diff options
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 12 | ||||
| -rw-r--r-- | arch/x86/kvm/lapic.c | 24 |
2 files changed, 35 insertions, 1 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 5b1bc97a258a..9477b27e8e1e 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -548,8 +548,20 @@ struct kvm_arch_memory_slot { struct kvm_lpage_info *lpage_info[KVM_NR_PAGE_SIZES - 1]; }; +/* + * We use as the mode the number of bits allocated in the LDR for the + * logical processor ID. It happens that these are all powers of two. + * This makes it is very easy to detect cases where the APICs are + * configured for multiple modes; in that case, we cannot use the map and + * hence cannot use kvm_irq_delivery_to_apic_fast either. + */ +#define KVM_APIC_MODE_XAPIC_CLUSTER 4 +#define KVM_APIC_MODE_XAPIC_FLAT 8 +#define KVM_APIC_MODE_X2APIC 16 + struct kvm_apic_map { struct rcu_head rcu; + u8 mode; u8 ldr_bits; /* fields bellow are used to decode ldr values in different modes */ u32 cid_shift, cid_mask, lid_mask; diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index d45f00ba7440..fa4bd89ea381 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -133,6 +133,14 @@ static inline int kvm_apic_id(struct kvm_lapic *apic) return (kvm_apic_get_reg(apic, APIC_ID) >> 24) & 0xff; } +/* The logical map is definitely wrong if we have multiple + * modes at the same time. (Physical map is always right.) + */ +static inline bool kvm_apic_logical_map_valid(struct kvm_apic_map *map) +{ + return !(map->mode & (map->mode - 1)); +} + static void recalculate_apic_map(struct kvm *kvm) { struct kvm_apic_map *new, *old = NULL; @@ -162,16 +170,19 @@ static void recalculate_apic_map(struct kvm *kvm) new->ldr_bits = 32; new->cid_shift = 16; new->cid_mask = new->lid_mask = 0xffff; + new->mode |= KVM_APIC_MODE_X2APIC; } else if (kvm_apic_get_reg(apic, APIC_LDR)) { if (kvm_apic_get_reg(apic, APIC_DFR) == APIC_DFR_CLUSTER) { new->cid_shift = 4; new->cid_mask = 0xf; new->lid_mask = 0xf; + new->mode |= KVM_APIC_MODE_XAPIC_CLUSTER; } else { new->cid_shift = 8; new->cid_mask = 0; new->lid_mask = 0xff; + new->mode |= KVM_APIC_MODE_XAPIC_FLAT; } } @@ -201,6 +212,10 @@ static void recalculate_apic_map(struct kvm *kvm) if (aid < ARRAY_SIZE(new->phys_map)) new->phys_map[aid] = apic; + + if (!kvm_apic_logical_map_valid(new)); + continue; + if (lid && cid < ARRAY_SIZE(new->logical_map)) new->logical_map[cid][ffs(lid) - 1] = apic; } @@ -718,7 +733,14 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src, dst = &map->phys_map[irq->dest_id]; } else { u32 mda = irq->dest_id << (32 - map->ldr_bits); - u16 cid = apic_cluster_id(map, mda); + u16 cid; + + if (!kvm_apic_logical_map_valid(map)) { + ret = false; + goto out; + } + + cid = apic_cluster_id(map, mda); if (cid >= ARRAY_SIZE(map->logical_map)) goto out; |