| Message ID | 1389691337-12050-3-git-send-email-vrozenfe@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
The cleanup between v3 and v4 is really nice; thanks. What happened to the glitch you reported in the v3 thread. Il 14/01/2014 10:22, Vadim Rozenfeld ha scritto: > + tsc_ref.tsc_scale = ((10000LL << 32) / > + vcpu->arch.virtual_tsc_khz) << 32; As mentioned in the review of v3, I don't really like the tsc_scale to come from two different sources in the two cases of MSR write and KVM_SET_CLOCK. This is the only qualm I still have with this patch. Marcelo, do you have any ideas? Paolo > + tsc_ref.tsc_offset = kvm->arch.kvmclock_offset; > + } > if (__copy_to_user((void __user *)addr, &tsc_ref, sizeof(tsc_ref))) > return 1; > mark_page_dirty(kvm, gfn); > @@ -3871,6 +3879,27 @@ long kvm_arch_vm_ioctl(struct file *filp, > local_irq_enable(); > kvm->arch.kvmclock_offset = delta; > kvm_gen_update_masterclock(kvm); > + if (kvm->arch.hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE) { > + HV_REFERENCE_TSC_PAGE tsc_ref; > + struct kvm_arch *ka = &kvm->arch; > + r = kvm_read_guest(kvm, kvm->arch.hv_tsc_page, > + &tsc_ref, sizeof(tsc_ref)); > + if (r) > + goto out; > + if (tsc_ref.tsc_sequence > + && boot_cpu_has(X86_FEATURE_CONSTANT_TSC) > + && ka->use_master_clock) { > + tsc_ref.tsc_sequence++; > + tsc_ref.tsc_scale = ((10000LL << 32) / > + __get_cpu_var(cpu_tsc_khz)) << 32; -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Jan 14, 2014 at 12:03:24PM +0100, Paolo Bonzini wrote: > The cleanup between v3 and v4 is really nice; thanks. What happened to > the glitch you reported in the v3 thread. > > Il 14/01/2014 10:22, Vadim Rozenfeld ha scritto: > > + tsc_ref.tsc_scale = ((10000LL << 32) / > > + vcpu->arch.virtual_tsc_khz) << 32; > > As mentioned in the review of v3, I don't really like the tsc_scale to > come from two different sources in the two cases of MSR write and > KVM_SET_CLOCK. This is the only qualm I still have with this patch. > Marcelo, do you have any ideas? It should be at kvm_guest_time_update. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Jan 14, 2014 at 08:22:17PM +1100, Vadim Rozenfeld wrote: > The following patch allows to activate a partition reference > time enlightenment that is based on the host platform's support > for an Invariant Time Stamp Counter (iTSC). > > v2 -> v3 > Handle TSC sequence, scale, and offest changing during migration. > > v3 -> v4 > 1. Wrap access to iTSC page with kvm_read_guest/kvm_write_guest > suggested by Andrew Honig <ahonig@google.com> and Marcelo > 2. iTSC data calculation/access fixes suggested by Marcelo and Paolo > > --- > arch/x86/kvm/x86.c | 29 +++++++++++++++++++++++++++++ > 1 file changed, 29 insertions(+) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 496bdb1..6e6debf 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -1873,6 +1873,7 @@ static int set_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data) > case HV_X64_MSR_REFERENCE_TSC: { > u64 gfn; > unsigned long addr; > + struct kvm_arch *ka = &kvm->arch; > HV_REFERENCE_TSC_PAGE tsc_ref; > memset(&tsc_ref, 0, sizeof(tsc_ref)); > if (!(data & HV_X64_MSR_TSC_REFERENCE_ENABLE)) { > @@ -1883,6 +1884,13 @@ static int set_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data) > addr = gfn_to_hva(kvm, gfn); > if (kvm_is_error_hva(addr)) > return 1; > + if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) > + && ka->use_master_clock) { > + tsc_ref.tsc_sequence = 1; > + tsc_ref.tsc_scale = ((10000LL << 32) / > + vcpu->arch.virtual_tsc_khz) << 32; > + tsc_ref.tsc_offset = kvm->arch.kvmclock_offset; > + } > if (__copy_to_user((void __user *)addr, &tsc_ref, sizeof(tsc_ref))) > return 1; > mark_page_dirty(kvm, gfn); > @@ -3871,6 +3879,27 @@ long kvm_arch_vm_ioctl(struct file *filp, > local_irq_enable(); > kvm->arch.kvmclock_offset = delta; > kvm_gen_update_masterclock(kvm); > + if (kvm->arch.hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE) { > + HV_REFERENCE_TSC_PAGE tsc_ref; > + struct kvm_arch *ka = &kvm->arch; > + r = kvm_read_guest(kvm, kvm->arch.hv_tsc_page, > + &tsc_ref, sizeof(tsc_ref)); > + if (r) > + goto out; > + if (tsc_ref.tsc_sequence > + && boot_cpu_has(X86_FEATURE_CONSTANT_TSC) > + && ka->use_master_clock) { > + tsc_ref.tsc_sequence++; > + tsc_ref.tsc_scale = ((10000LL << 32) / > + __get_cpu_var(cpu_tsc_khz)) << 32; > + tsc_ref.tsc_offset = kvm->arch.kvmclock_offset; > + } else > + tsc_ref.tsc_sequence = 0; > + r = kvm_write_guest(kvm, kvm->arch.hv_tsc_page, > + &tsc_ref, sizeof(tsc_ref)); > + if (r) > + goto out; > + } > break; > } Vadim, A short comment explaining the lifecycle of the exposed clock would be nice. Can you explain why are you setting tsc_offset to kvmclock_offset? -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Il 14/01/2014 10:22, Vadim Rozenfeld ha scritto: > @@ -1883,6 +1884,13 @@ static int set_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data) > addr = gfn_to_hva(kvm, gfn); > if (kvm_is_error_hva(addr)) > return 1; > + if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) > + && ka->use_master_clock) { > + tsc_ref.tsc_sequence = 1; I think that after the first migration the sequence number will always be 2: set_msr_hyperv_pw will set it to 1, and KVM_SET_KVMCLOCK will increment it. Can you check this? The solution would be to propagate the "struct msr_data *" argument from kvm_set_msr_common to kvm_set_msr_hyper_pw. Then, here in this "if" you can test msr_info->host_initiated, and increment the tsc_sequence instead of resetting. Like if ((!msr_info->host_initiated || tsc_ref.tsc_sequence) && boot_cpu_has(X86_FEATURE_CONSTANT_TSC) && ka->use_master_clock) { tsc_ref.tsc_sequence = msr_info->host_initiated ? tsc_ref.tsc_sequence + 1 : 1; > + tsc_ref.tsc_scale = ((10000LL << 32) / > + vcpu->arch.virtual_tsc_khz) << 32; > + tsc_ref.tsc_offset = kvm->arch.kvmclock_offset; > + } > if (__copy_to_user((void __user *)addr, &tsc_ref, sizeof(tsc_ref))) > return 1; > mark_page_dirty(kvm, gfn); > @@ -3871,6 +3879,27 @@ long kvm_arch_vm_ioctl(struct file *filp, > local_irq_enable(); > kvm->arch.kvmclock_offset = delta; > kvm_gen_update_masterclock(kvm); > + if (kvm->arch.hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE) { > + HV_REFERENCE_TSC_PAGE tsc_ref; > + struct kvm_arch *ka = &kvm->arch; > + r = kvm_read_guest(kvm, kvm->arch.hv_tsc_page, > + &tsc_ref, sizeof(tsc_ref)); > + if (r) > + goto out; > + if (tsc_ref.tsc_sequence > + && boot_cpu_has(X86_FEATURE_CONSTANT_TSC) > + && ka->use_master_clock) { > + tsc_ref.tsc_sequence++; > + tsc_ref.tsc_scale = ((10000LL << 32) / > + __get_cpu_var(cpu_tsc_khz)) << 32; Since on migration kvm_set_hyperv_pw will always be called, do you need to write tsc_ref.scale at all here? Paolo > + tsc_ref.tsc_offset = kvm->arch.kvmclock_offset; > + } else > + tsc_ref.tsc_sequence = 0; > + r = kvm_write_guest(kvm, kvm->arch.hv_tsc_page, > + &tsc_ref, sizeof(tsc_ref)); > + if (r) > + goto out; > + } > break; > } > case KVM_GET_CLOCK: { > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 496bdb1..6e6debf 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1873,6 +1873,7 @@ static int set_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data) case HV_X64_MSR_REFERENCE_TSC: { u64 gfn; unsigned long addr; + struct kvm_arch *ka = &kvm->arch; HV_REFERENCE_TSC_PAGE tsc_ref; memset(&tsc_ref, 0, sizeof(tsc_ref)); if (!(data & HV_X64_MSR_TSC_REFERENCE_ENABLE)) { @@ -1883,6 +1884,13 @@ static int set_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data) addr = gfn_to_hva(kvm, gfn); if (kvm_is_error_hva(addr)) return 1; + if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) + && ka->use_master_clock) { + tsc_ref.tsc_sequence = 1; + tsc_ref.tsc_scale = ((10000LL << 32) / + vcpu->arch.virtual_tsc_khz) << 32; + tsc_ref.tsc_offset = kvm->arch.kvmclock_offset; + } if (__copy_to_user((void __user *)addr, &tsc_ref, sizeof(tsc_ref))) return 1; mark_page_dirty(kvm, gfn); @@ -3871,6 +3879,27 @@ long kvm_arch_vm_ioctl(struct file *filp, local_irq_enable(); kvm->arch.kvmclock_offset = delta; kvm_gen_update_masterclock(kvm); + if (kvm->arch.hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE) { + HV_REFERENCE_TSC_PAGE tsc_ref; + struct kvm_arch *ka = &kvm->arch; + r = kvm_read_guest(kvm, kvm->arch.hv_tsc_page, + &tsc_ref, sizeof(tsc_ref)); + if (r) + goto out; + if (tsc_ref.tsc_sequence + && boot_cpu_has(X86_FEATURE_CONSTANT_TSC) + && ka->use_master_clock) { + tsc_ref.tsc_sequence++; + tsc_ref.tsc_scale = ((10000LL << 32) / + __get_cpu_var(cpu_tsc_khz)) << 32; + tsc_ref.tsc_offset = kvm->arch.kvmclock_offset; + } else + tsc_ref.tsc_sequence = 0; + r = kvm_write_guest(kvm, kvm->arch.hv_tsc_page, + &tsc_ref, sizeof(tsc_ref)); + if (r) + goto out; + } break; } case KVM_GET_CLOCK: {
The following patch allows to activate a partition reference time enlightenment that is based on the host platform's support for an Invariant Time Stamp Counter (iTSC). v2 -> v3 Handle TSC sequence, scale, and offest changing during migration. v3 -> v4 1. Wrap access to iTSC page with kvm_read_guest/kvm_write_guest suggested by Andrew Honig <ahonig@google.com> and Marcelo 2. iTSC data calculation/access fixes suggested by Marcelo and Paolo --- arch/x86/kvm/x86.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+)