diff options
| -rw-r--r-- | arch/powerpc/include/asm/kvm_host.h | 1 | ||||
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv.c | 41 | ||||
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv_builtin.c | 32 | ||||
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv_rmhandlers.S | 2 |
4 files changed, 74 insertions, 2 deletions
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 65441875b025..7efd666a3fa7 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -295,6 +295,7 @@ struct kvmppc_vcore { ulong dpdes; /* doorbell state (POWER8) */ void *mpp_buffer; /* Micro Partition Prefetch buffer */ bool mpp_buffer_is_valid; + ulong conferring_threads; }; #define VCORE_ENTRY_COUNT(vc) ((vc)->entry_exit_count & 0xff) diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 299351e77eb9..de4018a1bc4b 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -607,10 +607,45 @@ static int kvmppc_h_set_mode(struct kvm_vcpu *vcpu, unsigned long mflags, } } +static int kvm_arch_vcpu_yield_to(struct kvm_vcpu *target) +{ + struct kvmppc_vcore *vcore = target->arch.vcore; + + /* + * We expect to have been called by the real mode handler + * (kvmppc_rm_h_confer()) which would have directly returned + * H_SUCCESS if the source vcore wasn't idle (e.g. if it may + * have useful work to do and should not confer) so we don't + * recheck that here. + */ + + spin_lock(&vcore->lock); + if (target->arch.state == KVMPPC_VCPU_RUNNABLE && + vcore->vcore_state != VCORE_INACTIVE) + target = vcore->runner; + spin_unlock(&vcore->lock); + + return kvm_vcpu_yield_to(target); +} + +static int kvmppc_get_yield_count(struct kvm_vcpu *vcpu) +{ + int yield_count = 0; + struct lppaca *lppaca; + + spin_lock(&vcpu->arch.vpa_update_lock); + lppaca = (struct lppaca *)vcpu->arch.vpa.pinned_addr; + if (lppaca) + yield_count = lppaca->yield_count; + spin_unlock(&vcpu->arch.vpa_update_lock); + return yield_count; +} + int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu) { unsigned long req = kvmppc_get_gpr(vcpu, 3); unsigned long target, ret = H_SUCCESS; + int yield_count; struct kvm_vcpu *tvcpu; int idx, rc; @@ -646,7 +681,10 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu) ret = H_PARAMETER; break; } - kvm_vcpu_yield_to(tvcpu); + yield_count = kvmppc_get_gpr(vcpu, 5); + if (kvmppc_get_yield_count(tvcpu) != yield_count) + break; + kvm_arch_vcpu_yield_to(tvcpu); break; case H_REGISTER_VPA: ret = do_h_register_vpa(vcpu, kvmppc_get_gpr(vcpu, 4), @@ -1697,6 +1735,7 @@ static void kvmppc_run_core(struct kvmppc_vcore *vc) vc->vcore_state = VCORE_STARTING; vc->in_guest = 0; vc->napping_threads = 0; + vc->conferring_threads = 0; /* * Updating any of the vpas requires calling kvmppc_pin_guest_page, diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c index 1786bf80bf00..3e43f815ac5d 100644 --- a/arch/powerpc/kvm/book3s_hv_builtin.c +++ b/arch/powerpc/kvm/book3s_hv_builtin.c @@ -17,6 +17,7 @@ #include <linux/memblock.h> #include <linux/sizes.h> #include <linux/cma.h> +#include <linux/bitops.h> #include <asm/cputable.h> #include <asm/kvm_ppc.h> @@ -97,6 +98,37 @@ void __init kvm_cma_reserve(void) } /* + * Real-mode H_CONFER implementation. + * We check if we are the only vcpu out of this virtual core + * still running in the guest and not ceded. If so, we pop up + * to the virtual-mode implementation; if not, just return to + * the guest. + */ +long int kvmppc_rm_h_confer(struct kvm_vcpu *vcpu, int target, + unsigned int yield_count) +{ + struct kvmppc_vcore *vc = vcpu->arch.vcore; + int threads_running; + int threads_ceded; + int threads_conferring; + u64 stop = get_tb() + 10 * tb_ticks_per_usec; + int rv = H_SUCCESS; /* => don't yield */ + + set_bit(vcpu->arch.ptid, &vc->conferring_threads); + while ((get_tb() < stop) && (VCORE_EXIT_COUNT(vc) == 0)) { + threads_running = VCORE_ENTRY_COUNT(vc); + threads_ceded = hweight32(vc->napping_threads); + threads_conferring = hweight32(vc->conferring_threads); + if (threads_ceded + threads_conferring >= threads_running) { + rv = H_TOO_HARD; /* => do yield */ + break; + } + } + clear_bit(vcpu->arch.ptid, &vc->conferring_threads); + return rv; +} + +/* * When running HV mode KVM we need to block certain operations while KVM VMs * exist in the system. We use a counter of VMs to track this. * diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index 26a5b8d4dd3c..0a2d64fb5de8 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -1798,7 +1798,7 @@ hcall_real_table: .long 0 /* 0xd8 */ .long 0 /* 0xdc */ .long DOTSYM(kvmppc_h_cede) - hcall_real_table - .long 0 /* 0xe4 */ + .long DOTSYM(kvmppc_rm_h_confer) - hcall_real_table .long 0 /* 0xe8 */ .long 0 /* 0xec */ .long 0 /* 0xf0 */ |