| Message ID | 1482866480-26208-3-git-send-email-ehabkost@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Dec 27, 2016 at 05:21:18PM -0200, Eduardo Habkost wrote: > We can safely allow a VM to be migrated with invtsc enabled if > tsc-khz is set explicitly, because QEMU already refuses to start > if it can't set the TSC frequency to the configured value. On the source host, yes, but on the destination it does not. SOURCE: -cpu kvm64,tsc-frequency=2660001000 DESTINATION: -cpu kvm64 Only prints: qemu-system-x86_64: warning: TSC frequency mismatch between VM (2660001 kHz) and host (2893428 kHz), and TSC scaling unavailable qemu-system-x86_64: warning: TSC frequency mismatch between VM (2660001 kHz) and host (2893428 kHz), and TSC scaling unavailable And allows migration. > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> > --- > target/i386/kvm.c | 19 ++++++++++--------- > 1 file changed, 10 insertions(+), 9 deletions(-) > > diff --git a/target/i386/kvm.c b/target/i386/kvm.c > index a26290f..6a51399 100644 > --- a/target/i386/kvm.c > +++ b/target/i386/kvm.c > @@ -962,15 +962,16 @@ int kvm_arch_init_vcpu(CPUState *cs) > has_msr_mcg_ext_ctl = has_msr_feature_control = true; > } > > - if ((env->features[FEAT_8000_0007_EDX] & CPUID_APM_INVTSC) && > - invtsc_mig_blocker == NULL) { > - /* for migration */ > - error_setg(&invtsc_mig_blocker, > - "State blocked by non-migratable CPU device" > - " (invtsc flag)"); > - migrate_add_blocker(invtsc_mig_blocker); > - /* for savevm */ > - vmstate_x86_cpu.unmigratable = 1; > + if (!env->user_tsc_khz) { > + if ((env->features[FEAT_8000_0007_EDX] & CPUID_APM_INVTSC) && > + invtsc_mig_blocker == NULL) { > + /* for migration */ > + error_setg(&invtsc_mig_blocker, > + "State blocked by non-migratable CPU device" > + " (invtsc flag)"); > + migrate_add_blocker(invtsc_mig_blocker); > + /* for savevm */ > + vmstate_x86_cpu.unmigratable = 1; > } > > cpuid_data.cpuid.padding = 0; > -- > 2.7.4
On Wed, Jan 04, 2017 at 09:44:06AM -0200, Marcelo Tosatti wrote: > On Tue, Dec 27, 2016 at 05:21:18PM -0200, Eduardo Habkost wrote: > > We can safely allow a VM to be migrated with invtsc enabled if > > tsc-khz is set explicitly, because QEMU already refuses to start > > if it can't set the TSC frequency to the configured value. > > On the source host, yes, but on the destination it does not. > > SOURCE: -cpu kvm64,tsc-frequency=2660001000 > DESTINATION: -cpu kvm64 > > Only prints: > > qemu-system-x86_64: warning: TSC frequency mismatch between VM (2660001 > kHz) and host (2893428 kHz), and TSC scaling unavailable > qemu-system-x86_64: warning: TSC frequency mismatch between VM (2660001 > kHz) and host (2893428 kHz), and TSC scaling unavailable > > And allows migration. Ignore that comment, patch 4 deals with it.
On Wed, Jan 04, 2017 at 09:44:06AM -0200, Marcelo Tosatti wrote: > On Tue, Dec 27, 2016 at 05:21:18PM -0200, Eduardo Habkost wrote: > > We can safely allow a VM to be migrated with invtsc enabled if > > tsc-khz is set explicitly, because QEMU already refuses to start > > if it can't set the TSC frequency to the configured value. > > On the source host, yes, but on the destination it does not. > > SOURCE: -cpu kvm64,tsc-frequency=2660001000 > DESTINATION: -cpu kvm64 This is invalid usage. Management software is responsible for keeping the same configuration on source and destination. > > Only prints: > > qemu-system-x86_64: warning: TSC frequency mismatch between VM (2660001 > kHz) and host (2893428 kHz), and TSC scaling unavailable > qemu-system-x86_64: warning: TSC frequency mismatch between VM (2660001 > kHz) and host (2893428 kHz), and TSC scaling unavailable > > And allows migration. > > > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> > > --- > > target/i386/kvm.c | 19 ++++++++++--------- > > 1 file changed, 10 insertions(+), 9 deletions(-) > > > > diff --git a/target/i386/kvm.c b/target/i386/kvm.c > > index a26290f..6a51399 100644 > > --- a/target/i386/kvm.c > > +++ b/target/i386/kvm.c > > @@ -962,15 +962,16 @@ int kvm_arch_init_vcpu(CPUState *cs) > > has_msr_mcg_ext_ctl = has_msr_feature_control = true; > > } > > > > - if ((env->features[FEAT_8000_0007_EDX] & CPUID_APM_INVTSC) && > > - invtsc_mig_blocker == NULL) { > > - /* for migration */ > > - error_setg(&invtsc_mig_blocker, > > - "State blocked by non-migratable CPU device" > > - " (invtsc flag)"); > > - migrate_add_blocker(invtsc_mig_blocker); > > - /* for savevm */ > > - vmstate_x86_cpu.unmigratable = 1; > > + if (!env->user_tsc_khz) { > > + if ((env->features[FEAT_8000_0007_EDX] & CPUID_APM_INVTSC) && > > + invtsc_mig_blocker == NULL) { > > + /* for migration */ > > + error_setg(&invtsc_mig_blocker, > > + "State blocked by non-migratable CPU device" > > + " (invtsc flag)"); > > + migrate_add_blocker(invtsc_mig_blocker); > > + /* for savevm */ > > + vmstate_x86_cpu.unmigratable = 1; > > } > > > > cpuid_data.cpuid.padding = 0; > > -- > > 2.7.4
On Wed, Jan 04, 2017 at 11:40:17AM -0200, Eduardo Habkost wrote: > On Wed, Jan 04, 2017 at 09:44:06AM -0200, Marcelo Tosatti wrote: > > On Tue, Dec 27, 2016 at 05:21:18PM -0200, Eduardo Habkost wrote: > > > We can safely allow a VM to be migrated with invtsc enabled if > > > tsc-khz is set explicitly, because QEMU already refuses to start > > > if it can't set the TSC frequency to the configured value. > > > > On the source host, yes, but on the destination it does not. > > > > SOURCE: -cpu kvm64,tsc-frequency=2660001000 > > DESTINATION: -cpu kvm64 > > This is invalid usage. Management software is responsible for > keeping the same configuration on source and destination. Fine. Just to confirm: you do not expect libvirt to use -cpu XXX,tsc-frequency=ZZZZZ On both source and destination, correct? > > Only prints: > > > > qemu-system-x86_64: warning: TSC frequency mismatch between VM (2660001 > > kHz) and host (2893428 kHz), and TSC scaling unavailable > > qemu-system-x86_64: warning: TSC frequency mismatch between VM (2660001 > > kHz) and host (2893428 kHz), and TSC scaling unavailable > > > > And allows migration. > > > > > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> > > > --- > > > target/i386/kvm.c | 19 ++++++++++--------- > > > 1 file changed, 10 insertions(+), 9 deletions(-) > > > > > > diff --git a/target/i386/kvm.c b/target/i386/kvm.c > > > index a26290f..6a51399 100644 > > > --- a/target/i386/kvm.c > > > +++ b/target/i386/kvm.c > > > @@ -962,15 +962,16 @@ int kvm_arch_init_vcpu(CPUState *cs) > > > has_msr_mcg_ext_ctl = has_msr_feature_control = true; > > > } > > > > > > - if ((env->features[FEAT_8000_0007_EDX] & CPUID_APM_INVTSC) && > > > - invtsc_mig_blocker == NULL) { > > > - /* for migration */ > > > - error_setg(&invtsc_mig_blocker, > > > - "State blocked by non-migratable CPU device" > > > - " (invtsc flag)"); > > > - migrate_add_blocker(invtsc_mig_blocker); > > > - /* for savevm */ > > > - vmstate_x86_cpu.unmigratable = 1; > > > + if (!env->user_tsc_khz) { > > > + if ((env->features[FEAT_8000_0007_EDX] & CPUID_APM_INVTSC) && > > > + invtsc_mig_blocker == NULL) { > > > + /* for migration */ > > > + error_setg(&invtsc_mig_blocker, > > > + "State blocked by non-migratable CPU device" > > > + " (invtsc flag)"); > > > + migrate_add_blocker(invtsc_mig_blocker); > > > + /* for savevm */ > > > + vmstate_x86_cpu.unmigratable = 1; > > > } > > > > > > cpuid_data.cpuid.padding = 0; > > > -- > > > 2.7.4 > > -- > Eduardo > -- > 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 Wed, Jan 04, 2017 at 11:45:36AM -0200, Marcelo Tosatti wrote: > On Wed, Jan 04, 2017 at 11:40:17AM -0200, Eduardo Habkost wrote: > > On Wed, Jan 04, 2017 at 09:44:06AM -0200, Marcelo Tosatti wrote: > > > On Tue, Dec 27, 2016 at 05:21:18PM -0200, Eduardo Habkost wrote: > > > > We can safely allow a VM to be migrated with invtsc enabled if > > > > tsc-khz is set explicitly, because QEMU already refuses to start > > > > if it can't set the TSC frequency to the configured value. > > > > > > On the source host, yes, but on the destination it does not. > > > > > > SOURCE: -cpu kvm64,tsc-frequency=2660001000 > > > DESTINATION: -cpu kvm64 > > > > This is invalid usage. Management software is responsible for > > keeping the same configuration on source and destination. > > Fine. Just to confirm: you do not expect libvirt to > use > > -cpu XXX,tsc-frequency=ZZZZZ > > On both source and destination, correct? They can omit it, as long as it is omitted on both source and destination. If they do use tsc-frequency on the source, they must use it on the destination as well. Just like they do for every device option in QEMU. > > > > Only prints: > > > > > > qemu-system-x86_64: warning: TSC frequency mismatch between VM (2660001 > > > kHz) and host (2893428 kHz), and TSC scaling unavailable > > > qemu-system-x86_64: warning: TSC frequency mismatch between VM (2660001 > > > kHz) and host (2893428 kHz), and TSC scaling unavailable > > > > > > And allows migration. > > > > > > > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> > > > > --- > > > > target/i386/kvm.c | 19 ++++++++++--------- > > > > 1 file changed, 10 insertions(+), 9 deletions(-) > > > > > > > > diff --git a/target/i386/kvm.c b/target/i386/kvm.c > > > > index a26290f..6a51399 100644 > > > > --- a/target/i386/kvm.c > > > > +++ b/target/i386/kvm.c > > > > @@ -962,15 +962,16 @@ int kvm_arch_init_vcpu(CPUState *cs) > > > > has_msr_mcg_ext_ctl = has_msr_feature_control = true; > > > > } > > > > > > > > - if ((env->features[FEAT_8000_0007_EDX] & CPUID_APM_INVTSC) && > > > > - invtsc_mig_blocker == NULL) { > > > > - /* for migration */ > > > > - error_setg(&invtsc_mig_blocker, > > > > - "State blocked by non-migratable CPU device" > > > > - " (invtsc flag)"); > > > > - migrate_add_blocker(invtsc_mig_blocker); > > > > - /* for savevm */ > > > > - vmstate_x86_cpu.unmigratable = 1; > > > > + if (!env->user_tsc_khz) { > > > > + if ((env->features[FEAT_8000_0007_EDX] & CPUID_APM_INVTSC) && > > > > + invtsc_mig_blocker == NULL) { > > > > + /* for migration */ > > > > + error_setg(&invtsc_mig_blocker, > > > > + "State blocked by non-migratable CPU device" > > > > + " (invtsc flag)"); > > > > + migrate_add_blocker(invtsc_mig_blocker); > > > > + /* for savevm */ > > > > + vmstate_x86_cpu.unmigratable = 1; > > > > } > > > > > > > > cpuid_data.cpuid.padding = 0; > > > > -- > > > > 2.7.4 > > > > -- > > Eduardo > > -- > > 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/target/i386/kvm.c b/target/i386/kvm.c index a26290f..6a51399 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -962,15 +962,16 @@ int kvm_arch_init_vcpu(CPUState *cs) has_msr_mcg_ext_ctl = has_msr_feature_control = true; } - if ((env->features[FEAT_8000_0007_EDX] & CPUID_APM_INVTSC) && - invtsc_mig_blocker == NULL) { - /* for migration */ - error_setg(&invtsc_mig_blocker, - "State blocked by non-migratable CPU device" - " (invtsc flag)"); - migrate_add_blocker(invtsc_mig_blocker); - /* for savevm */ - vmstate_x86_cpu.unmigratable = 1; + if (!env->user_tsc_khz) { + if ((env->features[FEAT_8000_0007_EDX] & CPUID_APM_INVTSC) && + invtsc_mig_blocker == NULL) { + /* for migration */ + error_setg(&invtsc_mig_blocker, + "State blocked by non-migratable CPU device" + " (invtsc flag)"); + migrate_add_blocker(invtsc_mig_blocker); + /* for savevm */ + vmstate_x86_cpu.unmigratable = 1; } cpuid_data.cpuid.padding = 0;
We can safely allow a VM to be migrated with invtsc enabled if tsc-khz is set explicitly, because QEMU already refuses to start if it can't set the TSC frequency to the configured value. Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> --- target/i386/kvm.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-)