Re: [PATCH Kernel v22 3/8] vfio iommu: Cache pgsize_bitmap in struct vfio_iommu

[Kirti Wankhede <kwankhede@nvidia.com>]

On 5/20/2020 3:38 PM, Cornelia Huck wrote:
> On Mon, 18 May 2020 11:26:32 +0530
> Kirti Wankhede <kwankhede@nvidia.com> wrote:
> 
>> Calculate and cache pgsize_bitmap when iommu->domain_list is updated
>> and iommu->external_domain is set for mdev device.
>> Add iommu->lock protection when cached pgsize_bitmap is accessed.
>>
>> Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
>> Reviewed-by: Neo Jia <cjia@nvidia.com>
>> ---
>>   drivers/vfio/vfio_iommu_type1.c | 88 +++++++++++++++++++++++------------------
>>   1 file changed, 49 insertions(+), 39 deletions(-)
>>
> 
> (...)
> 
>> @@ -805,15 +806,14 @@ static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
>>   	iommu->dma_avail++;
>>   }
>>   
>> -static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu)
>> +static void vfio_pgsize_bitmap(struct vfio_iommu *iommu)
> 
> Minor nit: I'd have renamed this function to
> vfio_update_pgsize_bitmap().
> 

Done.

>>   {
>>   	struct vfio_domain *domain;
>> -	unsigned long bitmap = ULONG_MAX;
>>   
>> -	mutex_lock(&iommu->lock);
>> +	iommu->pgsize_bitmap = ULONG_MAX;
>> +
>>   	list_for_each_entry(domain, &iommu->domain_list, next)
>> -		bitmap &= domain->domain->pgsize_bitmap;
>> -	mutex_unlock(&iommu->lock);
>> +		iommu->pgsize_bitmap &= domain->domain->pgsize_bitmap;
>>   
>>   	/*
>>   	 * In case the IOMMU supports page sizes smaller than PAGE_SIZE
> 
> (...)
> 
> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
> 

Thanks.

Kirti