diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h index 1f345a0b6ba20b24b5408f21099fb10f68e9ff82..83a9aa3cf689172648d234da87ec7d4e95add69d 100644 --- a/arch/powerpc/include/asm/kvm_book3s.h +++ b/arch/powerpc/include/asm/kvm_book3s.h @@ -390,4 +390,51 @@ extern int kvmppc_h_logical_ci_store(struct kvm_vcpu *vcpu); #define SPLIT_HACK_MASK 0xff000000 #define SPLIT_HACK_OFFS 0xfb000000 +/* + * This packs a VCPU ID from the [0..KVM_MAX_VCPU_ID) space down to the + * [0..KVM_MAX_VCPUS) space, using knowledge of the guest's core stride + * (but not its actual threading mode, which is not available) to avoid + * collisions. + * + * The implementation leaves VCPU IDs from the range [0..KVM_MAX_VCPUS) (block + * 0) unchanged: if the guest is filling each VCORE completely then it will be + * using consecutive IDs and it will fill the space without any packing. + * + * For higher VCPU IDs, the packed ID is based on the VCPU ID modulo + * KVM_MAX_VCPUS (effectively masking off the top bits) and then an offset is + * added to avoid collisions. + * + * VCPU IDs in the range [KVM_MAX_VCPUS..(KVM_MAX_VCPUS*2)) (block 1) are only + * possible if the guest is leaving at least 1/2 of each VCORE empty, so IDs + * can be safely packed into the second half of each VCORE by adding an offset + * of (stride / 2). + * + * Similarly, if VCPU IDs in the range [(KVM_MAX_VCPUS*2)..(KVM_MAX_VCPUS*4)) + * (blocks 2 and 3) are seen, the guest must be leaving at least 3/4 of each + * VCORE empty so packed IDs can be offset by (stride / 4) and (stride * 3 / 4). + * + * Finally, VCPU IDs from blocks 5..7 will only be seen if the guest is using a + * stride of 8 and 1 thread per core so the remaining offsets of 1, 5, 3 and 7 + * must be free to use. + * + * (The offsets for each block are stored in block_offsets[], indexed by the + * block number if the stride is 8. For cases where the guest's stride is less + * than 8, we can re-use the block_offsets array by multiplying the block + * number by (MAX_SMT_THREADS / stride) to reach the correct entry.) + */ +static inline u32 kvmppc_pack_vcpu_id(struct kvm *kvm, u32 id) +{ + const int block_offsets[MAX_SMT_THREADS] = {0, 4, 2, 6, 1, 5, 3, 7}; + int stride = kvm->arch.emul_smt_mode; + int block = (id / KVM_MAX_VCPUS) * (MAX_SMT_THREADS / stride); + u32 packed_id; + + if (WARN_ONCE(block >= MAX_SMT_THREADS, "VCPU ID too large to pack")) + return 0; + packed_id = (id % KVM_MAX_VCPUS) + block_offsets[block]; + if (WARN_ONCE(packed_id >= KVM_MAX_VCPUS, "VCPU ID packing failed")) + return 0; + return packed_id; +} + #endif /* __ASM_KVM_BOOK3S_H__ */ diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index d73b29b6aaa139dcd7d34b8be3a73b1f8a7eeea8..785245e09f3213aea006891036068fa5dd2a1eac 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -1816,7 +1816,7 @@ static int threads_per_vcore(struct kvm *kvm) return threads_per_subcore; } -static struct kvmppc_vcore *kvmppc_vcore_create(struct kvm *kvm, int core) +static struct kvmppc_vcore *kvmppc_vcore_create(struct kvm *kvm, int id) { struct kvmppc_vcore *vcore; @@ -1830,7 +1830,7 @@ static struct kvmppc_vcore *kvmppc_vcore_create(struct kvm *kvm, int core) init_swait_queue_head(&vcore->wq); vcore->preempt_tb = TB_NIL; vcore->lpcr = kvm->arch.lpcr; - vcore->first_vcpuid = core * kvm->arch.smt_mode; + vcore->first_vcpuid = id; vcore->kvm = kvm; INIT_LIST_HEAD(&vcore->preempt_list); @@ -1989,10 +1989,16 @@ static struct kvm_vcpu *kvmppc_core_vcpu_create_hv(struct kvm *kvm, unsigned int id) { struct kvm_vcpu *vcpu; - int err; + int err = -EINVAL; int core; struct kvmppc_vcore *vcore; + if (id >= (KVM_MAX_VCPUS * kvm->arch.emul_smt_mode) && + cpu_has_feature(CPU_FTR_ARCH_300)) { + pr_devel("DNCI: VCPU ID too high\n"); + goto out; + } + err = -ENOMEM; vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL); if (!vcpu) @@ -2048,12 +2054,21 @@ static struct kvm_vcpu *kvmppc_core_vcpu_create_hv(struct kvm *kvm, mutex_lock(&kvm->lock); vcore = NULL; err = -EINVAL; - core = id / kvm->arch.smt_mode; + if (cpu_has_feature(CPU_FTR_ARCH_300)) { + BUG_ON(kvm->arch.smt_mode != 1); + core = kvmppc_pack_vcpu_id(kvm, id); + } else { + core = id / kvm->arch.smt_mode; + } if (core < KVM_MAX_VCORES) { vcore = kvm->arch.vcores[core]; - if (!vcore) { + if (vcore && cpu_has_feature(CPU_FTR_ARCH_300)) { + pr_devel("KVM: collision on id %u", id); + vcore = NULL; + } else if (!vcore) { err = -ENOMEM; - vcore = kvmppc_vcore_create(kvm, core); + vcore = kvmppc_vcore_create(kvm, + id & ~(kvm->arch.smt_mode - 1)); kvm->arch.vcores[core] = vcore; kvm->arch.online_vcores++; } diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c index f9818d7d3381d8c072605534202fb6c91b7d58e4..126f02b3ffb8271e0cac825e13ecf5146de0afe8 100644 --- a/arch/powerpc/kvm/book3s_xive.c +++ b/arch/powerpc/kvm/book3s_xive.c @@ -317,6 +317,11 @@ static int xive_select_target(struct kvm *kvm, u32 *server, u8 prio) return -EBUSY; } +static u32 xive_vp(struct kvmppc_xive *xive, u32 server) +{ + return xive->vp_base + kvmppc_pack_vcpu_id(xive->kvm, server); +} + static u8 xive_lock_and_mask(struct kvmppc_xive *xive, struct kvmppc_xive_src_block *sb, struct kvmppc_xive_irq_state *state) @@ -362,7 +367,7 @@ static u8 xive_lock_and_mask(struct kvmppc_xive *xive, */ if (xd->flags & OPAL_XIVE_IRQ_MASK_VIA_FW) { xive_native_configure_irq(hw_num, - xive->vp_base + state->act_server, + xive_vp(xive, state->act_server), MASKED, state->number); /* set old_p so we can track if an H_EOI was done */ state->old_p = true; @@ -418,7 +423,7 @@ static void xive_finish_unmask(struct kvmppc_xive *xive, */ if (xd->flags & OPAL_XIVE_IRQ_MASK_VIA_FW) { xive_native_configure_irq(hw_num, - xive->vp_base + state->act_server, + xive_vp(xive, state->act_server), state->act_priority, state->number); /* If an EOI is needed, do it here */ if (!state->old_p) @@ -495,7 +500,7 @@ static int xive_target_interrupt(struct kvm *kvm, kvmppc_xive_select_irq(state, &hw_num, NULL); return xive_native_configure_irq(hw_num, - xive->vp_base + server, + xive_vp(xive, server), prio, state->number); } @@ -883,7 +888,7 @@ int kvmppc_xive_set_mapped(struct kvm *kvm, unsigned long guest_irq, * which is fine for a never started interrupt. */ xive_native_configure_irq(hw_irq, - xive->vp_base + state->act_server, + xive_vp(xive, state->act_server), state->act_priority, state->number); /* @@ -959,7 +964,7 @@ int kvmppc_xive_clr_mapped(struct kvm *kvm, unsigned long guest_irq, /* Reconfigure the IPI */ xive_native_configure_irq(state->ipi_number, - xive->vp_base + state->act_server, + xive_vp(xive, state->act_server), state->act_priority, state->number); /* @@ -1084,7 +1089,7 @@ int kvmppc_xive_connect_vcpu(struct kvm_device *dev, pr_devel("Duplicate !\n"); return -EEXIST; } - if (cpu >= KVM_MAX_VCPUS) { + if (cpu >= (KVM_MAX_VCPUS * vcpu->kvm->arch.emul_smt_mode)) { pr_devel("Out of bounds !\n"); return -EINVAL; } @@ -1098,7 +1103,7 @@ int kvmppc_xive_connect_vcpu(struct kvm_device *dev, xc->xive = xive; xc->vcpu = vcpu; xc->server_num = cpu; - xc->vp_id = xive->vp_base + cpu; + xc->vp_id = xive_vp(xive, cpu); xc->mfrr = 0xff; xc->valid = true;