[PATCH v2 4/4] KVM: x86: simplify kvm_apic_map
From: Radim KrÄmÃÅ
Date: Thu Feb 12 2015 - 13:42:33 EST
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 KrÄmÃÅ <rkrcmar@xxxxxxxxxx>
---
v2
- use different optimization to shorten apic_logical_id [Paolo]
- move apic_logical_id to lapic.c [Paolo]
- keep apic map validity check separate from apic_logical_id
(It can be done now as it's optimized in a different way.)
- rename apic_logical_id parameter from ldr to dest_id
(To avoid hinting that it has anything to do with real APIC.)
arch/x86/include/asm/kvm_host.h | 3 --
arch/x86/kvm/lapic.c | 75 ++++++++++++++---------------------------
arch/x86/kvm/lapic.h | 15 ---------
3 files changed, 25 insertions(+), 68 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 63a4e03fbdcf..c55dcaa5aead 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -557,9 +557,6 @@ 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 88e2bf3be235..3661f79642c9 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -141,6 +141,17 @@ 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)
+{
+ 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);
+
+ *cid = dest_id >> map->mode;
+ *lid = dest_id & ((1 << map->mode) - 1);
+}
+
static void recalculate_apic_map(struct kvm *kvm)
{
struct kvm_apic_map *new, *old = NULL;
@@ -154,49 +165,6 @@ 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;
@@ -204,15 +172,25 @@ 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;
}
@@ -729,7 +707,6 @@ 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)) {
@@ -737,15 +714,13 @@ 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 0bc6c656625b..8ba09b338682 100644
--- 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;
--
2.3.0
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