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Subject[PATCH 7/8] x86/amd-iommu: Panic if IOMMU command buffer reset fails
Date
To prevent the driver from doing recursive command buffer
resets, just panic when that recursion happens.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
arch/x86/include/asm/amd_iommu_types.h | 3 +++
arch/x86/kernel/amd_iommu.c | 7 +++++++
2 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/amd_iommu_types.h b/arch/x86/include/asm/amd_iommu_types.h
index c54bc97..e676746 100644
--- a/arch/x86/include/asm/amd_iommu_types.h
+++ b/arch/x86/include/asm/amd_iommu_types.h
@@ -337,6 +337,9 @@ struct amd_iommu {
/* if one, we need to send a completion wait command */
bool need_sync;

+ /* becomes true if a command buffer reset is running */
+ bool reset_in_progress;
+
/* default dma_ops domain for that IOMMU */
struct dma_ops_domain *default_dom;
};
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 2333d61..b62a2f6 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -553,9 +553,16 @@ static void reset_iommu_command_buffer(struct amd_iommu *iommu)
{
pr_err("AMD-Vi: Resetting IOMMU command buffer\n");

+ if (iommu->reset_in_progress)
+ panic("AMD-Vi: ILLEGAL_COMMAND_ERROR while resetting command buffer\n");
+
+ iommu->reset_in_progress = true;
+
amd_iommu_reset_cmd_buffer(iommu);
flush_all_devices_for_iommu(iommu);
flush_all_domains_on_iommu(iommu);
+
+ iommu->reset_in_progress = false;
}

/****************************************************************************
--
1.6.3.3



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