Re: [PATCH v6 14/14] iommu/arm-smmu-v3: Set MEV bit in nested STE for DoS mitigations

From: Jason Gunthorpe
Date: Tue Feb 18 2025 - 13:57:45 EST


On Tue, Feb 18, 2025 at 06:17:15PM +0000, Pranjal Shrivastava wrote:

> > Is MEV available only in nested mode? Otherwise it perhaps makes
> > sense to turn it on in all configurations in IOMMUFD paths...
>
> I think the arm-smmu-v3's iommufd implementation only supports nested
> which could be the reason.

I think starting with MEV in this limited case is reasonable.

I agree it makes sense to always turn it on from a production
perspective..

Jason