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tlsNG-d25034/1778086531-E357FCF5-CA28E968/0/0 X-purgate-type: clean X-purgate-size: 983 On Wed, May 06, 2026 at 06:49:47PM +0200, Marek Marczykowski-Górecki wrote: > On Wed, May 06, 2026 at 03:55:12PM +0200, Roger Pau Monne wrote: > > Hello, > > > > Unconditionally zeroing the whole IOMMU MMIO region is dangerous, at > > least on an upcoming platform this does put the IOMMU in a broken state > > that's not recoverable by the init procedure in Xen. > > > > Get rid of the zeroing, and instead attempt to disable the IOMMU ahead > > of enabling it. > > Just to mention it here, while this looks like a step in the right > direction, even better would be to not disable IOMMU at boot, but > reconfigure it - to preserve uninterrupted protection when boot time DMA > protection is enabled in firmware. But that's definitely more work... Yes, we are aware of this. But IMO booting with the IOMMU enabled will be a new feature, this is strictly a fix that we can "safely" backport to stable branches to deal with broken hardware. Thanks, Roger.