9dd5e808fc
We used to set the default granule to 4KB but with VFIO assignment it makes more sense to use the actual host page size. Indeed when hotplugging a VFIO device protected by a virtio-iommu on a 64kB/64kB host/guest config, we current get a qemu crash: "vfio: DMA mapping failed, unable to continue" This is due to the hot-attached VFIO device calling memory_region_iommu_set_page_size_mask() with 64kB granule whereas the virtio-iommu granule was already frozen to 4KB on machine init done. Set the granule property to "host" and introduce a new compat. The page size mask used before 9.0 was qemu_target_page_mask(). Since the virtio-iommu currently only supports x86_64 and aarch64, this matched a 4KB granule. Note that the new default will prevent 4kB guest on 64kB host because the granule will be set to 64kB which would be larger than the guest page size. In that situation, the virtio-iommu driver fails on viommu_domain_finalise() with "granule 0x10000 larger than system page size 0x1000". In that case the workaround is to request 4K granule. The current limitation of global granule in the virtio-iommu should be removed and turned into per domain granule. But until we get this upgraded, this new default is probably better because I don't think anyone is currently interested in running a 4KB page size guest with virtio-iommu on a 64KB host. However supporting 64kB guest on 64kB host with virtio-iommu and VFIO looks a more important feature. Signed-off-by: Eric Auger <eric.auger@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com> Message-Id: <20240307134445.92296-4-eric.auger@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> |
||
|---|---|---|
| .. | ||
| bus.c | ||
| clock-vmstate.c | ||
| clock.c | ||
| cpu-common.c | ||
| cpu-sysemu.c | ||
| fw-path-provider.c | ||
| generic-loader.c | ||
| gpio.c | ||
| guest-loader.c | ||
| guest-loader.h | ||
| hotplug-stubs.c | ||
| hotplug.c | ||
| irq.c | ||
| Kconfig | ||
| loader-fit.c | ||
| loader.c | ||
| machine-hmp-cmds.c | ||
| machine-qmp-cmds.c | ||
| machine-smp.c | ||
| machine.c | ||
| meson.build | ||
| nmi.c | ||
| null-machine.c | ||
| numa.c | ||
| or-irq.c | ||
| platform-bus.c | ||
| ptimer.c | ||
| qdev-clock.c | ||
| qdev-fw.c | ||
| qdev-hotplug.c | ||
| qdev-prop-internal.h | ||
| qdev-properties-system.c | ||
| qdev-properties.c | ||
| qdev.c | ||
| register.c | ||
| reset.c | ||
| resetcontainer.c | ||
| resettable.c | ||
| split-irq.c | ||
| stream.c | ||
| sysbus-fdt.c | ||
| sysbus.c | ||
| trace-events | ||
| trace.h | ||
| uboot_image.h | ||
| vm-change-state-handler.c | ||
| vmstate-if.c | ||