The ARMv8.7 WFxT feature is a new take on the good old WFI/WFE instructions as they behave the same way, only taking an extra timeout parameter. This small series aims at adding the minimal support for this feature, enabling it for both the kernel and KVM. A potential addition to this series would be to remove the event generation from the counters, and rely on the timeout where it matters (spinlocks?). Feedback welcome. Patches on top of 5.18-rc2, tested of the FVP AEM. Marc Zyngier (10): arm64: Expand ESR_ELx_WFx_ISS_TI to match its ARMv8.7 definition arm64: Add RV and RN fields for ESR_ELx_WFx_ISS KVM: arm64: Simplify kvm_cpu_has_pending_timer() KVM: arm64: Introduce kvm_counter_compute_delta() helper KVM: arm64: Handle blocking WFIT instruction KVM: arm64: Offer early resume for non-blocking WFxT instructions KVM: arm64: Expose the WFXT feature to guests arm64: Add HWCAP advertising FEAT_WFXT arm64: Add wfet()/wfit() helpers arm64: Use WFxT for __delay() when possible Documentation/arm64/cpu-feature-registers.rst | 2 + Documentation/arm64/elf_hwcaps.rst | 4 ++ arch/arm64/include/asm/barrier.h | 4 ++ arch/arm64/include/asm/esr.h | 8 +++- arch/arm64/include/asm/hwcap.h | 1 + arch/arm64/include/asm/kvm_host.h | 1 + arch/arm64/include/uapi/asm/hwcap.h | 1 + arch/arm64/kernel/cpufeature.c | 13 +++++ arch/arm64/kernel/cpuinfo.c | 1 + arch/arm64/kvm/arch_timer.c | 47 ++++++++++++------- arch/arm64/kvm/arm.c | 6 +-- arch/arm64/kvm/handle_exit.c | 30 ++++++++++-- arch/arm64/kvm/sys_regs.c | 2 + arch/arm64/lib/delay.c | 12 ++++- arch/arm64/tools/cpucaps | 1 + include/kvm/arm_arch_timer.h | 2 - 16 files changed, 106 insertions(+), 29 deletions(-) -- 2.34.1
