Re: [PATCH RFC V9 18/19] Documentation/kvm : Add documentation on Hypercalls and features used for PV spinlock
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 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 Signed-off-by: Raghavendra K T --- 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 majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH RFC V9 18/19] Documentation/kvm : Add documentation on Hypercalls and features used for PV spinlock
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 > > 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 > Signed-off-by: Raghavendra K T > --- > 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 majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH RFC V9 18/19] Documentation/kvm : Add documentation on Hypercalls and features used for PV spinlock
Documentation/kvm : Add documentation on Hypercalls and features used for PV spinlock From: Raghavendra K T 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 Signed-off-by: Raghavendra K T --- 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. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
