diff options
Diffstat (limited to 'iommu-amd-Fix-loop-timeout-issue-in-iommu_ga_log_enable.patch')
| -rw-r--r-- | iommu-amd-Fix-loop-timeout-issue-in-iommu_ga_log_enable.patch | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/iommu-amd-Fix-loop-timeout-issue-in-iommu_ga_log_enable.patch b/iommu-amd-Fix-loop-timeout-issue-in-iommu_ga_log_enable.patch new file mode 100644 index 000000000000..965a886b472d --- /dev/null +++ b/iommu-amd-Fix-loop-timeout-issue-in-iommu_ga_log_enable.patch @@ -0,0 +1,45 @@ +From 9b45a7738eec52bf0f5d8d3d54e822962781c5f2 Mon Sep 17 00:00:00 2001 +From: Joerg Roedel <jroedel@suse.de> +Date: Fri, 4 Feb 2022 12:55:37 +0100 +Subject: [PATCH] iommu/amd: Fix loop timeout issue in iommu_ga_log_enable() + +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. Use a 10us for udelay(), has there is some hardware where +activation of the GA log can take more than a 100ms. + +A future optimization should move the activation check of the GA log +to the point where it gets used for the first time. But that is a +bigger change and not suitable for a fix. + +Fixes: 8bda0cfbdc1a ("iommu/amd: Detect and initialize guest vAPIC log") +Signed-off-by: Joerg Roedel <jroedel@suse.de> +Link: https://lore.kernel.org/r/20220204115537.3894-1-joro@8bytes.org +--- + drivers/iommu/amd/init.c | 2 ++ + 1 file changed, 2 insertions(+) + +diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c +index dc338acf3338..b10fb52ea442 100644 +--- a/drivers/iommu/amd/init.c ++++ b/drivers/iommu/amd/init.c +@@ -21,6 +21,7 @@ + #include <linux/export.h> + #include <linux/kmemleak.h> + #include <linux/cc_platform.h> ++#include <linux/iopoll.h> + #include <asm/pci-direct.h> + #include <asm/iommu.h> + #include <asm/apic.h> +@@ -834,6 +835,7 @@ 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(10); + } + + if (WARN_ON(i >= LOOP_TIMEOUT)) +-- +2.35.1 + |