KVM: PPC: Book3S HV: Speed up wakeups of CPUs on HV KVM
Currently, we wake up a CPU by sending a host IPI with
smp_send_reschedule() to thread 0 of that core, which will take all
threads out of the guest, and cause them to re-evaluate their
interrupt status on the way back in.
This adds a mechanism to differentiate real host IPIs from IPIs sent
by KVM for guest threads to poke each other, in order to target the
guest threads precisely when possible and avoid that global switch of
the core to host state.
We then use this new facility in the in-kernel XICS code.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index 6582eed..1589fd8 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -264,6 +264,21 @@
paca[cpu].kvm_hstate.xics_phys = addr;
}
+static inline u32 kvmppc_get_xics_latch(void)
+{
+ u32 xirr = get_paca()->kvm_hstate.saved_xirr;
+
+ get_paca()->kvm_hstate.saved_xirr = 0;
+
+ return xirr;
+}
+
+static inline void kvmppc_set_host_ipi(int cpu, u8 host_ipi)
+{
+ paca[cpu].kvm_hstate.host_ipi = host_ipi;
+}
+
+extern void kvmppc_fast_vcpu_kick(struct kvm_vcpu *vcpu);
extern void kvm_linear_init(void);
#else
@@ -273,6 +288,18 @@
static inline void kvm_linear_init(void)
{}
+static inline u32 kvmppc_get_xics_latch(void)
+{
+ return 0;
+}
+
+static inline void kvmppc_set_host_ipi(int cpu, u8 host_ipi)
+{}
+
+static inline void kvmppc_fast_vcpu_kick(struct kvm_vcpu *vcpu)
+{
+ kvm_vcpu_kick(vcpu);
+}
#endif
#ifdef CONFIG_KVM_XICS
@@ -393,4 +420,6 @@
return ea;
}
+extern void xics_wake_cpu(int cpu);
+
#endif /* __POWERPC_KVM_PPC_H__ */