On Tue, May 21, 2013 at 09:46:14PM -0300, Marcelo Tosatti wrote: > On Sun, May 19, 2013 at 05:06:36PM +1000, Vadim Rozenfeld wrote: > > Signed-off: Peter Lieven <pl@xxxxxxx> > > Signed-off: Gleb Natapov <gleb@xxxxxxxxxx> > > Signed-off: Vadim Rozenfeld <vrozenfe@xxxxxxxxxx> > > > > 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@xxxxxxxxx> > > 3. move check for TSC page enable from second patch > > to this one. > > > > --- > > arch/x86/include/asm/kvm_host.h | 2 ++ > > arch/x86/include/uapi/asm/hyperv.h | 14 ++++++++++++++ > > arch/x86/kvm/x86.c | 39 +++++++++++++++++++++++++++++++++++++- > > include/uapi/linux/kvm.h | 1 + > > 4 files changed, 55 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..890dfc3 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 > > @@ -179,6 +182,9 @@ > > #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 > > @@ -191,4 +197,12 @@ > > #define HV_STATUS_INVALID_ALIGNMENT 4 > > #define HV_STATUS_INSUFFICIENT_BUFFERS 19 > > > > +typedef struct _HV_REFERENCE_TSC_PAGE { > > + __u32 TscSequence; > > + __u32 Rserved1; > > + __u64 TscScale; > > + __s64 TscOffset; > > +} HV_REFERENCE_TSC_PAGE, *PHV_REFERENCE_TSC_PAGE; > > + > > + > > #endif > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > index 8d28810..9645dab 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, not needed. > > - 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, > > @@ -1788,6 +1788,8 @@ 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; > > } > > @@ -1827,6 +1829,29 @@ 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; > > + local_irq_disable(); > > + kvm->arch.hv_ref_count = get_kernel_ns(); > > + local_irq_enable(); > > + break; > > local_irq_disable/local_irq_enable not needed. > get_kernel_ns has WARN_ON(preemptible()) so at least preempt_disable() is needed, but all callers of the function disable interrupts. > What is the reasoning behind reading this time value at msr write time? > > > + } > > + case HV_X64_MSR_REFERENCE_TSC: { > > + u64 gfn; > > + unsigned long addr; > > + HV_REFERENCE_TSC_PAGE tsc_ref; > > + tsc_ref.TscSequence = 0; > > + if (!(data & HV_X64_MSR_TSC_REFERENCE_ENABLE)) { > > + kvm->arch.hv_tsc_page = data; > > + break; > > + } > > + gfn = data >> HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT; > > + addr = gfn_to_hva(kvm, data >> > > + HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT); > > + if (kvm_is_error_hva(addr)) > > + return 1; > > + if (__copy_to_user((void __user *)addr, &tsc_ref, sizeof(tsc_ref))) > > + return 1; > > + mark_page_dirty(kvm, gfn); > > + kvm->arch.hv_tsc_page = data; > > break; > > } > > default: > > @@ -2253,6 +2278,17 @@ 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: { > > + u64 now_ns; > > + local_irq_disable(); > > + now_ns = get_kernel_ns() + kvm->arch.kvmclock_offset; > > + data = div_u64(now_ns - kvm->arch.hv_ref_count, 100); > > + local_irq_enable(); > > + break; > > + } > > local_irq_disable/enable not needed. > > It would be nice to have a testcase to compare reference tsc versus MSR. -- Gleb. -- 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