Re: [dpdk-dev] [PATCH v3 11/19] vhost: introduce postcopy's advise message

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 10/05/2018 01:58 PM, Ilya Maximets wrote:
> Cleanup part is missing in this patch.
> We should close and clear postcopy_ufd in vhost_backend_cleanup().

Good catch, I'll spin a v4 with your suggestion.

Thanks,
Maxime

> Best regards, Ilya Maximets.
> 
> On 04.10.2018 11:13, Maxime Coquelin wrote:
>> This patch opens a userfaultfd and sends it back to Qemu's
>> VHOST_USER_POSTCOPY_ADVISE request.
>>
>> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>> ---
>>   lib/librte_vhost/vhost.h      |  2 ++
>>   lib/librte_vhost/vhost_user.c | 44 +++++++++++++++++++++++++++++++++++
>>   lib/librte_vhost/vhost_user.h |  3 ++-
>>   3 files changed, 48 insertions(+), 1 deletion(-)
>>
>> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
>> index 25ffd7614..21722d8a8 100644
>> --- a/lib/librte_vhost/vhost.h
>> +++ b/lib/librte_vhost/vhost.h
>> @@ -363,6 +363,8 @@ struct virtio_net {
>>   	int			slave_req_fd;
>>   	rte_spinlock_t		slave_req_lock;
>>   
>> +	int			postcopy_ufd;
>> +
>>   	/*
>>   	 * Device id to identify a specific backend device.
>>   	 * It's set to -1 for the default software implementation.
>> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
>> index 0a1934649..3d4fc60fc 100644
>> --- a/lib/librte_vhost/vhost_user.c
>> +++ b/lib/librte_vhost/vhost_user.c
>> @@ -24,13 +24,19 @@
>>   #include <stdlib.h>
>>   #include <string.h>
>>   #include <unistd.h>
>> +#include <fcntl.h>
>> +#include <sys/ioctl.h>
>>   #include <sys/mman.h>
>>   #include <sys/types.h>
>>   #include <sys/stat.h>
>> +#include <sys/syscall.h>
>>   #include <assert.h>
>>   #ifdef RTE_LIBRTE_VHOST_NUMA
>>   #include <numaif.h>
>>   #endif
>> +#ifdef RTE_LIBRTE_VHOST_POSTCOPY
>> +#include <linux/userfaultfd.h>
>> +#endif
>>   
>>   #include <rte_common.h>
>>   #include <rte_malloc.h>
>> @@ -69,6 +75,7 @@ static const char *vhost_message_str[VHOST_USER_MAX] = {
>>   	[VHOST_USER_IOTLB_MSG]  = "VHOST_USER_IOTLB_MSG",
>>   	[VHOST_USER_CRYPTO_CREATE_SESS] = "VHOST_USER_CRYPTO_CREATE_SESS",
>>   	[VHOST_USER_CRYPTO_CLOSE_SESS] = "VHOST_USER_CRYPTO_CLOSE_SESS",
>> +	[VHOST_USER_POSTCOPY_ADVISE]  = "VHOST_USER_POSTCOPY_ADVISE",
>>   };
>>   
>>   /* The possible results of a message handling function */
>> @@ -1509,6 +1516,42 @@ vhost_user_iotlb_msg(struct virtio_net **pdev, struct VhostUserMsg *msg,
>>   	return VH_RESULT_OK;
>>   }
>>   
>> +static int
>> +vhost_user_set_postcopy_advise(struct virtio_net **pdev,
>> +			struct VhostUserMsg *msg,
>> +			int main_fd __rte_unused)
>> +{
>> +	struct virtio_net *dev = *pdev;
>> +#ifdef RTE_LIBRTE_VHOST_POSTCOPY
>> +	struct uffdio_api api_struct;
>> +
>> +	dev->postcopy_ufd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
>> +
>> +	if (dev->postcopy_ufd == -1) {
>> +		RTE_LOG(ERR, VHOST_CONFIG, "Userfaultfd not available: %s\n",
>> +				strerror(errno));
>> +		return VH_RESULT_ERR;
>> +	}
>> +	api_struct.api = UFFD_API;
>> +	api_struct.features = 0;
>> +	if (ioctl(dev->postcopy_ufd, UFFDIO_API, &api_struct)) {
>> +		RTE_LOG(ERR, VHOST_CONFIG, "UFFDIO_API ioctl failure: %s\n",
>> +				strerror(errno));
>> +		close(dev->postcopy_ufd);
>> +		return VH_RESULT_ERR;
>> +	}
>> +	msg->fds[0] = dev->postcopy_ufd;
>> +	msg->fd_num = 1;
>> +
>> +	return VH_RESULT_REPLY;
>> +#else
>> +	dev->postcopy_ufd = -1;
>> +	msg->fd_num = 0;
>> +
>> +	return VH_RESULT_ERR;
>> +#endif
>> +}
>> +
>>   typedef int (*vhost_message_handler_t)(struct virtio_net **pdev,
>>   					struct VhostUserMsg *msg,
>>   					int main_fd);
>> @@ -1536,6 +1579,7 @@ static vhost_message_handler_t vhost_message_handlers[VHOST_USER_MAX] = {
>>   	[VHOST_USER_NET_SET_MTU] = vhost_user_net_set_mtu,
>>   	[VHOST_USER_SET_SLAVE_REQ_FD] = vhost_user_set_req_fd,
>>   	[VHOST_USER_IOTLB_MSG] = vhost_user_iotlb_msg,
>> +	[VHOST_USER_POSTCOPY_ADVISE] = vhost_user_set_postcopy_advise,
>>   };
>>   
>>   
>> diff --git a/lib/librte_vhost/vhost_user.h b/lib/librte_vhost/vhost_user.h
>> index dd0262f8f..2030b40a5 100644
>> --- a/lib/librte_vhost/vhost_user.h
>> +++ b/lib/librte_vhost/vhost_user.h
>> @@ -50,7 +50,8 @@ typedef enum VhostUserRequest {
>>   	VHOST_USER_IOTLB_MSG = 22,
>>   	VHOST_USER_CRYPTO_CREATE_SESS = 26,
>>   	VHOST_USER_CRYPTO_CLOSE_SESS = 27,
>> -	VHOST_USER_MAX = 28
>> +	VHOST_USER_POSTCOPY_ADVISE = 28,
>> +	VHOST_USER_MAX = 29
>>   } VhostUserRequest;
>>   
>>   typedef enum VhostUserSlaveRequest {
>>