2017-04-19 10:08+0200, Christian Borntraeger:
> On 04/13/2017 10:19 PM, Radim Krčmář wrote:
>> The only user of KVM_MAX_VCPU is switched to kvm->max_vcpu.
>>
>> The limit could have been INT_MAX as it makes no difference, but there
>> is no point in making it bigger than KVM_MAX_VCPU_ID.
>>
>> Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
>> ---
>> arch/x86/include/asm/kvm_host.h | 1 +
>> arch/x86/kvm/irq_comm.c | 4 ++--
>> 2 files changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
>> index 2cc5ec7cc6f5..eeeb88eedabf 100644
>> --- a/arch/x86/include/asm/kvm_host.h
>> +++ b/arch/x86/include/asm/kvm_host.h
>> @@ -38,6 +38,7 @@
>> #define KVM_MAX_VCPUS 288
>> #define KVM_SOFT_MAX_VCPUS 240
>> #define KVM_MAX_VCPU_ID 1023
>> +#define KVM_CONFIGURABLE_MAX_VCPUS KVM_MAX_VCPU_ID
>> #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/irq_comm.c b/arch/x86/kvm/irq_comm.c
>> index 4517a4c2ac3a..a7baeb44539a 100644
>> --- a/arch/x86/kvm/irq_comm.c
>> +++ b/arch/x86/kvm/irq_comm.c
>> @@ -60,7 +60,7 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
>> {
>> int i, r = -1;
>> struct kvm_vcpu *vcpu, *lowest = NULL;
>> - unsigned long dest_vcpu_bitmap[BITS_TO_LONGS(KVM_MAX_VCPUS)];
>> + unsigned long dest_vcpu_bitmap[BITS_TO_LONGS(kvm->max_vcpus)];
>
> Doesnt that allow unlimited stack usage?
Right, it doesn't scale.
kvm->max_vcpus is at most KVM_CONFIGURABLE_MAX_VCPUS, but that will be
bigger than the stack. I'll allocate the bitmap in v2.
Thanks.
