From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [RFC PATCH 1/2] Hyper-H reference counter Date: Thu, 16 May 2013 16:40:08 +0200 Message-ID: <5194EFC8.8070102@redhat.com> References: <1368445517-5496-1-git-send-email-vrozenfe@redhat.com> <1368445517-5496-2-git-send-email-vrozenfe@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, gleb@redhat.com, mtosatti@redhat.com, pl@dlh.net To: Vadim Rozenfeld Return-path: Received: from mail-gg0-f180.google.com ([209.85.161.180]:43432 "EHLO mail-gg0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751167Ab3EPOkU (ORCPT ); Thu, 16 May 2013 10:40:20 -0400 Received: by mail-gg0-f180.google.com with SMTP id q4so604668ggn.39 for ; Thu, 16 May 2013 07:40:19 -0700 (PDT) In-Reply-To: <1368445517-5496-2-git-send-email-vrozenfe@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Il 13/05/2013 13:45, Vadim Rozenfeld ha scritto: > Signed-off: Peter Lieven > Signed-off: Gleb Natapov > Signed-off: Vadim Rozenfeld > > The following patch allows to activate Hyper-V > reference time counter > --- > arch/x86/include/asm/kvm_host.h | 2 ++ > arch/x86/include/uapi/asm/hyperv.h | 3 +++ > arch/x86/kvm/x86.c | 25 ++++++++++++++++++++++++- > 3 files changed, 29 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 3741c65..f0fee35 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -575,6 +575,8 @@ struct kvm_arch { > /* fields used by HYPER-V emulation */ > u64 hv_guest_os_id; > u64 hv_hypercall; > + u64 hv_ref_count; > + u64 hv_tsc_page; > > #ifdef CONFIG_KVM_MMU_AUDIT > int audit_point; > diff --git a/arch/x86/include/uapi/asm/hyperv.h b/arch/x86/include/uapi/asm/hyperv.h > index b80420b..9711819 100644 > --- a/arch/x86/include/uapi/asm/hyperv.h > +++ b/arch/x86/include/uapi/asm/hyperv.h > @@ -136,6 +136,9 @@ > /* MSR used to read the per-partition time reference counter */ > #define HV_X64_MSR_TIME_REF_COUNT 0x40000020 > > +/* A partition's reference time stamp counter (TSC) page */ > +#define HV_X64_MSR_REFERENCE_TSC 0x40000021 > + > /* Define the virtual APIC registers */ > #define HV_X64_MSR_EOI 0x40000070 > #define HV_X64_MSR_ICR 0x40000071 > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 094b5d9..1a4036d 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -843,7 +843,7 @@ EXPORT_SYMBOL_GPL(kvm_rdpmc); > static u32 msrs_to_save[] = { > MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK, > MSR_KVM_SYSTEM_TIME_NEW, MSR_KVM_WALL_CLOCK_NEW, > - HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL, > + HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL,HV_X64_MSR_TIME_REF_COUNT, > HV_X64_MSR_APIC_ASSIST_PAGE, MSR_KVM_ASYNC_PF_EN, MSR_KVM_STEAL_TIME, > MSR_KVM_PV_EOI_EN, > MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP, > @@ -1764,6 +1764,8 @@ static bool kvm_hv_msr_partition_wide(u32 msr) > switch (msr) { > case HV_X64_MSR_GUEST_OS_ID: > case HV_X64_MSR_HYPERCALL: > + case HV_X64_MSR_REFERENCE_TSC: > + case HV_X64_MSR_TIME_REF_COUNT: > r = true; > break; > } > @@ -1803,6 +1805,21 @@ static int set_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data) > if (__copy_to_user((void __user *)addr, instructions, 4)) > return 1; > kvm->arch.hv_hypercall = data; > + kvm->arch.hv_ref_count = get_kernel_ns(); > + break; > + } > + case HV_X64_MSR_REFERENCE_TSC: { > + u64 gfn; > + unsigned long addr; > + u32 tsc_ref; > + gfn = data >> HV_X64_MSR_HYPERCALL_PAGE_ADDRESS_SHIFT; > + addr = gfn_to_hva(kvm, gfn); > + if (kvm_is_error_hva(addr)) > + return 1; > + tsc_ref = 0; > + if(__copy_to_user((void __user *)addr, &tsc_ref, sizeof(tsc_ref))) > + return 1; > + kvm->arch.hv_tsc_page = data; > break; > } > default: > @@ -2229,6 +2246,12 @@ static int get_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata) > case HV_X64_MSR_HYPERCALL: > data = kvm->arch.hv_hypercall; > break; > + case HV_X64_MSR_TIME_REF_COUNT: > + data = div_u64(get_kernel_ns() - kvm->arch.hv_ref_count,100); > + break; For migration, this should probably be writable from userspace (msr_info->host_initiated in kvm_set_msr_common). However, the spec says that the reference counter must count up from 0 _when the partition is created_, not when you initialize the enlightenments. Perhaps we can just piggy back on the kvmclock ioctls and remove hv_ref_count altogether. Then userspace doesn't need to write to HV_X64_MSR_TIME_REF_COUNT. Paolo > + case HV_X64_MSR_REFERENCE_TSC: > + data = kvm->arch.hv_tsc_page; > + break; > default: > vcpu_unimpl(vcpu, "Hyper-V unhandled rdmsr: 0x%x\n", msr); > return 1; >