| Message ID | 20130601192624.5966.97025.sendpatchset@codeblue (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sun, Jun 02, 2013 at 12:56:24AM +0530, Raghavendra K T wrote: > Documentation/kvm : Add documentation on Hypercalls and features used for PV spinlock > > From: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> > > KVM_HC_KICK_CPU hypercall added to wakeup halted vcpu in paravirtual spinlock > enabled guest. > > KVM_FEATURE_PV_UNHALT enables guest to check whether pv spinlock can be enabled > in guest. > > Thanks Vatsa for rewriting KVM_HC_KICK_CPU > > Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> > Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> > --- > Documentation/virtual/kvm/cpuid.txt | 4 ++++ > Documentation/virtual/kvm/hypercalls.txt | 13 +++++++++++++ > 2 files changed, 17 insertions(+) > > diff --git a/Documentation/virtual/kvm/cpuid.txt b/Documentation/virtual/kvm/cpuid.txt > index 83afe65..654f43c 100644 > --- a/Documentation/virtual/kvm/cpuid.txt > +++ b/Documentation/virtual/kvm/cpuid.txt > @@ -43,6 +43,10 @@ KVM_FEATURE_CLOCKSOURCE2 || 3 || kvmclock available at msrs > KVM_FEATURE_ASYNC_PF || 4 || async pf can be enabled by > || || writing to msr 0x4b564d02 > ------------------------------------------------------------------------------ > +KVM_FEATURE_PV_UNHALT || 6 || guest checks this feature bit > + || || before enabling paravirtualized > + || || spinlock support. > +------------------------------------------------------------------------------ > KVM_FEATURE_CLOCKSOURCE_STABLE_BIT || 24 || host will warn if no guest-side > || || per-cpu warps are expected in > || || kvmclock. > diff --git a/Documentation/virtual/kvm/hypercalls.txt b/Documentation/virtual/kvm/hypercalls.txt > index ea113b5..2a4da11 100644 > --- a/Documentation/virtual/kvm/hypercalls.txt > +++ b/Documentation/virtual/kvm/hypercalls.txt > @@ -64,3 +64,16 @@ Purpose: To enable communication between the hypervisor and guest there is a > shared page that contains parts of supervisor visible register state. > The guest can map this shared page to access its supervisor register through > memory using this hypercall. > + > +5. KVM_HC_KICK_CPU > +------------------------ > +Architecture: x86 > +Status: active > +Purpose: Hypercall used to wakeup a vcpu from HLT state > +Usage example : A vcpu of a paravirtualized guest that is busywaiting in guest > +kernel mode for an event to occur (ex: a spinlock to become available) can > +execute HLT instruction once it has busy-waited for more than a threshold > +time-interval. Execution of HLT instruction would cause the hypervisor to put > +the vcpu to sleep until occurence of an appropriate event. Another vcpu of the > +same guest can wakeup the sleeping vcpu by issuing KVM_HC_KICK_CPU hypercall, > +specifying APIC ID of the vcpu to be wokenup. woken up. > -- 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 06/03/2013 09:34 PM, Konrad Rzeszutek Wilk wrote: > On Sun, Jun 02, 2013 at 12:56:24AM +0530, Raghavendra K T wrote: >> Documentation/kvm : Add documentation on Hypercalls and features used for PV spinlock >> >> From: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> >> >> KVM_HC_KICK_CPU hypercall added to wakeup halted vcpu in paravirtual spinlock >> enabled guest. >> >> KVM_FEATURE_PV_UNHALT enables guest to check whether pv spinlock can be enabled >> in guest. >> >> Thanks Vatsa for rewriting KVM_HC_KICK_CPU >> >> Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> >> Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> >> --- >> Documentation/virtual/kvm/cpuid.txt | 4 ++++ >> Documentation/virtual/kvm/hypercalls.txt | 13 +++++++++++++ >> 2 files changed, 17 insertions(+) >> >> diff --git a/Documentation/virtual/kvm/cpuid.txt b/Documentation/virtual/kvm/cpuid.txt >> index 83afe65..654f43c 100644 >> --- a/Documentation/virtual/kvm/cpuid.txt >> +++ b/Documentation/virtual/kvm/cpuid.txt >> @@ -43,6 +43,10 @@ KVM_FEATURE_CLOCKSOURCE2 || 3 || kvmclock available at msrs >> KVM_FEATURE_ASYNC_PF || 4 || async pf can be enabled by >> || || writing to msr 0x4b564d02 >> ------------------------------------------------------------------------------ >> +KVM_FEATURE_PV_UNHALT || 6 || guest checks this feature bit >> + || || before enabling paravirtualized >> + || || spinlock support. >> +------------------------------------------------------------------------------ >> KVM_FEATURE_CLOCKSOURCE_STABLE_BIT || 24 || host will warn if no guest-side >> || || per-cpu warps are expected in >> || || kvmclock. >> diff --git a/Documentation/virtual/kvm/hypercalls.txt b/Documentation/virtual/kvm/hypercalls.txt >> index ea113b5..2a4da11 100644 >> --- a/Documentation/virtual/kvm/hypercalls.txt >> +++ b/Documentation/virtual/kvm/hypercalls.txt >> @@ -64,3 +64,16 @@ Purpose: To enable communication between the hypervisor and guest there is a >> shared page that contains parts of supervisor visible register state. >> The guest can map this shared page to access its supervisor register through >> memory using this hypercall. >> + >> +5. KVM_HC_KICK_CPU >> +------------------------ >> +Architecture: x86 >> +Status: active >> +Purpose: Hypercall used to wakeup a vcpu from HLT state >> +Usage example : A vcpu of a paravirtualized guest that is busywaiting in guest >> +kernel mode for an event to occur (ex: a spinlock to become available) can >> +execute HLT instruction once it has busy-waited for more than a threshold >> +time-interval. Execution of HLT instruction would cause the hypervisor to put >> +the vcpu to sleep until occurence of an appropriate event. Another vcpu of the >> +same guest can wakeup the sleeping vcpu by issuing KVM_HC_KICK_CPU hypercall, >> +specifying APIC ID of the vcpu to be wokenup. > > woken up. Yep. :) -- 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/Documentation/virtual/kvm/cpuid.txt b/Documentation/virtual/kvm/cpuid.txt index 83afe65..654f43c 100644 --- a/Documentation/virtual/kvm/cpuid.txt +++ b/Documentation/virtual/kvm/cpuid.txt @@ -43,6 +43,10 @@ KVM_FEATURE_CLOCKSOURCE2 || 3 || kvmclock available at msrs KVM_FEATURE_ASYNC_PF || 4 || async pf can be enabled by || || writing to msr 0x4b564d02 ------------------------------------------------------------------------------ +KVM_FEATURE_PV_UNHALT || 6 || guest checks this feature bit + || || before enabling paravirtualized + || || spinlock support. +------------------------------------------------------------------------------ KVM_FEATURE_CLOCKSOURCE_STABLE_BIT || 24 || host will warn if no guest-side || || per-cpu warps are expected in || || kvmclock. diff --git a/Documentation/virtual/kvm/hypercalls.txt b/Documentation/virtual/kvm/hypercalls.txt index ea113b5..2a4da11 100644 --- a/Documentation/virtual/kvm/hypercalls.txt +++ b/Documentation/virtual/kvm/hypercalls.txt @@ -64,3 +64,16 @@ Purpose: To enable communication between the hypervisor and guest there is a shared page that contains parts of supervisor visible register state. The guest can map this shared page to access its supervisor register through memory using this hypercall. + +5. KVM_HC_KICK_CPU +------------------------ +Architecture: x86 +Status: active +Purpose: Hypercall used to wakeup a vcpu from HLT state +Usage example : A vcpu of a paravirtualized guest that is busywaiting in guest +kernel mode for an event to occur (ex: a spinlock to become available) can +execute HLT instruction once it has busy-waited for more than a threshold +time-interval. Execution of HLT instruction would cause the hypervisor to put +the vcpu to sleep until occurence of an appropriate event. Another vcpu of the +same guest can wakeup the sleeping vcpu by issuing KVM_HC_KICK_CPU hypercall, +specifying APIC ID of the vcpu to be wokenup.