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| author | Radim Krčmář <rkrcmar@redhat.com> | 2016-07-12 22:09:20 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2016-07-14 09:03:53 +0200 |
| commit | 0ca52e7b81a37260c7edb823c8ac6a49c6280b5e (patch) | |
| tree | 6116f41d00673db8be0280dfca84dfb274da8096 /arch/x86 | |
| parent | e45115b62f9abb143a03036dbde05faf5864aa01 (diff) | |
| download | linux-0ca52e7b81a37260c7edb823c8ac6a49c6280b5e.tar.gz linux-0ca52e7b81a37260c7edb823c8ac6a49c6280b5e.tar.bz2 linux-0ca52e7b81a37260c7edb823c8ac6a49c6280b5e.zip | |
KVM: x86: dynamic kvm_apic_map
x2APIC supports up to 2^32-1 LAPICs, but most guest in coming years will
probably has fewer VCPUs. Dynamic size saves memory at the cost of
turning one constant into a variable.
apic_map mutex had to be moved before allocation to avoid races with cpu
hotplug.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 3 | ||||
| -rw-r--r-- | arch/x86/kvm/lapic.c | 18 | ||||
| -rw-r--r-- | arch/x86/kvm/lapic.h | 2 |
3 files changed, 16 insertions, 7 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 623089c4e1a7..a2832cc3cb81 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -682,11 +682,12 @@ struct kvm_arch_memory_slot { struct kvm_apic_map { struct rcu_head rcu; u8 mode; - struct kvm_lapic *phys_map[256]; + u32 max_apic_id; union { struct kvm_lapic *xapic_flat_map[8]; struct kvm_lapic *xapic_cluster_map[16][4]; }; + struct kvm_lapic *phys_map[]; }; /* Hyper-V emulation context */ diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 9880d03f533d..224fc1c5fcc6 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -120,7 +120,7 @@ static inline bool kvm_apic_map_get_logical_dest(struct kvm_apic_map *map, switch (map->mode) { case KVM_APIC_MODE_X2APIC: { u32 offset = (dest_id >> 16) * 16; - u32 max_apic_id = ARRAY_SIZE(map->phys_map) - 1; + u32 max_apic_id = map->max_apic_id; if (offset <= max_apic_id) { u8 cluster_size = min(max_apic_id - offset + 1, 16U); @@ -152,14 +152,22 @@ static void recalculate_apic_map(struct kvm *kvm) struct kvm_apic_map *new, *old = NULL; struct kvm_vcpu *vcpu; int i; - - new = kzalloc(sizeof(struct kvm_apic_map), GFP_KERNEL); + u32 max_id = 255; mutex_lock(&kvm->arch.apic_map_lock); + kvm_for_each_vcpu(i, vcpu, kvm) + if (kvm_apic_present(vcpu)) + max_id = max(max_id, kvm_apic_id(vcpu->arch.apic)); + + new = kzalloc(sizeof(struct kvm_apic_map) + + sizeof(struct kvm_lapic *) * (max_id + 1), GFP_KERNEL); + if (!new) goto out; + new->max_apic_id = max_id; + kvm_for_each_vcpu(i, vcpu, kvm) { struct kvm_lapic *apic = vcpu->arch.apic; struct kvm_lapic **cluster; @@ -172,7 +180,7 @@ static void recalculate_apic_map(struct kvm *kvm) aid = kvm_apic_id(apic); ldr = kvm_lapic_get_reg(apic, APIC_LDR); - if (aid < ARRAY_SIZE(new->phys_map)) + if (aid <= new->max_apic_id) new->phys_map[aid] = apic; if (apic_x2apic_mode(apic)) { @@ -710,7 +718,7 @@ static inline bool kvm_apic_map_get_dest_lapic(struct kvm *kvm, return false; if (irq->dest_mode == APIC_DEST_PHYSICAL) { - if (irq->dest_id >= ARRAY_SIZE(map->phys_map)) { + if (irq->dest_id > map->max_apic_id) { *bitmap = 0; } else { *dst = &map->phys_map[irq->dest_id]; diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h index 336ba51bb16e..8d811139d2b3 100644 --- a/arch/x86/kvm/lapic.h +++ b/arch/x86/kvm/lapic.h @@ -200,7 +200,7 @@ static inline int kvm_lapic_latched_init(struct kvm_vcpu *vcpu) return lapic_in_kernel(vcpu) && test_bit(KVM_APIC_INIT, &vcpu->arch.apic->pending_events); } -static inline int kvm_apic_id(struct kvm_lapic *apic) +static inline u32 kvm_apic_id(struct kvm_lapic *apic) { return (kvm_lapic_get_reg(apic, APIC_ID) >> 24) & 0xff; } |