On Thu, Dec 20, 2018 at 06:56:08PM +0100, Radim Kr??m???? wrote:
>2018-11-05 14:45+0800, Wei Yang:
>> Commit af585b921e5d ("KVM: Halt vcpu if page it tries to access is
>> swapped out") introduces async_pf.
>>
>> The gfn hash table size is defined as:
>>
>> gfn_t gfns[roundup_pow_of_two(ASYNC_PF_PER_VCPU)];
>>
>> And iterations in arch/x86/kvm/x86.c are checked with:
>>
>> i < roundup_pow_of_two(ASYNC_PF_PER_VCPU)
>>
>> While the check in kvm_setup_async_pf() is:
>>
>> if (vcpu->async_pf.queued >= ASYNC_PF_PER_VCPU)
>>
>> Generally this works good, while the check is not exact.
>>
>> This patch adjust the check in kvm_setup_async_pf() to use the same
>> boundary as others.
>>
>> Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
>> ---
>> virt/kvm/async_pf.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
>> index 23c2519c5b32..4f4f6eac88a4 100644
>> --- a/virt/kvm/async_pf.c
>> +++ b/virt/kvm/async_pf.c
>> @@ -182,7 +182,7 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, unsigned long hva,
>> {
>> struct kvm_async_pf *work;
>>
>> - if (vcpu->async_pf.queued >= ASYNC_PF_PER_VCPU)
>> + if (vcpu->async_pf.queued >= roundup_pow_of_two(ASYNC_PF_PER_VCPU))
>
>This is actually correct.
>
>Unlike the others in arch/x86, this condition is in general code that
>should have no idea about architectural constraints, like
>ASYNC_PF_PER_VCPU being a power of two.
>
>It'd be better to change the x86 code to avoid the weird
>roundup_pow_of_two() everywhere. I'm thinking about
>
> #define ASYNC_PF_PER_VCPU_ORDER 6
> #define ASYNC_PF_PER_VCPU (1 << ASYNC_PF_PER_VCPU)
>
Thats reasonable, thanks.
>Thanks.
--
Wei Yang
Help you, Help me
