From: Sameer Goel <[email protected]> Set SMMU_GBPA to abort all incoming translations during the SMMU reset when SMMUEN==0.
This prevents a race condition where a stray DMA from the crashed primary kernel can try to access an IOVA address as an invalid PA when SMMU is disabled during reset in the crash kernel. Signed-off-by: Sameer Goel <[email protected]> --- drivers/iommu/arm-smmu-v3.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c index 3f2f1fc68b52..c04a89310c59 100644 --- a/drivers/iommu/arm-smmu-v3.c +++ b/drivers/iommu/arm-smmu-v3.c @@ -2458,6 +2458,18 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu, bool bypass) if (reg & CR0_SMMUEN) dev_warn(smmu->dev, "SMMU currently enabled! Resetting...\n"); + /* + * Abort all incoming translations. This can happen in a kdump case + * where SMMU is initialized when a prior DMA is pending. Just + * disabling the SMMU in this case might result in writes to invalid + * PAs. + */ + ret = arm_smmu_update_gbpa(smmu, 1, GBPA_ABORT); + if (ret) { + dev_err(smmu->dev, "GBPA not responding to update\n"); + return ret; + } + ret = arm_smmu_device_disable(smmu); if (ret) return ret; -- Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project. _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
