On 18.11.21 00:44, Sean Christopherson wrote:
> On Tue, Nov 16, 2021, Juergen Gross wrote:
>> diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c
>> index 816a82515dcd..64ba9b1c8b3d 100644
>> --- a/arch/x86/kvm/ioapic.c
>> +++ b/arch/x86/kvm/ioapic.c
>> @@ -685,11 +685,21 @@ static const struct kvm_io_device_ops ioapic_mmio_ops = {
>>   int kvm_ioapic_init(struct kvm *kvm)
>>   {
>>   	struct kvm_ioapic *ioapic;
>> +	size_t sz;
>>   	int ret;
>>   
>> -	ioapic = kzalloc(sizeof(struct kvm_ioapic), GFP_KERNEL_ACCOUNT);
>> +	sz = sizeof(struct kvm_ioapic) +
>> +	     sizeof(*ioapic->rtc_status.dest_map.map) *
>> +		    BITS_TO_LONGS(KVM_MAX_VCPU_IDS) +
>> +	     sizeof(*ioapic->rtc_status.dest_map.vectors) *
>> +		    (KVM_MAX_VCPU_IDS);
>> +	ioapic = kzalloc(sz, GFP_KERNEL_ACCOUNT);
>>   	if (!ioapic)
>>   		return -ENOMEM;
>> +	ioapic->rtc_status.dest_map.map = (void *)(ioapic + 1);
> 
> Oof.  Just do separate allocations.  I highly doubt the performance of the
> emulated RTC hinges on the spatial locality of the bitmap and array.  The array
> is going to end up in a second page for most configuration anyways.

Okay, fine with me.


Juergen