KVM: PPC: Book3S HV: Use msgsnd for signalling threads on POWER8

[karo-tx-linux.git] / arch / powerpc / kvm / book3s_hv.c

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index ea1600ff52b2fcc3fbc2a0a363b3bae26b97f12c..48d3c5d2ecc9ee83aab086715b3ffd6bf904d80a 100644 (file)
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -51,6 +51,7 @@
 #include <asm/hvcall.h>
 #include <asm/switch_to.h>
 #include <asm/smp.h>
+#include <asm/dbell.h>
 #include <linux/gfp.h>
 #include <linux/vmalloc.h>
 #include <linux/highmem.h>
@@ -84,9 +85,35 @@ static DECLARE_BITMAP(default_enabled_hcalls, MAX_HCALL_OPCODE/4 + 1);
 static void kvmppc_end_cede(struct kvm_vcpu *vcpu);
 static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu);
 
+static bool kvmppc_ipi_thread(int cpu)
+{
+       /* On POWER8 for IPIs to threads in the same core, use msgsnd */
+       if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
+               preempt_disable();
+               if (cpu_first_thread_sibling(cpu) ==
+                   cpu_first_thread_sibling(smp_processor_id())) {
+                       unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER);
+                       msg |= cpu_thread_in_core(cpu);
+                       smp_mb();
+                       __asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg));
+                       preempt_enable();
+                       return true;
+               }
+               preempt_enable();
+       }
+
+#if defined(CONFIG_PPC_ICP_NATIVE) && defined(CONFIG_SMP)
+       if (cpu >= 0 && cpu < nr_cpu_ids && paca[cpu].kvm_hstate.xics_phys) {
+               xics_wake_cpu(cpu);
+               return true;
+       }
+#endif
+
+       return false;
+}
+
 static void kvmppc_fast_vcpu_kick_hv(struct kvm_vcpu *vcpu)
 {
-       int me;
        int cpu = vcpu->cpu;
        wait_queue_head_t *wqp;
 
@@ -96,20 +123,12 @@ static void kvmppc_fast_vcpu_kick_hv(struct kvm_vcpu *vcpu)
                ++vcpu->stat.halt_wakeup;
        }
 
-       me = get_cpu();
+       if (kvmppc_ipi_thread(cpu + vcpu->arch.ptid))
+               return;
 
        /* CPU points to the first thread of the core */
-       if (cpu != me && cpu >= 0 && cpu < nr_cpu_ids) {
-#ifdef CONFIG_PPC_ICP_NATIVE
-               int real_cpu = cpu + vcpu->arch.ptid;
-               if (paca[real_cpu].kvm_hstate.xics_phys)
-                       xics_wake_cpu(real_cpu);
-               else
-#endif
-               if (cpu_online(cpu))
-                       smp_send_reschedule(cpu);
-       }
-       put_cpu();
+       if (cpu >= 0 && cpu < nr_cpu_ids && cpu_online(cpu))
+               smp_send_reschedule(cpu);
 }
 
 /*
@@ -1781,10 +1800,8 @@ static void kvmppc_start_thread(struct kvm_vcpu *vcpu)
        /* Order stores to hstate.kvm_vcore etc. before store to kvm_vcpu */
        smp_wmb();
        tpaca->kvm_hstate.kvm_vcpu = vcpu;
-#if defined(CONFIG_PPC_ICP_NATIVE) && defined(CONFIG_SMP)
        if (cpu != smp_processor_id())
-               xics_wake_cpu(cpu);
-#endif
+               kvmppc_ipi_thread(cpu);
 }
 
 static void kvmppc_wait_for_nap(void)
@@ -1933,7 +1950,7 @@ static void post_guest_process(struct kvmppc_vcore *vc)
  * Run a set of guest threads on a physical core.
  * Called with vc->lock held.
  */
-static void kvmppc_run_core(struct kvmppc_vcore *vc)
+static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
 {
        struct kvm_vcpu *vcpu;
        int i;