x86/amd-iommu: Reset command buffer if wait loop fails

Instead of a panic on an comletion wait loop failure, try to
recover from that event from resetting the command buffer.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index b62a2f64dfc5..cfca80bfe75f 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -318,8 +318,11 @@ static void __iommu_wait_for_completion(struct amd_iommu *iommu)
         status &= ~MMIO_STATUS_COM_WAIT_INT_MASK;
         writel(status, iommu->mmio_base + MMIO_STATUS_OFFSET);
 
-        if (unlikely(i == EXIT_LOOP_COUNT))
-                panic("AMD IOMMU: Completion wait loop failed\n");
+        if (unlikely(i == EXIT_LOOP_COUNT)) {
+                spin_unlock(&iommu->lock);
+                reset_iommu_command_buffer(iommu);
+                spin_lock(&iommu->lock);
+        }
 }
 
 /*