This series aims at satisfying multiple goals: - allow a VMM to atomically restore a timer offset for a whole VM instead of updating the offset each time a vcpu get its counter written - allow a VMM to save/restore the physical timer context, something that we cannot do at the moment due to the lack of offsetting - provide a framework that is suitable for NV support, where we get both global and per timer, per vcpu offsetting We fix a couple of issues along the way, both from a stylistic and correctness perspective. This results in a new per VM KVM API that allows a pair of global offsets to be set at any point in time, overriding the timer counter writeback. This has been moderately tested with nVHE, VHE and NV. I do not have access to CNTPOFF-aware HW, so the jury is still out on that one. Note that the NV patches in this series are here to give a perspective on how this gets used. I've updated the arch_timer selftest to allow offsets to be provided from the command line, but the arch_test is pretty flimsy and tends to fail with an error==EINTR, even without this series. Something to investigate. Note that this is at best 6.4 material. I have a branch stashed at [1] and based on kvmarm/next. Thanks, M. [1] https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/log/?h=kvm-arm64/timer-vm-offsets Marc Zyngier (16): arm64: Add CNTPOFF_EL2 register definition arm64: Add HAS_ECV_CNTPOFF capability kvm: arm64: Expose {un,}lock_all_vcpus() to the reset of KVM KVM: arm64: timers: Use a per-vcpu, per-timer accumulator for fractional ns KVM: arm64: timers: Convert per-vcpu virtual offset to a global value KVM: arm64: timers: Use CNTPOFF_EL2 to offset the physical timer KVM: arm64: timers: Allow physical offset without CNTPOFF_EL2 KVM: arm64: timers: Allow userspace to set the counter offsets KVM: arm64: timers: Allow save/restoring of the physical timer KVM: arm64: timers: Rationalise per-vcpu timer init KVM: arm64: Document KVM_ARM_SET_CNT_OFFSETS and co KVM: arm64: nv: timers: Add a per-timer, per-vcpu offset KVM: arm64: nv: timers: Support hyp timer emulation KVM: arm64: selftests: Add physical timer registers to the sysreg list KVM: arm64: selftests: Augment existing timer test to handle variable offsets KVM: arm64: selftests: Deal with spurious timer interrupts Documentation/virt/kvm/api.rst | 47 ++ arch/arm64/include/asm/kvm_host.h | 14 + arch/arm64/include/uapi/asm/kvm.h | 15 + arch/arm64/kernel/cpufeature.c | 11 + arch/arm64/kvm/arch_timer.c | 443 ++++++++++++++---- arch/arm64/kvm/arm.c | 47 ++ arch/arm64/kvm/guest.c | 29 +- arch/arm64/kvm/hyp/nvhe/timer-sr.c | 18 +- arch/arm64/kvm/hypercalls.c | 2 +- arch/arm64/kvm/trace_arm.h | 6 +- arch/arm64/kvm/vgic/vgic-kvm-device.c | 38 -- arch/arm64/kvm/vgic/vgic.c | 15 + arch/arm64/kvm/vgic/vgic.h | 3 - arch/arm64/tools/cpucaps | 1 + arch/arm64/tools/sysreg | 4 + include/clocksource/arm_arch_timer.h | 1 + include/kvm/arm_arch_timer.h | 32 +- include/kvm/arm_vgic.h | 1 + include/uapi/linux/kvm.h | 3 + .../selftests/kvm/aarch64/arch_timer.c | 26 +- .../selftests/kvm/aarch64/get-reg-list.c | 5 +- 21 files changed, 603 insertions(+), 158 deletions(-) -- 2.34.1
