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448179e33e
Currently the virtio-iommu device must be programmed before it allows DMA from any PCI device. This can make the VM entirely unusable when a virtio-iommu driver isn't present, for example in a bootloader that loads the OS from storage. Similarly to the other vIOMMU implementations, default to DMA bypassing the IOMMU during boot. Add a "boot-bypass" property, defaulting to true, that lets users change this behavior. Replace the VIRTIO_IOMMU_F_BYPASS feature, which didn't support bypass before feature negotiation, with VIRTIO_IOMMU_F_BYPASS_CONFIG. We add the bypass field to the migration stream without introducing subsections, based on the assumption that this virtio-iommu device isn't being used in production enough to require cross-version migration at the moment (all previous version required workarounds since they didn't support ACPI and boot-bypass). Reviewed-by: Eric Auger <eric.auger@redhat.com> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> Message-Id: <20220214124356.872985-3-jean-philippe@linaro.org> Acked-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Tested-by: Eric Auger <eric.auger@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>