On Wed, Mar 28, 2018 at 09:39:40AM -0500, Timur Tabi wrote: > 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; > + }
This needs to be predicated on the disable_bypass option, otherwise I think it will cause regressions for systems that rely on passthrough. Will _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
