[Xen-changelog] [xen-unstable] AMD IOMMU: Reset tail and head pointer of cmd buffer and event log

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1231859806 0
# Node ID 73770182aee48e79a2caa441ad1013982deefddb
# Parent  1c6642adaeb204495c95ab86c8aee41587a22928
AMD IOMMU: Reset tail and head pointer of cmd buffer and event log

Reset the tail and the head pointers of command buffer and event log
to zero in case that iommu does not reset them after the base
addresses of those buffers are updated.

Signed-off-by: Wei Wang <wei.wang2@xxxxxxx>
---
 xen/drivers/passthrough/amd/iommu_init.c |    8 ++++++++
 1 files changed, 8 insertions(+)

diff -r 1c6642adaeb2 -r 73770182aee4 xen/drivers/passthrough/amd/iommu_init.c
--- a/xen/drivers/passthrough/amd/iommu_init.c  Tue Jan 13 15:16:07 2009 +0000
+++ b/xen/drivers/passthrough/amd/iommu_init.c  Tue Jan 13 15:16:46 2009 +0000
@@ -195,6 +195,10 @@ static void __init set_iommu_command_buf
                          IOMMU_CONTROL_COMMAND_BUFFER_ENABLE_MASK,
                          IOMMU_CONTROL_COMMAND_BUFFER_ENABLE_SHIFT, &entry);
     writel(entry, iommu->mmio_base+IOMMU_CONTROL_MMIO_OFFSET);
+
+    /*reset head and tail pointer */
+    writel(0x0, iommu->mmio_base + IOMMU_CMD_BUFFER_HEAD_OFFSET);
+    writel(0x0, iommu->mmio_base + IOMMU_CMD_BUFFER_TAIL_OFFSET);
 }
 
 static void __init register_iommu_exclusion_range(struct amd_iommu *iommu)
@@ -259,6 +263,10 @@ static void __init set_iommu_event_log_c
                          IOMMU_CONTROL_COMP_WAIT_INT_MASK,
                          IOMMU_CONTROL_COMP_WAIT_INT_SHIFT, &entry);
     writel(entry, iommu->mmio_base+IOMMU_CONTROL_MMIO_OFFSET);
+
+    /*reset head and tail pointer */
+    writel(0x0, iommu->mmio_base + IOMMU_EVENT_LOG_HEAD_OFFSET);
+    writel(0x0, iommu->mmio_base + IOMMU_EVENT_LOG_TAIL_OFFSET);
 }
 
 static int amd_iommu_read_event_log(struct amd_iommu *iommu, u32 event[])

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