diff options
Diffstat (limited to 'arch/powerpc/include/asm/paravirt.h')
| -rw-r--r-- | arch/powerpc/include/asm/paravirt.h | 33 |
1 files changed, 25 insertions, 8 deletions
diff --git a/arch/powerpc/include/asm/paravirt.h b/arch/powerpc/include/asm/paravirt.h index ac4279208d..b78b82d660 100644 --- a/arch/powerpc/include/asm/paravirt.h +++ b/arch/powerpc/include/asm/paravirt.h @@ -76,6 +76,17 @@ static inline bool is_vcpu_idle(int vcpu) { return lppaca_of(vcpu).idle; } + +static inline bool vcpu_is_dispatched(int vcpu) +{ + /* + * This is the yield_count. An "odd" value (low bit on) means that + * the processor is yielded (either because of an OS yield or a + * hypervisor preempt). An even value implies that the processor is + * currently executing. + */ + return (!(yield_count_of(vcpu) & 1)); +} #else static inline bool is_shared_processor(void) { @@ -109,6 +120,10 @@ static inline bool is_vcpu_idle(int vcpu) { return false; } +static inline bool vcpu_is_dispatched(int vcpu) +{ + return true; +} #endif #define vcpu_is_preempted vcpu_is_preempted @@ -134,12 +149,12 @@ static inline bool vcpu_is_preempted(int cpu) * If the hypervisor has dispatched the target CPU on a physical * processor, then the target CPU is definitely not preempted. */ - if (!(yield_count_of(cpu) & 1)) + if (vcpu_is_dispatched(cpu)) return false; /* - * If the target CPU has yielded to Hypervisor but OS has not - * requested idle then the target CPU is definitely preempted. + * if the target CPU is not dispatched and the guest OS + * has not marked the CPU idle, then it is hypervisor preempted. */ if (!is_vcpu_idle(cpu)) return true; @@ -166,7 +181,7 @@ static inline bool vcpu_is_preempted(int cpu) /* * The PowerVM hypervisor dispatches VMs on a whole core - * basis. So we know that a thread sibling of the local CPU + * basis. So we know that a thread sibling of the executing CPU * cannot have been preempted by the hypervisor, even if it * has called H_CONFER, which will set the yield bit. */ @@ -174,15 +189,17 @@ static inline bool vcpu_is_preempted(int cpu) return false; /* - * If any of the threads of the target CPU's core are not - * preempted or ceded, then consider target CPU to be - * non-preempted. + * The specific target CPU was marked by guest OS as idle, but + * then also check all other cpus in the core for PowerVM + * because it does core scheduling and one of the vcpu + * of the core getting preempted by hypervisor implies + * other vcpus can also be considered preempted. */ first_cpu = cpu_first_thread_sibling(cpu); for (i = first_cpu; i < first_cpu + threads_per_core; i++) { if (i == cpu) continue; - if (!(yield_count_of(i) & 1)) + if (vcpu_is_dispatched(i)) return false; if (!is_vcpu_idle(i)) return true; |