This series fixes various bugs observed when saving/restoring the ITS state before the guest writes the ITS registers (on first boot or after reset/reboot). This is a follow up of Wanghaibin's series [1] plus additional patches following additional code review. It also proposes one ITS reset implementation. Currently, the in-kernel emulated ITS is not reset. After a reset/reboot, the ITS register values and caches are left unchanged. Registers may point to some tables in guest memory which do not exist anymore. If an ITS state backup is initiated before the guest re-writes the registers, the save fails because inconsistencies are detected. Also restore of data saved as such moment is failing. Patches [1-7] attempt to fix the migration issues without implementing the reset. As such they may be candidate for stable: - handle case where all collection, device and ITT entries are invalid on restore (which shouldn't be an error) - limit the cases where we return -EINVAL in table save() - never attempt to use GITS_BASER<n> and GITS_CBASER if they are not valid. - Check GITS_BASER<n> and GITS_CBASER on ITS enable - systematically do both device and collection save/restore even if one fails. Patches [8-11] implement a new ITS reset IOCTL Best Regards Eric Git: complete series available at https://github.com/eauger/linux/tree/v4.14-rc5-its-reset-v3 * Testing: - on Cavium using a virtio-net-pci guest and various sequences of guest shutdown -r now, virsh reset, virsh suspend/resume, virsh reboot, virsh save.restore, virsh shutdown References: [1] [RFC PATCH 0/3] fix migrate failed when vm is in booting https://www.spinics.net/lists/kvm-arm/msg27121.html History: v2 -> v3: - Revisited error handling in restore functions - Added "KVM: arm/arm64: vgic-its: fix vgic_its_restore_collection_table returned value" - Added "KVM: arm/arm64: vgic-its: Check CBASER/BASER validity before enabling the ITS" - Removed KVM: arm/arm64: vgic-its: Always allow clearing GITS_CREADR/CWRITER - Reworded documentation according to Christoffer's comments v1 -> v2: - added KVM: arm/arm64: vgic-its: Always attempt to save/restore device and collection tables PATCH v1 - series including 2 modified patches of Wanghaibin Eric Auger (10): KVM: arm/arm64: vgic-its: fix return value for device table restore KVM: arm/arm64: vgic-its: fix vgic_its_restore_collection_table returned value KVM: arm/arm64: vgic-its: Improve error reporting on device table save KVM: arm/arm64: vgic-its: Check CBASER/BASER validity before enabling the ITS KVM: arm/arm64: vgic-its: Check GITS_BASER Valid bit before saving tables KVM: arm/arm64: vgic-its: Check GITS_CBASER validity before processing commands KVM: arm/arm64: vgic-its: Always attempt to save/restore device and collection tables KVM: arm/arm64: vgic-its: free caches when GITS_BASER Valid bit is cleared KVM: arm/arm64: Document KVM_DEV_ARM_ITS_CTRL_RESET KVM: arm/arm64: vgic-its: Implement KVM_DEV_ARM_ITS_CTRL_RESET wanghaibin (1): KVM: arm/arm64: vgic-its: new helper functions to free the caches Documentation/virtual/kvm/devices/arm-vgic-its.txt | 20 ++ arch/arm/include/uapi/asm/kvm.h | 1 + arch/arm64/include/uapi/asm/kvm.h | 1 + virt/kvm/arm/vgic/vgic-its.c | 357 ++++++++++++++------- 4 files changed, 267 insertions(+), 112 deletions(-) -- 2.5.5
