From: Joerg Roedel <[email protected]>
The polling loop for the register change in iommu_ga_log_enable() needs
to have a udelay() in it. Otherwise the CPU might be faster than the
IOMMU hardware and wrongly trigger the WARN_ON() further down the code
stream.
Fixes: 8bda0cfbdc1a ("iommu/amd: Detect and initialize guest vAPIC log")
Signed-off-by: Joerg Roedel <[email protected]>
---
drivers/iommu/amd/init.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index dc338acf3338..d2e09d53851f 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -834,6 +834,7 @@ static int iommu_ga_log_enable(struct amd_iommu *iommu)
status = readl(iommu->mmio_base + MMIO_STATUS_OFFSET);
if (status & (MMIO_STATUS_GALOG_RUN_MASK))
break;
+ udelay(1);
}
if (WARN_ON(i >= LOOP_TIMEOUT))
--
2.34.1
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