This series implements basic support for allowing KVM guests to use the Arm Scalable Vector Extension (SVE). The patches is based on torvalds/master f5b7769e (Revert "debugfs: inode: debugfs_create_dir uses mode permission from parent") plus the patches from [1]. Issues / missing features: * No way for userspace to determine or control the set of vector lengths exposed to the guest. This needs to be fixed for snapshotting/migration of guests to work reliably. An ioctl needs to be added for this (dropped from this series because I consider it lower-priority than the core support). * No documentation update yet (I'd like to get the interfaces finalised before I put too much effort into writing that...) * Patch 14 (SVE register ioctl() access core) may be too complicated in its handling of backwards compatibility for the FPSIMD regs: It might be simpler to use nvcpu->arch.ctxt.gp_regs.fp_regs.vregs[] as a bounce buffer rather than trying to redirect uaccess directly to the appropriate locations in vcpu->sve_state. I'd be interested in people's comments on this. * kvmtool/qemu updates are needed to enable creation of SVE-enabled guests (to be discussed separately). Brief notes on the patches: * Patches 1-4 are miscellaneous preliminary cleanups. * Patch 5 adds new arch vcpu init/teardown hooks due to the lack of an obvious place to free a vcpu's SVE state buffer. This may want a rethink, because the allocation part has now ended up in kvm_reset_vcpu() instead of the new init hook. * Patches 6-12 implement the core SVE support for guests (of which patch 8-9 refactor the sysregs code to support conditional hiding of the SVE-related registers). * Patches 13-15 implement ioctl() access for the new SVE registers. * Patch 16 exposes the new functionality to userspace, allowing SVE-enabled vcpus to be created. This series is somewhat tested on Arm Juno r0 and the Arm Fast Model (with/without SVE support). arch/arm builds, but I've not booted it -- only some trivial refactoring in this series affects arch/arm. Cheers ---Dave [1] [PATCH v2 0/4] KVM: arm64: FPSIMD/SVE fixes for 4.17 [sic] http://lists.infradead.org/pipermail/linux-arm-kernel/2018-June/584281.html Dave Martin (16): arm64: fpsimd: Always set TIF_FOREIGN_FPSTATE on task state flush KVM: arm64: Delete orphaned declaration for __fpsimd_enabled() KVM: arm64: Refactor kvm_arm_num_regs() for easier maintenance KVM: arm64: Add missing #include of <linux/bitmap.h> to kvm_host.h KVM: arm: Add arch init/uninit hooks arm64/sve: Determine virtualisation-friendly vector lengths arm64/sve: Enable SVE state tracking for non-task contexts KVM: arm64: Support dynamically hideable system registers KVM: arm64: Allow ID registers to by dynamically read-as-zero KVM: arm64: Add a vcpu flag to control SVE visibility for the guest KVM: arm64/sve: System register context switch and access support KVM: arm64/sve: Context switch the SVE registers KVM: Allow 2048-bit register access via KVM_{GET,SET}_ONE_REG KVM: arm64/sve: Add SVE support to register access ioctl interface KVM: arm64: Enumerate SVE register indices for KVM_GET_REG_LIST KVM: arm64/sve: Report and enable SVE API extensions for userspace arch/arm/include/asm/kvm_host.h | 4 +- arch/arm64/include/asm/fpsimd.h | 4 +- arch/arm64/include/asm/kvm_host.h | 18 ++- arch/arm64/include/asm/kvm_hyp.h | 1 - arch/arm64/include/asm/sysreg.h | 3 + arch/arm64/include/uapi/asm/kvm.h | 11 ++ arch/arm64/kernel/cpufeature.c | 2 +- arch/arm64/kernel/fpsimd.c | 131 +++++++++++++--- arch/arm64/kernel/signal.c | 5 - arch/arm64/kvm/fpsimd.c | 7 +- arch/arm64/kvm/guest.c | 321 +++++++++++++++++++++++++++++++++++--- arch/arm64/kvm/hyp/switch.c | 43 +++-- arch/arm64/kvm/hyp/sysreg-sr.c | 5 + arch/arm64/kvm/reset.c | 14 ++ arch/arm64/kvm/sys_regs.c | 73 ++++++--- arch/arm64/kvm/sys_regs.h | 22 +++ include/uapi/linux/kvm.h | 1 + virt/kvm/arm/arm.c | 13 +- 18 files changed, 587 insertions(+), 91 deletions(-) -- 2.1.4 _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
