diff options
Diffstat (limited to 'arch/powerpc/kvm/book3s_hv.c')
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv.c | 133 |
1 files changed, 125 insertions, 8 deletions
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 2b4484d07971..8ecf226084af 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -46,6 +46,8 @@ #include <linux/of.h> #include <asm/reg.h> +#include <asm/ppc-opcode.h> +#include <asm/disassemble.h> #include <asm/cputable.h> #include <asm/cacheflush.h> #include <asm/tlbflush.h> @@ -681,6 +683,15 @@ static bool kvmppc_doorbell_pending(struct kvm_vcpu *vcpu) int thr; struct kvmppc_vcore *vc; + if (vcpu->arch.doorbell_request) + return true; + /* + * Ensure that the read of vcore->dpdes comes after the read + * of vcpu->doorbell_request. This barrier matches the + * lwsync in book3s_hv_rmhandlers.S just before the + * fast_guest_return label. + */ + smp_rmb(); vc = vcpu->arch.vcore; thr = vcpu->vcpu_id - vc->first_vcpuid; return !!(vc->dpdes & (1 << thr)); @@ -937,6 +948,101 @@ static int kvmppc_emulate_debug_inst(struct kvm_run *run, } } +static void do_nothing(void *x) +{ +} + +static unsigned long kvmppc_read_dpdes(struct kvm_vcpu *vcpu) +{ + int thr, cpu, pcpu, nthreads; + struct kvm_vcpu *v; + unsigned long dpdes; + + nthreads = vcpu->kvm->arch.emul_smt_mode; + dpdes = 0; + cpu = vcpu->vcpu_id & ~(nthreads - 1); + for (thr = 0; thr < nthreads; ++thr, ++cpu) { + v = kvmppc_find_vcpu(vcpu->kvm, cpu); + if (!v) + continue; + /* + * If the vcpu is currently running on a physical cpu thread, + * interrupt it in order to pull it out of the guest briefly, + * which will update its vcore->dpdes value. + */ + pcpu = READ_ONCE(v->cpu); + if (pcpu >= 0) + smp_call_function_single(pcpu, do_nothing, NULL, 1); + if (kvmppc_doorbell_pending(v)) + dpdes |= 1 << thr; + } + return dpdes; +} + +/* + * On POWER9, emulate doorbell-related instructions in order to + * give the guest the illusion of running on a multi-threaded core. + * The instructions emulated are msgsndp, msgclrp, mfspr TIR, + * and mfspr DPDES. + */ +static int kvmppc_emulate_doorbell_instr(struct kvm_vcpu *vcpu) +{ + u32 inst, rb, thr; + unsigned long arg; + struct kvm *kvm = vcpu->kvm; + struct kvm_vcpu *tvcpu; + + if (!cpu_has_feature(CPU_FTR_ARCH_300)) + return EMULATE_FAIL; + if (kvmppc_get_last_inst(vcpu, INST_GENERIC, &inst) != EMULATE_DONE) + return RESUME_GUEST; + if (get_op(inst) != 31) + return EMULATE_FAIL; + rb = get_rb(inst); + thr = vcpu->vcpu_id & (kvm->arch.emul_smt_mode - 1); + switch (get_xop(inst)) { + case OP_31_XOP_MSGSNDP: + arg = kvmppc_get_gpr(vcpu, rb); + if (((arg >> 27) & 0xf) != PPC_DBELL_SERVER) + break; + arg &= 0x3f; + if (arg >= kvm->arch.emul_smt_mode) + break; + tvcpu = kvmppc_find_vcpu(kvm, vcpu->vcpu_id - thr + arg); + if (!tvcpu) + break; + if (!tvcpu->arch.doorbell_request) { + tvcpu->arch.doorbell_request = 1; + kvmppc_fast_vcpu_kick_hv(tvcpu); + } + break; + case OP_31_XOP_MSGCLRP: + arg = kvmppc_get_gpr(vcpu, rb); + if (((arg >> 27) & 0xf) != PPC_DBELL_SERVER) + break; + vcpu->arch.vcore->dpdes = 0; + vcpu->arch.doorbell_request = 0; + break; + case OP_31_XOP_MFSPR: + switch (get_sprn(inst)) { + case SPRN_TIR: + arg = thr; + break; + case SPRN_DPDES: + arg = kvmppc_read_dpdes(vcpu); + break; + default: + return EMULATE_FAIL; + } + kvmppc_set_gpr(vcpu, get_rt(inst), arg); + break; + default: + return EMULATE_FAIL; + } + kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4); + return RESUME_GUEST; +} + static int kvmppc_handle_exit_hv(struct kvm_run *run, struct kvm_vcpu *vcpu, struct task_struct *tsk) { @@ -1059,12 +1165,19 @@ static int kvmppc_handle_exit_hv(struct kvm_run *run, struct kvm_vcpu *vcpu, break; /* * This occurs if the guest (kernel or userspace), does something that - * is prohibited by HFSCR. We just generate a program interrupt to - * the guest. + * is prohibited by HFSCR. + * On POWER9, this could be a doorbell instruction that we need + * to emulate. + * Otherwise, we just generate a program interrupt to the guest. */ case BOOK3S_INTERRUPT_H_FAC_UNAVAIL: - kvmppc_core_queue_program(vcpu, SRR1_PROGILL); - r = RESUME_GUEST; + r = EMULATE_FAIL; + if ((vcpu->arch.hfscr >> 56) == FSCR_MSGP_LG) + r = kvmppc_emulate_doorbell_instr(vcpu); + if (r == EMULATE_FAIL) { + kvmppc_core_queue_program(vcpu, SRR1_PROGILL); + r = RESUME_GUEST; + } break; case BOOK3S_INTERRUPT_HV_RM_HARD: r = RESUME_PASSTHROUGH; @@ -1826,10 +1939,14 @@ static struct kvm_vcpu *kvmppc_core_vcpu_create_hv(struct kvm *kvm, * This value is only used on POWER9. * On POWER9 DD1, TM doesn't work, so we make sure to * prevent the guest from using it. + * On POWER9, we want to virtualize the doorbell facility, so we + * turn off the HFSCR bit, which causes those instructions to trap. */ vcpu->arch.hfscr = mfspr(SPRN_HFSCR); if (!cpu_has_feature(CPU_FTR_TM)) vcpu->arch.hfscr &= ~HFSCR_TM; + if (cpu_has_feature(CPU_FTR_ARCH_300)) + vcpu->arch.hfscr &= ~HFSCR_MSGP; kvmppc_mmu_book3s_hv_init(vcpu); @@ -1880,6 +1997,7 @@ static int kvmhv_set_smt_mode(struct kvm *kvm, unsigned long smt_mode, unsigned long flags) { int err; + int esmt = 0; if (flags) return -EINVAL; @@ -1897,12 +2015,14 @@ static int kvmhv_set_smt_mode(struct kvm *kvm, unsigned long smt_mode, * On POWER9, the threading mode is "loose", * so each vcpu gets its own vcore. */ + esmt = smt_mode; smt_mode = 1; } mutex_lock(&kvm->lock); err = -EBUSY; if (!kvm->arch.online_vcores) { kvm->arch.smt_mode = smt_mode; + kvm->arch.emul_smt_mode = esmt; err = 0; } mutex_unlock(&kvm->lock); @@ -2025,10 +2145,6 @@ static void kvmppc_release_hwthread(int cpu) tpaca->kvm_hstate.kvm_split_mode = NULL; } -static void do_nothing(void *x) -{ -} - static void radix_flush_cpu(struct kvm *kvm, int cpu, struct kvm_vcpu *vcpu) { int i; @@ -3600,6 +3716,7 @@ static int kvmppc_core_init_vm_hv(struct kvm *kvm) kvm->arch.smt_mode = threads_per_subcore; else kvm->arch.smt_mode = 1; + kvm->arch.emul_smt_mode = 1; /* * Create a debugfs directory for the VM |