Logical x2APIC IDs map injectively to physical x2APIC IDs, so we can
reuse the physical array for them. This allows us to save space by
separating logical xAPIC maps.
Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 6 ++--
arch/x86/kvm/lapic.c | 69 +++++++++++++++++++++--------------------
2 files changed, 39 insertions(+), 36 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 53d39771842b..3194b19b9c7b 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -683,8 +683,10 @@ struct kvm_apic_map {
struct rcu_head rcu;
u8 mode;
struct kvm_lapic *phys_map[256];
- /* first index is cluster id second is cpu id in a cluster */
- struct kvm_lapic *logical_map[16][16];
+ union {
+ struct kvm_lapic *xapic_flat_map[8];
+ struct kvm_lapic *xapic_cluster_map[16][4];
+ };
};
/* Hyper-V emulation context */
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 2987843657db..9880d03f533d 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -115,26 +115,36 @@ static inline int apic_enabled(struct kvm_lapic *apic)
(LVT_MASK | APIC_MODE_MASK | APIC_INPUT_POLARITY | \
APIC_LVT_REMOTE_IRR | APIC_LVT_LEVEL_TRIGGER)
-/* 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 inline bool kvm_apic_map_get_logical_dest(struct kvm_apic_map *map,
+ u32 dest_id, struct kvm_lapic ***cluster, u16 *mask) {
+ switch (map->mode) {
+ case KVM_APIC_MODE_X2APIC: {
+ u32 offset = (dest_id >> 16) * 16;
+ u32 max_apic_id = ARRAY_SIZE(map->phys_map) - 1;
-static inline void
-apic_logical_id(struct kvm_apic_map *map, u32 dest_id, u16 *cid, u16 *lid)
-{
- unsigned lid_bits;
+ if (offset <= max_apic_id) {
+ u8 cluster_size = min(max_apic_id - offset + 1, 16U);
- BUILD_BUG_ON(KVM_APIC_MODE_XAPIC_CLUSTER != 4);
- BUILD_BUG_ON(KVM_APIC_MODE_XAPIC_FLAT != 8);
- BUILD_BUG_ON(KVM_APIC_MODE_X2APIC != 16);
- lid_bits = map->mode;
+ *cluster = &map->phys_map[offset];
+ *mask = dest_id & (0xffff >> (16 - cluster_size));
+ } else {
+ *mask = 0;
+ }
- *cid = dest_id >> lid_bits;
- *lid = dest_id & ((1 << lid_bits) - 1);
+ return true;
+ }
+ case KVM_APIC_MODE_XAPIC_FLAT:
+ *cluster = map->xapic_flat_map;
+ *mask = dest_id & 0xff;
+ return true;
+ case KVM_APIC_MODE_XAPIC_CLUSTER:
+ *cluster = map->xapic_cluster_map[dest_id >> 4];
+ *mask = dest_id & 0xf;
+ return true;
+ default:
+ /* Not optimized. */
+ return false;
+ }
}
static void recalculate_apic_map(struct kvm *kvm)
@@ -152,7 +162,8 @@ static void recalculate_apic_map(struct kvm *kvm)
kvm_for_each_vcpu(i, vcpu, kvm) {
struct kvm_lapic *apic = vcpu->arch.apic;
- u16 cid, lid;
+ struct kvm_lapic **cluster;
+ u16 mask;
u32 ldr, aid;
if (!kvm_apic_present(vcpu))
@@ -174,13 +185,11 @@ static void recalculate_apic_map(struct kvm *kvm)
new->mode |= KVM_APIC_MODE_XAPIC_CLUSTER;
}
- if (!kvm_apic_logical_map_valid(new))
+ if (!kvm_apic_map_get_logical_dest(new, ldr, &cluster, &mask))
continue;
- apic_logical_id(new, ldr, &cid, &lid);
-
- if (lid && cid < ARRAY_SIZE(new->logical_map))
- new->logical_map[cid][ffs(lid) - 1] = apic;
+ if (mask)
+ cluster[ffs(mask) - 1] = apic;
}
out:
old = rcu_dereference_protected(kvm->arch.apic_map,
@@ -685,7 +694,6 @@ static inline bool kvm_apic_map_get_dest_lapic(struct kvm *kvm,
{
int i, lowest;
bool x2apic_ipi;
- u16 cid;
if (irq->shorthand == APIC_DEST_SELF && src) {
*dst = src;
@@ -711,18 +719,11 @@ static inline bool kvm_apic_map_get_dest_lapic(struct kvm *kvm,
return true;
}
- if (!kvm_apic_logical_map_valid(map))
+ *bitmap = 0;
+ if (!kvm_apic_map_get_logical_dest(map, irq->dest_id, dst,
+ (u16 *)bitmap))
return false;
- apic_logical_id(map, irq->dest_id, &cid, (u16 *)bitmap);
-
- if (cid >= ARRAY_SIZE(map->logical_map)) {
- *bitmap = 0;
- return true;
- }
-
- *dst = map->logical_map[cid];
-
if (!kvm_lowest_prio_delivery(irq))
return true;
--
2.9.0
--
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