On 19/07/19 08:31, Tao Xu wrote: > Ping for comments :) Hi, I'll look at it for 5.4, right after the merge window. Paolo > On 7/16/2019 2:55 PM, Tao Xu wrote: >> UMONITOR, UMWAIT and TPAUSE are a set of user wait instructions. >> >> UMONITOR arms address monitoring hardware using an address. A store >> to an address within the specified address range triggers the >> monitoring hardware to wake up the processor waiting in umwait. >> >> UMWAIT instructs the processor to enter an implementation-dependent >> optimized state while monitoring a range of addresses. The optimized >> state may be either a light-weight power/performance optimized state >> (c0.1 state) or an improved power/performance optimized state >> (c0.2 state). >> >> TPAUSE instructs the processor to enter an implementation-dependent >> optimized state c0.1 or c0.2 state and wake up when time-stamp counter >> reaches specified timeout. >> >> Availability of the user wait instructions is indicated by the presence >> of the CPUID feature flag WAITPKG CPUID.0x07.0x0:ECX[5]. >> >> The patches enable the umonitor, umwait and tpause features in KVM. >> Because umwait and tpause can put a (psysical) CPU into a power saving >> state, by default we dont't expose it to kvm and enable it only when >> guest CPUID has it. If the instruction causes a delay, the amount >> of time delayed is called here the physical delay. The physical delay is >> first computed by determining the virtual delay (the time to delay >> relative to the VM’s timestamp counter). >> >> The release document ref below link: >> Intel 64 and IA-32 Architectures Software Developer's Manual, >> https://software.intel.com/sites/default/files/\ >> managed/39/c5/325462-sdm-vol-1-2abcd-3abcd.pdf >> >> Changelog: >> v8: >> Add vmx_waitpkg_supported() helper (Sean) >> Add an accessor to expose umwait_control_cached (Sean) >> Set msr_ia32_umwait_control in vcpu_vmx u32 and raise #GP when >> [63:32] is set when rdmsr. (Sean) >> Introduce a common exit helper handle_unexpected_vmexit (Sean) >> v7: >> Add nested support for user wait instructions (Paolo) >> Use the test on vmx->secondary_exec_control to replace >> guest_cpuid_has (Paolo) >> v6: >> add check msr_info->host_initiated in get/set msr(Xiaoyao) >> restore the atomic_switch_umwait_control_msr()(Xiaoyao) >> >> Tao Xu (3): >> KVM: x86: Add support for user wait instructions >> KVM: vmx: Emulate MSR IA32_UMWAIT_CONTROL >> KVM: vmx: Introduce handle_unexpected_vmexit and handle WAITPKG vmexit >> >> arch/x86/include/asm/vmx.h | 1 + >> arch/x86/include/uapi/asm/vmx.h | 6 ++- >> arch/x86/kernel/cpu/umwait.c | 6 +++ >> arch/x86/kvm/cpuid.c | 2 +- >> arch/x86/kvm/vmx/capabilities.h | 6 +++ >> arch/x86/kvm/vmx/nested.c | 5 ++ >> arch/x86/kvm/vmx/vmx.c | 83 ++++++++++++++++++++++++++------- >> arch/x86/kvm/vmx/vmx.h | 9 ++++ >> arch/x86/kvm/x86.c | 1 + >> 9 files changed, 101 insertions(+), 18 deletions(-) >> >
