Re: [dpdk-dev] [PATCH v3 3/3] vhost: prevent zero copy mode if iommu is on

[Adrian Moreno <amorenoz@redhat.com>]

On 10/8/19 8:23 AM, Tiwei Bie wrote:
> On Fri, Sep 27, 2019 at 08:37:59PM +0200, Adrian Moreno wrote:
>> The simltaneous use of dequeue_zero_copy and IOMMU is problematic.
>> Not only because IOVA_VA mode is not supported but also because the
>> potential invalidation of guest pages while the buffers are in use,
>> is not handled.
>>
>> Prevent these two features to be enabled simultaneosly.
>>
>> Fixes: 69c90e98f483 ("vhost: enable IOMMU support")
>> Cc: maxime.coquelin@redhat.com
>> Cc: stable@dpdk.org
>>
>> Signed-off-by: Adrian Moreno <amorenoz@redhat.com>
>> ---
>>  lib/librte_vhost/socket.c | 8 ++++++++
>>  1 file changed, 8 insertions(+)
> 
> Reviewed-by: Tiwei Bie <tiwei.bie@intel.com>
> 
>>
>> diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c
>> index 274988c4d..534a7ffe3 100644
>> --- a/lib/librte_vhost/socket.c
>> +++ b/lib/librte_vhost/socket.c
>> @@ -871,6 +871,14 @@ rte_vhost_driver_register(const char *path, uint64_t flags)
>>  	}
>>  	vsocket->dequeue_zero_copy = flags & RTE_VHOST_USER_DEQUEUE_ZERO_COPY;
>>  
>> +	if (vsocket->dequeue_zero_copy &&
>> +	   (flags & RTE_VHOST_USER_IOMMU_SUPPORT)) {
> 
> It's better to add one more space before '(flags ...'
OK. I'll add it in the next version.
> 
>> +		RTE_LOG(ERR, VHOST_CONFIG,
>> +			"error: enabling dequeue zero copy and IOMMU features "
>> +			"simultaneously is not supported\n");
>> +		goto out_mutex;
>> +	}
>> +
>>  	/*
>>  	 * Set the supported features correctly for the builtin vhost-user
>>  	 * net driver.
>> -- 
>> 2.21.0
>>

Thanks.
-Adrián