KVM: x86: simplify kvm_apic_map

recalculate_apic_map() uses two passes over all VCPUs.  This is a relic
from time when we selected a global mode in the first pass and set up
the optimized table in the second pass (to have a consistent mode).

Recent changes made mixed mode unoptimized and we can do it in one pass.
Format of logical MDA is a function of the mode, so we encode it in
apic_logical_id() and drop obsoleted variables from the struct.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Message-Id: <1423766494-26150-5-git-send-email-rkrcmar@redhat.com>
[Add lid_bits temporary in apic_logical_id. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 9477b27e8e1e03a395c4de5d412b085bec17175d..d0cfdb08b4c25cd38c57ee976ad2fbbe13c4f9c7 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -562,9 +562,6 @@ struct kvm_arch_memory_slot {
 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;
        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];

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index fa4bd89ea381adc7287e34d9a15f08a9f29d53d8..11a0af113f275f7ef35dbec4581b3e748a37e853 100644 (file)
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -141,6 +141,20 @@ static inline bool kvm_apic_logical_map_valid(struct kvm_apic_map *map)
        return !(map->mode & (map->mode - 1));
 }
 
+static inline void
+apic_logical_id(struct kvm_apic_map *map, u32 dest_id, u16 *cid, u16 *lid)
+{
+       unsigned lid_bits;
+
+       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;
+
+       *cid = dest_id >> lid_bits;
+       *lid = dest_id & ((1 << lid_bits) - 1);
+}
+
 static void recalculate_apic_map(struct kvm *kvm)
 {
        struct kvm_apic_map *new, *old = NULL;
@@ -154,49 +168,6 @@ static void recalculate_apic_map(struct kvm *kvm)
        if (!new)
                goto out;
 
-       new->ldr_bits = 8;
-       /* flat mode is default */
-       new->cid_shift = 8;
-       new->cid_mask = 0;
-       new->lid_mask = 0xff;
-
-       kvm_for_each_vcpu(i, vcpu, kvm) {
-               struct kvm_lapic *apic = vcpu->arch.apic;
-
-               if (!kvm_apic_present(vcpu))
-                       continue;
-
-               if (apic_x2apic_mode(apic)) {
-                       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;
-                       }
-               }
-
-               /*
-                * All APICs have to be configured in the same mode by an OS.
-                * We take advatage of this while building logical id loockup
-                * table. After reset APICs are in software disabled mode, so if
-                * we find apic with different setting we assume this is the mode
-                * OS wants all apics to be in; build lookup table accordingly.
-                */
-               if (kvm_apic_sw_enabled(apic))
-                       break;
-       }
-
        kvm_for_each_vcpu(i, vcpu, kvm) {
                struct kvm_lapic *apic = vcpu->arch.apic;
                u16 cid, lid;
@@ -207,15 +178,25 @@ static void recalculate_apic_map(struct kvm *kvm)
 
                aid = kvm_apic_id(apic);
                ldr = kvm_apic_get_reg(apic, APIC_LDR);
-               cid = apic_cluster_id(new, ldr);
-               lid = apic_logical_id(new, ldr);
 
                if (aid < ARRAY_SIZE(new->phys_map))
                        new->phys_map[aid] = apic;
 
-               if (!kvm_apic_logical_map_valid(new));
+               if (apic_x2apic_mode(apic)) {
+                       new->mode |= KVM_APIC_MODE_X2APIC;
+               } else if (ldr) {
+                       ldr = GET_APIC_LOGICAL_ID(ldr);
+                       if (kvm_apic_get_reg(apic, APIC_DFR) == APIC_DFR_FLAT)
+                               new->mode |= KVM_APIC_MODE_XAPIC_FLAT;
+                       else
+                               new->mode |= KVM_APIC_MODE_XAPIC_CLUSTER;
+               }
+
+               if (!kvm_apic_logical_map_valid(new))
                        continue;
 
+               apic_logical_id(new, ldr, &cid, &lid);
+
                if (lid && cid < ARRAY_SIZE(new->logical_map))
                        new->logical_map[cid][ffs(lid) - 1] = apic;
        }
@@ -732,7 +713,6 @@ 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;
 
                if (!kvm_apic_logical_map_valid(map)) {
@@ -740,15 +720,13 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
                        goto out;
                }
 
-               cid = apic_cluster_id(map, mda);
+               apic_logical_id(map, irq->dest_id, &cid, (u16 *)&bitmap);
 
                if (cid >= ARRAY_SIZE(map->logical_map))
                        goto out;
 
                dst = map->logical_map[cid];
 
-               bitmap = apic_logical_id(map, mda);
-
                if (irq->delivery_mode == APIC_DM_LOWEST) {
                        int l = -1;
                        for_each_set_bit(i, &bitmap, 16) {

diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index e284c2880c566ebbf8890200d01b78935d20ab8a..9d28383fc1e70cc3437ae2eb062ff9433c659f96 100644 (file)
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -148,21 +148,6 @@ static inline bool kvm_apic_vid_enabled(struct kvm *kvm)
        return kvm_x86_ops->vm_has_apicv(kvm);
 }
 
-static inline u16 apic_cluster_id(struct kvm_apic_map *map, u32 ldr)
-{
-       u16 cid;
-       ldr >>= 32 - map->ldr_bits;
-       cid = (ldr >> map->cid_shift) & map->cid_mask;
-
-       return cid;
-}
-
-static inline u16 apic_logical_id(struct kvm_apic_map *map, u32 ldr)
-{
-       ldr >>= (32 - map->ldr_bits);
-       return ldr & map->lid_mask;
-}
-
 static inline bool kvm_apic_has_events(struct kvm_vcpu *vcpu)
 {
        return vcpu->arch.apic->pending_events;