[PATCH v3 14/14] KVM: x86: bump KVM_MAX_VCPU_ID to 1023

[Radim Krčmář]

kzalloc was replaced with kvm_kvzalloc to allow non-contiguous areas and
rcu had to be modified to cope with it.

The practical limit for KVM_MAX_VCPU_ID right now is INT_MAX, but lower
value was chosen in case there were bugs.  1023 is sufficient maximum
APIC ID for 288 VCPUs.

Signed-off-by: Radim Krčmář <rkrc...@redhat.com>
---
 arch/x86/include/asm/kvm_host.h |  1 +
 arch/x86/kvm/lapic.c            | 13 ++++++++++---
 arch/x86/kvm/x86.c              |  2 +-
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 276d6f449d13..30241a2af2a6 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -36,6 +36,7 @@
 
 #define KVM_MAX_VCPUS 288
 #define KVM_SOFT_MAX_VCPUS 240
+#define KVM_MAX_VCPU_ID 1023
 #define KVM_USER_MEM_SLOTS 509
 /* memory slots that are not exposed to userspace */
 #define KVM_PRIVATE_MEM_SLOTS 3
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 46f1d1c93420..41d782212cea 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -147,6 +147,13 @@ static inline bool kvm_apic_map_get_logical_dest(struct 
kvm_apic_map *map,
        }
 }
 
+static void kvm_apic_map_free(struct rcu_head *rcu)
+{
+       struct kvm_apic_map *map = container_of(rcu, struct kvm_apic_map, rcu);
+
+       kvfree(map);
+}
+
 static void recalculate_apic_map(struct kvm *kvm)
 {
        struct kvm_apic_map *new, *old = NULL;
@@ -160,8 +167,8 @@ static void recalculate_apic_map(struct kvm *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);
+       new = kvm_kvzalloc(sizeof(struct kvm_apic_map) +
+                          sizeof(struct kvm_lapic *) * ((u64)max_id + 1));
 
        if (!new)
                goto out;
@@ -206,7 +213,7 @@ out:
        mutex_unlock(&kvm->arch.apic_map_lock);
 
        if (old)
-               kfree_rcu(old, rcu);
+               call_rcu(&old->rcu, kvm_apic_map_free);
 
        kvm_make_scan_ioapic_request(kvm);
 }
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4bab85f82a96..c41a51fe7221 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7927,7 +7927,7 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
        kfree(kvm->arch.vpic);
        kfree(kvm->arch.vioapic);
        kvm_free_vcpus(kvm);
-       kfree(rcu_dereference_check(kvm->arch.apic_map, 1));
+       kvfree(rcu_dereference_check(kvm->arch.apic_map, 1));
        kvm_mmu_uninit_vm(kvm);
 }
 
-- 
2.9.0