This series implements support for allowing KVM guests to use the Arm Scalable Vector Extension (SVE). The patches are also available on a branch for reviewer convenience. [1] The patches are based on v4.20-rc5, with [3] applied (which includes some needed refactoring). This is an interim posting of rework of the previous preliminary series [2], addressing mostly minor comments, plus one significant change outlined below which is likely to require discussion -- I'm posting this series now so that people can comment while I try to work out how best to improve it. In the interest of getting this series out for review, this series remains untested. For description of minor updates, see the individual patches. Major changes: * Due to sequencing problems between KVM_ARM_VCPU_INIT / KVM_ARM_SVE_CONFIG / KVM_ARM_GET_REG_LIST, I have attempted to add some enforcement to the order in which ioctls are issued. This enforcement is applied on a opt-in basis, enabled by userspace specifying the KVM_VM_TYPE_ARM_SVE flag in KVM_CREATE_VM. This makes is possible to enforce SVE configuration to happen before (and only before) KVM_VCPU_INIT is called. **Discussion required** I'm now doubtful about the resulting model, because: * Calling kvm_vcpu_set_target() (via KVM_VCPU_INIT) _after_ setting the vcpu's vector lengths "feels wrong". Surely selecting the target CPU would determine the set of vector lengths (or at least establish a default set which might subsequently be customised by the caller)? * The main issue with KVM_VCPU_INIT seems to be that it selects the target vcpu and resets it in a single call, providing no opportunity to configure the vcpu further before it gets reset and is marked ready to run. This oddity is also highlighted by the fact that further KVM_VCPU_INIT calls are not allowed to reconfigure the vcpu, but reset it instead; so KVM_VCPU_INIT is actually welding together two different actions. Perhaps it would be better to select a modified KVM_VCPU_INIT behaviour via a feature flag in kvm_vcpu_init.features, that makes KVM_VCPU_INIT return something like -EINPROGRESS after kvm_vcpu_set_target(). Then, supplementary config could be done via KVM_ARM_SVE_CONFIG etc. We could add a dedicated KVM_VCPU_RESET call to finalise the vcpu configuration (if unfinalised) and reset it. I haven't tried this model out yet, but I'd be interested in people's views on it. Alternatively, there may be other better ways to crowbar the SVE setup into the vcpu creation/initialisation sequence. We want something that can be reused without needing to be reinvented yet again to support another feature... Known issues: * kvmtool/qemu updates are needed to enable creation of SVE-enabled guests (to be discussed separately). * Build-tested only. [1] http://linux-arm.org/git?p=linux-dm.git;a=shortlog;h=refs/heads/sve-kvm/rfcv3 git://linux-arm.org/linux-dm.git sve-kvm/rfcv3 [2] [RFC PATCH v2 00/23] KVM: arm64: Initial support for SVE guests http://lists.infradead.org/pipermail/linux-arm-kernel/2018-September/604550.html [3] [PATCH 0/3] Fix KVM_GET_REG_LIST invalid register ID regression https://lists.cs.columbia.edu/pipermail/kvmarm/2018-December/033710.html Dave Martin (24): 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 arm64/sve: Check SVE virtualisability arm64/sve: Clarify role of the VQ map maintenance functions arm64/sve: Enable SVE state tracking for non-task contexts KVM: arm64: Add a vcpu flag to control SVE visibility for the guest KVM: arm64: Propagate vcpu into read_id_reg() KVM: arm64: Extend reset_unknown() to handle mixed RES0/UNKNOWN registers KVM: arm64: Support runtime sysreg filtering for KVM_GET_REG_LIST 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 ioctl interface KVM: arm64: Reject ioctl access to FPSIMD V-regs on SVE vcpus KVM: arm64/sve: Add SVE support to register access ioctl interface KVM: arm64: Enumerate SVE register indices for KVM_GET_REG_LIST arm64/sve: In-kernel vector length availability query interface KVM: arm: Move detection of invalid VM type bits to generic code KVM: arm: Add support for early vcpu configuration ioctls KVM: arm64/sve: Report and enable SVE API extensions for userspace KVM: arm64/sve: allow KVM_ARM_SVE_CONFIG_QUERY on vm fd KVM: Documentation: Document arm64 core registers in detail KVM: arm64/sve: Document KVM API extensions for SVE Documentation/virtual/kvm/api.txt | 194 +++++++++++++++++++ arch/arm/include/asm/kvm_host.h | 21 +- arch/arm/include/uapi/asm/kvm.h | 3 + arch/arm64/include/asm/fpsimd.h | 33 +++- arch/arm64/include/asm/kvm_host.h | 40 +++- arch/arm64/include/asm/kvm_hyp.h | 1 - arch/arm64/include/asm/sysreg.h | 3 + arch/arm64/include/uapi/asm/kvm.h | 24 +++ arch/arm64/kernel/cpufeature.c | 2 +- arch/arm64/kernel/fpsimd.c | 172 ++++++++++++----- arch/arm64/kernel/signal.c | 5 - arch/arm64/kvm/fpsimd.c | 15 +- arch/arm64/kvm/guest.c | 396 +++++++++++++++++++++++++++++++++++--- arch/arm64/kvm/hyp/switch.c | 70 +++++-- arch/arm64/kvm/reset.c | 69 ++++++- arch/arm64/kvm/sys_regs.c | 144 ++++++++++++-- arch/arm64/kvm/sys_regs.h | 15 +- include/uapi/linux/kvm.h | 14 ++ virt/kvm/arm/arm.c | 16 +- 19 files changed, 1107 insertions(+), 130 deletions(-) -- 2.1.4 _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
