Il 17/01/2014 14:18, Marcelo Tosatti ha scritto: > On Fri, Jan 17, 2014 at 10:06:00PM +1100, Vadim Rozenfeld wrote: >> On Thu, 2014-01-16 at 20:23 -0200, Marcelo Tosatti wrote: >>> On Thu, Jan 16, 2014 at 08:18:37PM +1100, Vadim Rozenfeld wrote: >>>> Signed-off: Peter Lieven <pl@xxxxxxx> >>>> Signed-off: Gleb Natapov >>>> Signed-off: Vadim Rozenfeld <vrozenfe@xxxxxxxxxx> >>>> >>>> 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. >>>> >>>> v1 -> v2 >>>> 1. mark TSC page dirty as suggested by >>>> Eric Northup <digitaleric@xxxxxxxxxx> and Gleb >>>> 2. disable local irq when calling get_kernel_ns, >>>> as it was done by Peter Lieven <pl@xxxxxx> >>>> 3. move check for TSC page enable from second patch >>>> to this one. >>>> >>>> v3 -> v4 >>>> Get rid of ref counter offset. >>>> >>>> v4 -> v5 >>>> replace __copy_to_user with kvm_write_guest >>>> when updateing iTSC page. >>>> >>>> --- >>>> 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(-) >>>> >>>> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_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; >>>> >>>> #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 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) >>>> >>>> +/* 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)) >>>> >>>> +#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 >>>> >>>> +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. >>>> */ >>>> >>>> -#define KVM_SAVE_MSRS_BEGIN 10 >>>> +#define KVM_SAVE_MSRS_BEGIN 12 >>>> 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_TIME_REF_COUNT, HV_X64_MSR_REFERENCE_TSC, >>>> 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, >>>> @@ -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 = true; >>>> break; >>>> } >>>> @@ -1867,6 +1870,20 @@ static int set_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data) >>>> kvm->arch.hv_hypercall = 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 = 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? >> >> Windows seems to be retrieving HV_X64_MSR_REFERENCE_TSC value only once >> on boot-up, checks HV_X64_MSR_TSC_REFERENCE_ENABLE bit allocate one page >> and maps it into the system space, and writes the page address to >> HV_X64_MSR_REFERENCE_TSC MSR if this bit was not set. Windows keeps the >> TSC page address value in HvlReferenceTscPage variable and uses it >> every time when needs to read the TSC page content. > > Ok then it has to be saved/restored irrespective of the value of > HV_X64_MSR_TSC_REFERENCE_ENABLE. > >>> If not, should only assign to kvm->arch.hv_tsc_page after proper checks. >>> >>>> + if (!(data & HV_X64_MSR_TSC_REFERENCE_ENABLE)) >>>> + break; >>>> + gfn = 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 = kvm->arch.hv_hypercall; >>>> break; >>>> + case HV_X64_MSR_TIME_REF_COUNT: { >>>> + data = >>>> + 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 ? >> >> The MS documentation says the following: >> "A partition's reference time counter is initialized to zero when the >> partition is created. The reference time counter for all partitions >> count at the same rate. However, at any time, the absolute value of each >> reference time counter will typically differ because partitions will >> have different creation times." >> >> http://msdn.microsoft.com/en-us/library/windows/hardware/ff542637% >> 28v=vs.85%29.aspx >> >> However, Windows doesn't seem to be worried about the initial value. >> HvlGetReferenceTime only reads HV_X64_MSR_TIME_REF_COUNT MSR and >> returns the obtained value. > > Right. It might be better to initialize kvmclock_offset to zero > in case of VM creation (QEMU's PUT_FULL state), in case Hyper-V timers > enabled, with reference to MS docs on top. > > Otherwise might end up hitting Windows code timers bugs. > > But its a potential improvement, patch looks good. > >>>> + } >>>> + 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; >>>> @@ -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 = 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 >>>> >>>> #ifdef KVM_CAP_IRQ_ROUTING >>>> >>>> -- >>>> 1.8.1.4 >>>> >>> >>> Comment 3) >>> >>> Missing qemu HV_X64_MSR_REFERENCE_TSC save/restore. >> I have this code ready. I'm going to send it to qemu >> list as soon as KVM patch will be accepted. > > Looks good to me. > Applied to kvm/queue, thanks! Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html