From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: Re: [RFC PATCH v5] add support for Hyper-V reference time counter Date: Thu, 16 Jan 2014 20:23:00 -0200 Message-ID: <20140116222259.GA15335@amt.cnet> References: <1389863917-18558-1-git-send-email-vrozenfe@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: kvm@vger.kernel.org, pbonzini@redhat.com, pl@dlhnet.de To: Vadim Rozenfeld Return-path: Received: from mx1.redhat.com ([209.132.183.28]:9891 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750750AbaAPWYU (ORCPT ); Thu, 16 Jan 2014 17:24:20 -0500 Content-Disposition: inline In-Reply-To: <1389863917-18558-1-git-send-email-vrozenfe@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Thu, Jan 16, 2014 at 08:18:37PM +1100, Vadim Rozenfeld wrote: > Signed-off: Peter Lieven > Signed-off: Gleb Natapov > Signed-off: Vadim Rozenfeld > =20 > After some consideration I decided to submit only Hyper-V reference > counters support this time. I will submit iTSC support as a separate > patch as soon as it is ready.=20 >=20 > v1 -> v2 > 1. mark TSC page dirty as suggested by=20 > Eric Northup and Gleb > 2. disable local irq when calling get_kernel_ns,=20 > as it was done by Peter Lieven > 3. move check for TSC page enable from second patch > to this one. >=20 > v3 -> v4 > =A0=A0=A0=A0Get rid of ref counter offset. >=20 > v4 -> v5 > replace __copy_to_user with kvm_write_guest > when updateing iTSC page. >=20 > --- > arch/x86/include/asm/kvm_host.h | 1 + > arch/x86/include/uapi/asm/hyperv.h | 13 +++++++++++++ > arch/x86/kvm/x86.c | 28 +++++++++++++++++++++++++++- > include/uapi/linux/kvm.h | 1 + > 4 files changed, 42 insertions(+), 1 deletion(-) >=20 > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/k= vm_host.h > index ae5d783..33fef07 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -605,6 +605,7 @@ struct kvm_arch { > /* fields used by HYPER-V emulation */ > u64 hv_guest_os_id; > u64 hv_hypercall; > + u64 hv_tsc_page; > =20 > #ifdef CONFIG_KVM_MMU_AUDIT > int audit_point; > diff --git a/arch/x86/include/uapi/asm/hyperv.h b/arch/x86/include/ua= pi/asm/hyperv.h > index b8f1c01..462efe7 100644 > --- a/arch/x86/include/uapi/asm/hyperv.h > +++ b/arch/x86/include/uapi/asm/hyperv.h > @@ -28,6 +28,9 @@ > /* Partition Reference Counter (HV_X64_MSR_TIME_REF_COUNT) available= */ > #define HV_X64_MSR_TIME_REF_COUNT_AVAILABLE (1 << 1) > =20 > +/* A partition's reference time stamp counter (TSC) page */ > +#define HV_X64_MSR_REFERENCE_TSC 0x40000021 > + > /* > * There is a single feature flag that signifies the presence of the= MSR > * that can be used to retrieve both the local APIC Timer frequency = as > @@ -198,6 +201,9 @@ > #define HV_X64_MSR_APIC_ASSIST_PAGE_ADDRESS_MASK \ > (~((1ull << HV_X64_MSR_APIC_ASSIST_PAGE_ADDRESS_SHIFT) - 1)) > =20 > +#define HV_X64_MSR_TSC_REFERENCE_ENABLE 0x00000001 > +#define HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT 12 > + > #define HV_PROCESSOR_POWER_STATE_C0 0 > #define HV_PROCESSOR_POWER_STATE_C1 1 > #define HV_PROCESSOR_POWER_STATE_C2 2 > @@ -210,4 +216,11 @@ > #define HV_STATUS_INVALID_ALIGNMENT 4 > #define HV_STATUS_INSUFFICIENT_BUFFERS 19 > =20 > +typedef struct _HV_REFERENCE_TSC_PAGE { > + __u32 tsc_sequence; > + __u32 res1; > + __u64 tsc_scale; > + __s64 tsc_offset; > +} HV_REFERENCE_TSC_PAGE, *PHV_REFERENCE_TSC_PAGE; > + > #endif > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 5d004da..8e685b8 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -836,11 +836,12 @@ EXPORT_SYMBOL_GPL(kvm_rdpmc); > * kvm-specific. Those are put in the beginning of the list. > */ > =20 > -#define KVM_SAVE_MSRS_BEGIN 10 > +#define KVM_SAVE_MSRS_BEGIN 12 > static u32 msrs_to_save[] =3D { > 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_TIME_REF_COUNT, HV_X64_MSR_REFERENCE_TSC, > HV_X64_MSR_APIC_ASSIST_PAGE, MSR_KVM_ASYNC_PF_EN, MSR_KVM_STEAL_TIM= E, > MSR_KVM_PV_EOI_EN, > MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP, > @@ -1826,6 +1827,8 @@ 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 =3D true; > break; > } > @@ -1867,6 +1870,20 @@ static int set_msr_hyperv_pw(struct kvm_vcpu *= vcpu, u32 msr, u64 data) > kvm->arch.hv_hypercall =3D data; > break; > } > + case HV_X64_MSR_REFERENCE_TSC: { > + u64 gfn; > + HV_REFERENCE_TSC_PAGE tsc_ref; > + memset(&tsc_ref, 0, sizeof(tsc_ref)); > + kvm->arch.hv_tsc_page =3D data; Comment 1) Is there a reason (that is compliance with spec) to maintain value, for HV_X64_MSR_REFERENCE_TSC wrmsr operation, in case HV_X64_MSR_TSC_REFERENCE_ENABLE is not set? If not, should only assign to kvm->arch.hv_tsc_page after proper checks= =2E > + if (!(data & HV_X64_MSR_TSC_REFERENCE_ENABLE)) > + break; > + gfn =3D data >> HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT; > + if (kvm_write_guest(kvm, data, > + &tsc_ref, sizeof(tsc_ref))) > + return 1; > + mark_page_dirty(kvm, gfn); > + break; > + } > default: > vcpu_unimpl(vcpu, "HYPER-V unimplemented wrmsr: 0x%x " > "data 0x%llx\n", msr, data); > @@ -2291,6 +2308,14 @@ static int get_msr_hyperv_pw(struct kvm_vcpu *= vcpu, u32 msr, u64 *pdata) > case HV_X64_MSR_HYPERCALL: > data =3D kvm->arch.hv_hypercall; > break; > + case HV_X64_MSR_TIME_REF_COUNT: { > + data =3D > + div_u64(get_kernel_ns() + kvm->arch.kvmclock_offset, 100); Comment 2) Is there any specification related to the initial value of the clock after it is enabled ? > + break; > + } > + case HV_X64_MSR_REFERENCE_TSC: > + data =3D kvm->arch.hv_tsc_page; > + break; > default: > vcpu_unimpl(vcpu, "Hyper-V unhandled rdmsr: 0x%x\n", msr); > return 1; > @@ -2604,6 +2629,7 @@ int kvm_dev_ioctl_check_extension(long ext) > #ifdef CONFIG_KVM_DEVICE_ASSIGNMENT > case KVM_CAP_ASSIGN_DEV_IRQ: > case KVM_CAP_PCI_2_3: > + case KVM_CAP_HYPERV_TIME: > #endif > r =3D 1; > break; > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > index 902f124..686c1ca 100644 > --- a/include/uapi/linux/kvm.h > +++ b/include/uapi/linux/kvm.h > @@ -674,6 +674,7 @@ struct kvm_ppc_smmu_info { > #define KVM_CAP_ARM_EL1_32BIT 93 > #define KVM_CAP_SPAPR_MULTITCE 94 > #define KVM_CAP_EXT_EMUL_CPUID 95 > +#define KVM_CAP_HYPERV_TIME 96 > =20 > #ifdef KVM_CAP_IRQ_ROUTING > =20 > --=20 > 1.8.1.4 >=20 Comment 3)=20 Missing qemu HV_X64_MSR_REFERENCE_TSC save/restore. No further comments.