This series implements support for allowing KVM guests to use the Arm Scalable Vector Extension (SVE), superseding the previous v4 series [1]. The patches are also available on a branch for reviewer convenience. [2] The patches are based on v5.0-rc6. They depend on another small series currently under review [3] that does a bit of relevant refactoring (as well as fixing an anomaly not directly related to this series). A base branch [4] is provided so that reviewers don't need to hunt down both series independently. This series contains no major update except for the removal of multiple register slice support in the user register access ioctls. The ABI is kept as-is so that this functionality can be added back in later on if/when needed. ioctl access to nonexistent slices now yields ENOENT, which is more consistent with the notion of an absent register. For a description of minor updates, see the individual patches. Functionality testing and stress-testing has been done, using a hacked-up kvmtool [5]: * Arm Fast Model: full testing of arm64 defconfig, including running non-SVE and SVE guests with mixtures of vector lengths. limited testing of other configurations. * ThunderX2: basic testing of arm64 defconfig, including booting guests (no SVE support on this hardware). * Full build-bisect testing and sparse testing of every commit done for arm64 (defconfig, CONFIG_ARM64_SVE=n, CONFIG_KVM=n) and arm (multi_v7_defconfig, CONFIG_KVM=y). One new sparse warning, probably spurious (see note in patch 22). AArch32 host testing is pending. I will ping this series with a reply to the cover letter when that testing has been completed. Known issues: * **Possible bug** SVE state corruption has been in the host when running on the Arm Fast Model. After some investigation with the model engineers, it appears that there may be a model bug in this area. I have also obtained detailed trace of failure cases, which is also suggestive of a model bug. No clear evidence has been obtained to show that there is a bug in Linux, so far. All available evidence suggests that this bug will not affect non-SVE hardware: the symptom is unexpected zeroing of bits 128 and above of the vector registers (which don't exist prior to SVE). * kvmtool support is not mature [1] [RFC PATCH v4 00/24] KVM: arm64: SVE guest support https://lists.cs.columbia.edu/pipermail/kvmarm/2019-January/034134.html [2] This series in git: http://linux-arm.org/git?p=linux-dm.git;a=shortlog;h=refs/heads/sve-kvm/v5/head git://linux-arm.org/linux-dm.git sve-kvm/v5/head [3] [PATCH v2 0/2] Fix KVM_GET_REG_LIST invalid register ID regression https://lists.cs.columbia.edu/pipermail/kvmarm/2018-December/033810.html [4] Base of this series in git: http://linux-arm.org/git?p=linux-dm.git;a=shortlog;h=refs/heads/sve-kvm/v5/base git://linux-arm.org/linux-dm.git sve-kvm/v5/base [5] [RFC PATCH 00/12] arm64: SVE guest support test hacks https://lists.cs.columbia.edu/pipermail/kvmarm/2019-January/034162.html Dave Martin (26): KVM: Documentation: Document arm64 core registers in detail 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 visibility filtering 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: Add missing #include of <linux/string.h> in guest.c 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/arm64: Add hook to finalize the vcpu configuration KVM: arm64/sve: Add pseudo-register for the guest's vector lengths KVM: arm64/sve: Allow userspace to enable SVE for vcpus KVM: arm64: Add a capabillity to advertise SVE support KVM: Document errors for KVM_GET_ONE_REG and KVM_SET_ONE_REG KVM: arm64/sve: Document KVM API extensions for SVE Documentation/virtual/kvm/api.txt | 93 ++++++++++ arch/arm/include/asm/kvm_host.h | 4 + arch/arm64/include/asm/fpsimd.h | 33 +++- arch/arm64/include/asm/kvm_host.h | 35 +++- arch/arm64/include/asm/kvm_hyp.h | 1 - arch/arm64/include/asm/sysreg.h | 3 + arch/arm64/include/uapi/asm/kvm.h | 22 +++ arch/arm64/kernel/cpufeature.c | 2 +- arch/arm64/kernel/fpsimd.c | 172 +++++++++++++------ arch/arm64/kernel/signal.c | 5 - arch/arm64/kvm/fpsimd.c | 17 +- arch/arm64/kvm/guest.c | 348 +++++++++++++++++++++++++++++++++++--- arch/arm64/kvm/hyp/switch.c | 69 ++++++-- arch/arm64/kvm/reset.c | 87 +++++++++- arch/arm64/kvm/sys_regs.c | 144 ++++++++++++++-- arch/arm64/kvm/sys_regs.h | 24 ++- include/uapi/linux/kvm.h | 2 + virt/kvm/arm/arm.c | 8 + 18 files changed, 944 insertions(+), 125 deletions(-) -- 2.1.4
