diff --git a/arch/powerpc/include/asm/kvm_book3s_asm.h b/arch/powerpc/include/asm/kvm_book3s_asm.h index 1f2f5b6..88609b2 100644 --- a/arch/powerpc/include/asm/kvm_book3s_asm.h +++ b/arch/powerpc/include/asm/kvm_book3s_asm.h @@ -79,6 +79,9 @@ struct kvmppc_host_state { u8 napping; #ifdef CONFIG_KVM_BOOK3S_64_HV + u8 hwthread_req; + u8 hwthread_state; + struct kvm_vcpu *kvm_vcpu; struct kvmppc_vcore *kvm_vcore; unsigned long xics_phys; @@ -122,4 +125,9 @@ struct kvmppc_book3s_shadow_vcpu { #endif /*__ASSEMBLY__ */ +/* Values for kvm_state */ +#define KVM_HWTHREAD_IN_KERNEL 0 +#define KVM_HWTHREAD_IN_NAP 1 +#define KVM_HWTHREAD_IN_KVM 2 + #endif /* __ASM_KVM_BOOK3S_ASM_H__ */ diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index a24f2c0..7133290 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -554,6 +554,8 @@ int main(void) HSTATE_FIELD(HSTATE_IN_GUEST, in_guest); HSTATE_FIELD(HSTATE_RESTORE_HID5, restore_hid5); HSTATE_FIELD(HSTATE_NAPPING, napping); + HSTATE_FIELD(HSTATE_HWTHREAD_REQ, hwthread_req); + HSTATE_FIELD(HSTATE_HWTHREAD_STATE, hwthread_state); #ifdef CONFIG_KVM_BOOK3S_64_HV HSTATE_FIELD(HSTATE_KVM_VCPU, kvm_vcpu); diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 8bea120..e9bd8a2 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -62,11 +62,13 @@ BEGIN_FTR_SECTION GET_PACA(r13) #ifdef CONFIG_KVM_BOOK3S_64_HV - lbz r0,PACAPROCSTART(r13) - cmpwi r0,0x80 - bne 1f - li r0,1 - stb r0,PACAPROCSTART(r13) + li r0,KVM_HWTHREAD_IN_KERNEL + stb r0,HSTATE_HWTHREAD_STATE(r13) + /* Order setting hwthread_state vs. testing hwthread_req */ + sync + lbz r0,HSTATE_HWTHREAD_REQ(r13) + cmpwi r0,0 + beq 1f b kvm_start_guest 1: #endif diff --git a/arch/powerpc/kernel/idle_power7.S b/arch/powerpc/kernel/idle_power7.S index fcdff19..95eb8c5 100644 --- a/arch/powerpc/kernel/idle_power7.S +++ b/arch/powerpc/kernel/idle_power7.S @@ -15,6 +15,7 @@ #include #include #include +#include #undef DEBUG @@ -64,6 +65,12 @@ _GLOBAL(power7_idle) std r9,_MSR(r1) std r1,PACAR1(r13) +#ifdef CONFIG_KVM_BOOK3S_64_HV + /* Tell KVM we're napping */ + li r4,KVM_HWTHREAD_IN_NAP + stb r4,HSTATE_HWTHREAD_STATE(r13) +#endif + /* Magic NAP mode enter sequence */ std r0,0(r1) ptesync diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index d386b61..1a5aa51 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -568,6 +568,45 @@ static void kvmppc_remove_runnable(struct kvmppc_vcore *vc, list_del(&vcpu->arch.run_list); } +static int kvmppc_grab_hwthread(int cpu) +{ + struct paca_struct *tpaca; + long timeout = 1000; + + tpaca = &paca[cpu]; + + /* Ensure the thread won't go into the kernel if it wakes */ + tpaca->kvm_hstate.hwthread_req = 1; + + /* + * If the thread is already executing in the kernel (e.g. handling + * a stray interrupt), wait for it to get back to nap mode. + * The smp_mb() is to ensure that our setting of hwthread_req + * is visible before we look at hwthread_state, so if this + * races with the code at system_reset_pSeries and the thread + * misses our setting of hwthread_req, we are sure to see its + * setting of hwthread_state, and vice versa. + */ + smp_mb(); + while (tpaca->kvm_hstate.hwthread_state == KVM_HWTHREAD_IN_KERNEL) { + if (--timeout <= 0) { + pr_err("KVM: couldn't grab cpu %d\n", cpu); + return -EBUSY; + } + udelay(1); + } + return 0; +} + +static void kvmppc_release_hwthread(int cpu) +{ + struct paca_struct *tpaca; + + tpaca = &paca[cpu]; + tpaca->kvm_hstate.hwthread_req = 0; + tpaca->kvm_hstate.kvm_vcpu = NULL; +} + static void kvmppc_start_thread(struct kvm_vcpu *vcpu) { int cpu; @@ -587,8 +626,7 @@ static void kvmppc_start_thread(struct kvm_vcpu *vcpu) smp_wmb(); #if defined(CONFIG_PPC_ICP_NATIVE) && defined(CONFIG_SMP) if (vcpu->arch.ptid) { - tpaca->cpu_start = 0x80; - wmb(); + kvmppc_grab_hwthread(cpu); xics_wake_cpu(cpu); ++vc->n_woken; } @@ -638,7 +676,7 @@ static int kvmppc_run_core(struct kvmppc_vcore *vc) struct kvm_vcpu *vcpu, *vcpu0, *vnext; long ret; u64 now; - int ptid; + int ptid, i; /* don't start if any threads have a signal pending */ list_for_each_entry(vcpu, &vc->runnable_threads, arch.run_list) @@ -685,12 +723,17 @@ static int kvmppc_run_core(struct kvmppc_vcore *vc) vc->napping_threads = 0; list_for_each_entry(vcpu, &vc->runnable_threads, arch.run_list) kvmppc_start_thread(vcpu); + /* Grab any remaining hw threads so they can't go into the kernel */ + for (i = ptid; i < threads_per_core; ++i) + kvmppc_grab_hwthread(vc->pcpu + i); preempt_disable(); spin_unlock(&vc->lock); kvm_guest_enter(); __kvmppc_vcore_entry(NULL, vcpu0); + for (i = 0; i < threads_per_core; ++i) + kvmppc_release_hwthread(vc->pcpu + i); spin_lock(&vc->lock); /* disable sending of IPIs on virtual external irqs */ diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index b70bf22..d595033 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -26,6 +26,7 @@ #include #include #include +#include /***************************************************************************** * * @@ -82,6 +83,7 @@ _GLOBAL(kvmppc_hv_entry_trampoline) #define XICS_XIRR 4 #define XICS_QIRR 0xc +#define XICS_IPI 2 /* interrupt source # for IPIs */ /* * We come in here when wakened from nap mode on a secondary hw thread. @@ -94,26 +96,54 @@ kvm_start_guest: subi r1,r1,STACK_FRAME_OVERHEAD ld r2,PACATOC(r13) - /* were we napping due to cede? */ - lbz r0,HSTATE_NAPPING(r13) - cmpwi r0,0 - bne kvm_end_cede + li r0,KVM_HWTHREAD_IN_KVM + stb r0,HSTATE_HWTHREAD_STATE(r13) - /* get vcpu pointer */ - ld r4, HSTATE_KVM_VCPU(r13) + /* NV GPR values from power7_idle() will no longer be valid */ + li r0,1 + stb r0,PACA_NAPSTATELOST(r13) - /* We got here with an IPI; clear it */ - ld r5, HSTATE_XICS_PHYS(r13) - li r0, 0xff - li r6, XICS_QIRR - li r7, XICS_XIRR - lwzcix r8, r5, r7 /* ack the interrupt */ + /* get vcpu pointer, NULL if we have no vcpu to run */ + ld r4,HSTATE_KVM_VCPU(r13) + cmpdi cr1,r4,0 + + /* Check the wake reason in SRR1 to see why we got here */ + mfspr r3,SPRN_SRR1 + rlwinm r3,r3,44-31,0x7 /* extract wake reason field */ + cmpwi r3,4 /* was it an external interrupt? */ + bne 27f + + /* + * External interrupt - for now assume it is an IPI, since we + * should never get any other interrupts sent to offline threads. + * Only do this for secondary threads. + */ + beq cr1,25f + lwz r3,VCPU_PTID(r4) + cmpwi r3,0 + beq 27f +25: ld r5,HSTATE_XICS_PHYS(r13) + li r0,0xff + li r6,XICS_QIRR + li r7,XICS_XIRR + lwzcix r8,r5,r7 /* get and ack the interrupt */ sync - stbcix r0, r5, r6 /* clear it */ - stwcix r8, r5, r7 /* EOI it */ + clrldi. r9,r8,40 /* get interrupt source ID. */ + beq 27f /* none there? */ + cmpwi r9,XICS_IPI + bne 26f + stbcix r0,r5,r6 /* clear IPI */ +26: stwcix r8,r5,r7 /* EOI the interrupt */ - /* NV GPR values from power7_idle() will no longer be valid */ - stb r0, PACA_NAPSTATELOST(r13) +27: /* XXX should handle hypervisor maintenance interrupts etc. here */ + + /* if we have no vcpu to run, go back to sleep */ + beq cr1,kvm_no_guest + + /* were we napping due to cede? */ + lbz r0,HSTATE_NAPPING(r13) + cmpwi r0,0 + bne kvm_end_cede .global kvmppc_hv_entry kvmppc_hv_entry: @@ -1445,8 +1475,8 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_206) * Take a nap until a decrementer or external interrupt occurs, * with PECE1 (wake on decr) and PECE0 (wake on external) set in LPCR */ - li r0,0x80 - stb r0,PACAPROCSTART(r13) + li r0,1 + stb r0,HSTATE_HWTHREAD_REQ(r13) mfspr r5,SPRN_LPCR ori r5,r5,LPCR_PECE0 | LPCR_PECE1 mtspr SPRN_LPCR,r5 @@ -1463,26 +1493,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_206) kvm_end_cede: /* Woken by external or decrementer interrupt */ ld r1, HSTATE_HOST_R1(r13) - ld r2, PACATOC(r13) - /* If we're a secondary thread and we got here by an IPI, ack it */ - ld r4,HSTATE_KVM_VCPU(r13) - lwz r3,VCPU_PTID(r4) - cmpwi r3,0 - beq 27f - mfspr r3,SPRN_SRR1 - rlwinm r3,r3,44-31,0x7 /* extract wake reason field */ - cmpwi r3,4 /* was it an external interrupt? */ - bne 27f - ld r5, HSTATE_XICS_PHYS(r13) - li r0,0xff - li r6,XICS_QIRR - li r7,XICS_XIRR - lwzcix r8,r5,r7 /* ack the interrupt */ - sync - stbcix r0,r5,r6 /* clear it */ - stwcix r8,r5,r7 /* EOI it */ -27: /* load up FP state */ bl kvmppc_load_fp @@ -1580,12 +1591,17 @@ secondary_nap: stwcx. r3, 0, r4 bne 51b +kvm_no_guest: + li r0, KVM_HWTHREAD_IN_NAP + stb r0, HSTATE_HWTHREAD_STATE(r13) + li r0, 0 + std r0, HSTATE_KVM_VCPU(r13) + li r3, LPCR_PECE0 mfspr r4, SPRN_LPCR rlwimi r4, r3, 0, LPCR_PECE0 | LPCR_PECE1 mtspr SPRN_LPCR, r4 isync - li r0, 0 std r0, HSTATE_SCRATCH0(r13) ptesync ld r0, HSTATE_SCRATCH0(r13)