This series adds support for using the Arm Memory Tagging Extensions (MTE) in a KVM guest. This time with less BKL but hopefully no new races! Changes since v15[1]: - Prevent VM_SHARED mappings with an MTE-enabled VM. - Dropped the mte_prepare_page_tags() function, sanitise_mte_tags() now does the PG_mte_tagged dance without extra locks. - Added a comment to sanitise_mte_tags() explaining why the apparent race with the test/set of page->flags is safe. - Added a sentence to kvm/api.rst explaining that VM_SHARED is not permitted when used with MTE in a guest. - Dropped the Reviewed-by tags on patches 3 and 7 due to the changes. [1] https://lore.kernel.org/r/20210614090525.4338-1-steven.price%40arm.com Steven Price (7): arm64: mte: Handle race when synchronising tags arm64: mte: Sync tags for pages where PTE is untagged KVM: arm64: Introduce MTE VM feature KVM: arm64: Save/restore MTE registers KVM: arm64: Expose KVM_ARM_CAP_MTE KVM: arm64: ioctl to fetch/store tags in a guest KVM: arm64: Document MTE capability and ioctl Documentation/virt/kvm/api.rst | 61 ++++++++++++++++ arch/arm64/include/asm/kvm_arm.h | 3 +- arch/arm64/include/asm/kvm_emulate.h | 3 + arch/arm64/include/asm/kvm_host.h | 12 ++++ arch/arm64/include/asm/kvm_mte.h | 66 +++++++++++++++++ arch/arm64/include/asm/mte-def.h | 1 + arch/arm64/include/asm/mte.h | 4 +- arch/arm64/include/asm/pgtable.h | 22 +++++- arch/arm64/include/asm/sysreg.h | 3 +- arch/arm64/include/uapi/asm/kvm.h | 11 +++ arch/arm64/kernel/asm-offsets.c | 2 + arch/arm64/kernel/mte.c | 37 ++++++++-- arch/arm64/kvm/arm.c | 16 +++++ arch/arm64/kvm/guest.c | 82 ++++++++++++++++++++++ arch/arm64/kvm/hyp/entry.S | 7 ++ arch/arm64/kvm/hyp/exception.c | 3 +- arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 21 ++++++ arch/arm64/kvm/mmu.c | 62 +++++++++++++++- arch/arm64/kvm/reset.c | 3 +- arch/arm64/kvm/sys_regs.c | 32 +++++++-- include/uapi/linux/kvm.h | 2 + 21 files changed, 432 insertions(+), 21 deletions(-) create mode 100644 arch/arm64/include/asm/kvm_mte.h -- 2.20.1 _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
