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KVM: x86: bump KVM_MAX_VCPU_ID to 1023
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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 <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
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rkrcmar authored and bonzini committed Jul 14, 2016
1 parent 682f732 commit af1bae5
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Showing 3 changed files with 12 additions and 4 deletions.
1 change: 1 addition & 0 deletions arch/x86/include/asm/kvm_host.h
Original file line number Diff line number Diff line change
Expand Up @@ -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
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13 changes: 10 additions & 3 deletions arch/x86/kvm/lapic.c
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand All @@ -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;
Expand Down Expand Up @@ -206,7 +213,7 @@ static void recalculate_apic_map(struct kvm *kvm)
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);
}
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2 changes: 1 addition & 1 deletion arch/x86/kvm/x86.c
Original file line number Diff line number Diff line change
Expand Up @@ -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);
}

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