Apr 2012 14:12:00 +0200
Subject: iommu/amd: Add workaround for event log erratum
From: Joerg Roedel <[email protected]>
commit 3d06fca8d2aa3543030e40b95f1d62f9f5a03540 upstream.
Due to a recent erratum it can happen that the head pointer
of the event-log is updated before the actual event-log
entry is written. This patch implements the recommended
workaround.
Signed-off-by: Joerg Roedel <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/iommu/amd_iommu.c | 29 +++++++++++++++++++++++------
1 file changed, 23 insertions(+), 6 deletions(-)
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -450,12 +450,27 @@ static void dump_command(unsigned long p
static void iommu_print_event(struct amd_iommu *iommu, void *__evt)
{
- u32 *event = __evt;
- int type = (event[1] >> EVENT_TYPE_SHIFT) & EVENT_TYPE_MASK;
- int devid = (event[0] >> EVENT_DEVID_SHIFT) & EVENT_DEVID_MASK;
- int domid = (event[1] >> EVENT_DOMID_SHIFT) & EVENT_DOMID_MASK;
- int flags = (event[1] >> EVENT_FLAGS_SHIFT) & EVENT_FLAGS_MASK;
- u64 address = (u64)(((u64)event[3]) << 32) | event[2];
+ int type, devid, domid, flags;
+ volatile u32 *event = __evt;
+ int count = 0;
+ u64 address;
+
+retry:
+ type = (event[1] >> EVENT_TYPE_SHIFT) & EVENT_TYPE_MASK;
+ devid = (event[0] >> EVENT_DEVID_SHIFT) & EVENT_DEVID_MASK;
+ domid = (event[1] >> EVENT_DOMID_SHIFT) & EVENT_DOMID_MASK;
+ flags = (event[1] >> EVENT_FLAGS_SHIFT) & EVENT_FLAGS_MASK;
+ address = (u64)(((u64)event[3]) << 32) | event[2];
+
+ if (type == 0) {
+ /* Did we hit the erratum? */
+ if (++count == LOOP_TIMEOUT) {
+ pr_err("AMD-Vi: No event written to event log\n");
+ return;
+ }
+ udelay(1);
+ goto retry;
+ }
printk(KERN_ERR "AMD-Vi: Event logged [");
@@ -508,6 +523,8 @@ static void iommu_print_event(struct amd
default:
printk(KERN_ERR "UNKNOWN type=0x%02x]\n", type);
}
+
+ memset(__evt, 0, 4 * sizeof(u32));
}
static void iommu_poll_events(struct amd_iommu *iommu)
Patches currently in stable-queue which might be from [email protected] are
queue-3.4/iommu-amd-check-for-the-right-tlp-prefix-bit.patch
queue-3.4/iommu-amd-add-workaround-for-event-log-erratum.patch
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