From: "Radim Krčmář" <rkrcmar@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
"Lan, Tianyu" <tianyu.lan@intel.com>,
Igor Mammedov <imammedo@redhat.com>,
Jan Kiszka <jan.kiszka@web.de>, Peter Xu <peterx@redhat.com>,
Yang Zhang <yang.zhang.wz@gmail.com>
Subject: [PATCH v3 04/14] KVM: x86: dynamic kvm_apic_map
Date: Tue, 12 Jul 2016 22:09:20 +0200 [thread overview]
Message-ID: <20160712200930.32143-5-rkrcmar@redhat.com> (raw)
In-Reply-To: <20160712200930.32143-1-rkrcmar@redhat.com>
x2APIC supports up to 2^32-1 LAPICs, but most guest in coming years will
have slighly less 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>
---
arch/x86/include/asm/kvm_host.h | 3 ++-
arch/x86/kvm/lapic.c | 18 +++++++++++++-----
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 3194b19b9c7b..643e3dffcd85 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;
}
--
2.9.0
next prev parent reply other threads:[~2016-07-12 20:10 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-12 20:09 [PATCH v3 00/14] KVM: x86: break the xAPIC barrier Radim Krčmář
2016-07-12 20:09 ` [PATCH v3 01/14] KVM: x86: bump KVM_SOFT_MAX_VCPUS to 240 Radim Krčmář
2016-07-12 20:09 ` [PATCH v3 02/14] KVM: x86: add kvm_apic_map_get_dest_lapic Radim Krčmář
2016-07-12 20:09 ` [PATCH v3 03/14] KVM: x86: use physical LAPIC array for logical x2APIC Radim Krčmář
2016-08-02 13:46 ` Wanpeng Li
2016-08-02 14:22 ` Radim Krčmář
2016-08-02 16:40 ` Nadav Amit
2016-07-12 20:09 ` Radim Krčmář [this message]
2016-07-13 8:29 ` [PATCH v3 04/14] KVM: x86: dynamic kvm_apic_map Paolo Bonzini
2016-07-13 14:37 ` Radim Krčmář
2016-08-02 11:39 ` Wanpeng Li
2016-08-02 12:22 ` Radim Krčmář
2016-08-02 13:15 ` Wanpeng Li
2016-07-12 20:09 ` [PATCH v3 05/14] KVM: x86: use generic function for MSI parsing Radim Krčmář
2016-07-12 20:09 ` [PATCH v3 06/14] KVM: x86: use hardware-compatible format for APIC ID register Radim Krčmář
2016-07-12 20:09 ` [PATCH v3 07/14] KVM: x86: reset APIC ID when enabling LAPIC Radim Krčmář
2016-08-02 13:26 ` Wanpeng Li
2016-08-02 13:52 ` Radim Krčmář
2016-07-12 20:09 ` [PATCH v3 08/14] KVM: VMX: optimize APIC ID read with APICv Radim Krčmář
2016-07-12 20:09 ` [PATCH v3 09/14] KVM: x86: reset lapic base in kvm_lapic_reset Radim Krčmář
2016-07-12 20:09 ` [PATCH v3 10/14] KVM: pass struct kvm to kvm_set_routing_entry Radim Krčmář
2016-07-12 20:09 ` [PATCH v3 11/14] KVM: x86: add KVM_CAP_X2APIC_API Radim Krčmář
2016-07-13 8:41 ` Paolo Bonzini
2016-07-13 14:40 ` Radim Krčmář
2016-07-12 20:09 ` [PATCH v3 12/14] KVM: x86: add a flag to disable KVM x2apic broadcast quirk Radim Krčmář
2016-07-13 8:38 ` Paolo Bonzini
2016-07-13 15:14 ` Radim Krčmář
2016-07-13 15:30 ` Paolo Bonzini
2016-07-13 10:15 ` Paolo Bonzini
2016-07-13 14:52 ` Radim Krčmář
2016-07-12 20:09 ` [PATCH v3 13/14] KVM: x86: bump MAX_VCPUS to 288 Radim Krčmář
2016-07-12 20:09 ` [PATCH v3 14/14] KVM: x86: bump KVM_MAX_VCPU_ID to 1023 Radim Krčmář
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