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_book3s_asm.h b/arch/powerpc/include/asm/kvm_book3s_asm.h
index cdc3d27..9039d3c 100644
--- a/arch/powerpc/include/asm/kvm_book3s_asm.h
+++ b/arch/powerpc/include/asm/kvm_book3s_asm.h
@@ -20,6 +20,11 @@
#ifndef __ASM_KVM_BOOK3S_ASM_H__
#define __ASM_KVM_BOOK3S_ASM_H__
+/* XICS ICP register offsets */
+#define XICS_XIRR 4
+#define XICS_MFRR 0xc
+#define XICS_IPI 2 /* interrupt source # for IPIs */
+
#ifdef __ASSEMBLY__
#ifdef CONFIG_KVM_BOOK3S_HANDLER
@@ -81,10 +86,11 @@
#ifdef CONFIG_KVM_BOOK3S_64_HV
u8 hwthread_req;
u8 hwthread_state;
-
+ u8 host_ipi;
struct kvm_vcpu *kvm_vcpu;
struct kvmppc_vcore *kvm_vcore;
unsigned long xics_phys;
+ u32 saved_xirr;
u64 dabr;
u64 host_mmcr[3];
u32 host_pmc[8];
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__ */