Culprit: https://gitlab.com/qemu-project/qemu/-/commit/c7b2e22bd95710e404c393e9f563cfe7404220c1
Fix: https://gitlab.com/qemu-project/qemu/-/commit/dbc0ed56223011281e14b5cb8c02453915d35d12
The bug is included in the v11 release, fix was just merged 4 days ago therefore it is not in any release.
This regression bug causes qemu-kvm's emulated intel-iommu to stop including ECAP.PT bit in its ecap. When guest kernel tries to enable iommu passthrough it have to fall back to manually creating a 1:1 identity memory map, which has a significant performance implication. More details: https://gitlab.com/qemu-project/qemu/-/work_items/3965
Not sure if PVE maintainers can cherry pick this and release a new sub version of pve-qemu-kvm. Fix is clean because the root cause is a coding error.
Fix: https://gitlab.com/qemu-project/qemu/-/commit/dbc0ed56223011281e14b5cb8c02453915d35d12
The bug is included in the v11 release, fix was just merged 4 days ago therefore it is not in any release.
This regression bug causes qemu-kvm's emulated intel-iommu to stop including ECAP.PT bit in its ecap. When guest kernel tries to enable iommu passthrough it have to fall back to manually creating a 1:1 identity memory map, which has a significant performance implication. More details: https://gitlab.com/qemu-project/qemu/-/work_items/3965
Not sure if PVE maintainers can cherry pick this and release a new sub version of pve-qemu-kvm. Fix is clean because the root cause is a coding error.
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