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From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: Gaëtan Rivet <grive@u256.net>
Cc: dev@dpdk.org, matan@mellanox.com, xiao.w.wang@intel.com,
	zhihong.wang@intel.com, xiaolong.ye@intel.com,
	chenbo.xia@intel.com, david.marchand@redhat.com,
	amorenoz@redhat.com, shreyansh.jain@nxp.com,
	viacheslavo@mellanox.com, hemant.agrawal@nxp.com,
	sachin.saxena@nxp.com
Subject: Re: [dpdk-dev] [PATCH 03/14] vhost: introduce vDPA devices class
Date: Mon, 15 Jun 2020 11:15:41 +0200
Message-ID: <c3818c39-7c0e-44b0-f66f-3b93f41b9df3@redhat.com> (raw)
In-Reply-To: <20200612123715.hfboy57s4t66xnor@u256.net>



On 6/12/20 2:37 PM, Gaëtan Rivet wrote:
> On 11/06/20 23:37 +0200, Maxime Coquelin wrote:
>> This patch introduces vDPA device class. It will enable
>> application to iterate over the vDPA devices.
>>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>> ---
>>  lib/librte_vhost/vdpa.c | 116 +++++++++++++++++++++++++++++++++-------
>>  1 file changed, 98 insertions(+), 18 deletions(-)
>>
>> diff --git a/lib/librte_vhost/vdpa.c b/lib/librte_vhost/vdpa.c
>> index b2b2a105f1..61ab9aadb4 100644
>> --- a/lib/librte_vhost/vdpa.c
>> +++ b/lib/librte_vhost/vdpa.c
>> @@ -10,11 +10,12 @@
>>  
>>  #include <stdbool.h>
>>  
>> +#include <rte_class.h>
>>  #include <rte_malloc.h>
>>  #include "rte_vdpa.h"
>>  #include "vhost.h"
>>  
>> -static struct rte_vdpa_device *vdpa_devices[MAX_VHOST_DEVICE];
>> +static struct rte_vdpa_device vdpa_devices[MAX_VHOST_DEVICE];
>>  static uint32_t vdpa_device_num;
>>  
>>  static bool
>> @@ -46,35 +47,28 @@ rte_vdpa_register_device(struct rte_vdpa_dev_addr *addr,
>>  		struct rte_vdpa_dev_ops *ops)
>>  {
>>  	struct rte_vdpa_device *dev;
>> -	char device_name[MAX_VDPA_NAME_LEN];
>>  	int i;
>>  
>>  	if (vdpa_device_num >= MAX_VHOST_DEVICE || addr == NULL || ops == NULL)
>>  		return -1;
>>  
>>  	for (i = 0; i < MAX_VHOST_DEVICE; i++) {
>> -		dev = vdpa_devices[i];
>> -		if (dev && is_same_vdpa_device(&dev->addr, addr))
>> +		dev = &vdpa_devices[i];
>> +		if (dev->ops && is_same_vdpa_device(&dev->addr, addr))
>>  			return -1;
>>  	}
>>  
>>  	for (i = 0; i < MAX_VHOST_DEVICE; i++) {
>> -		if (vdpa_devices[i] == NULL)
>> +		if (vdpa_devices[i].ops == NULL)
>>  			break;
>>  	}
>>  
>>  	if (i == MAX_VHOST_DEVICE)
>>  		return -1;
>>  
>> -	snprintf(device_name, sizeof(device_name), "vdpa-dev-%d", i);
>> -	dev = rte_zmalloc(device_name, sizeof(struct rte_vdpa_device),
>> -			RTE_CACHE_LINE_SIZE);
>> -	if (!dev)
>> -		return -1;
>> -
>> +	dev = &vdpa_devices[i];
>>  	memcpy(&dev->addr, addr, sizeof(struct rte_vdpa_dev_addr));
>>  	dev->ops = ops;
>> -	vdpa_devices[i] = dev;
>>  	vdpa_device_num++;
>>  
>>  	return i;
>> @@ -83,11 +77,10 @@ rte_vdpa_register_device(struct rte_vdpa_dev_addr *addr,
>>  int
>>  rte_vdpa_unregister_device(int did)
>>  {
>> -	if (did < 0 || did >= MAX_VHOST_DEVICE || vdpa_devices[did] == NULL)
>> +	if (did < 0 || did >= MAX_VHOST_DEVICE || vdpa_devices[did].ops == NULL)
>>  		return -1;
>>  
>> -	rte_free(vdpa_devices[did]);
>> -	vdpa_devices[did] = NULL;
>> +	memset(&vdpa_devices[did], 0, sizeof(struct rte_vdpa_device));
>>  	vdpa_device_num--;
>>  
>>  	return did;
>> @@ -103,8 +96,11 @@ rte_vdpa_find_device_id(struct rte_vdpa_dev_addr *addr)
>>  		return -1;
>>  
>>  	for (i = 0; i < MAX_VHOST_DEVICE; ++i) {
>> -		dev = vdpa_devices[i];
>> -		if (dev && is_same_vdpa_device(&dev->addr, addr))
>> +		dev = &vdpa_devices[i];
>> +		if (dev->ops == NULL)
>> +			continue;
>> +
>> +		if (is_same_vdpa_device(&dev->addr, addr))
>>  			return i;
>>  	}
>>  
>> @@ -117,7 +113,7 @@ rte_vdpa_get_device(int did)
>>  	if (did < 0 || did >= MAX_VHOST_DEVICE)
>>  		return NULL;
>>  
>> -	return vdpa_devices[did];
>> +	return &vdpa_devices[did];
>>  }
>>  
>>  int
>> @@ -227,3 +223,87 @@ rte_vdpa_relay_vring_used(int vid, uint16_t qid, void *vring_m)
>>  		free_ind_table(idesc);
>>  	return -1;
>>  }
>> +
>> +static uint16_t
>> +vdpa_dev_to_id(const struct rte_vdpa_device *dev)
>> +{
>> +	if (dev == NULL)
>> +		return MAX_VHOST_DEVICE;
> 
> I know it comes from ethdev, this helper was introduced by 214ed1acd12
> and changed the comparison type from ptrdiff_t to uin16_t.
> 
> This is incorrect, ideally it should instead be a ptrdiff_t, then
> if within acceptable range it should be casted to uin16_t to be used as
> an index.
> 
>> +	return dev - vdpa_devices;
>> +}
>> +
>> +static int
>> +vdpa_dev_match(struct rte_vdpa_device *dev,
>> +	      const struct rte_device *rte_dev)
>> +{
>> +	struct rte_vdpa_dev_addr addr;
>> +
>> +	/*  Only PCI bus supported for now */
>> +	if (strcmp(rte_dev->bus->name, "pci") != 0)
>> +		return -1;
>> +
>> +	addr.type = VDPA_ADDR_PCI;
>> +
>> +	if (rte_pci_addr_parse(rte_dev->name, &addr.pci_addr) != 0)
>> +		return -1;
>> +
>> +	if (!is_same_vdpa_device(&dev->addr, &addr))
>> +		return -1;
>> +
>> +	return 0;
>> +}
>> +
>> +/* Generic rte_vdpa_dev comparison function. */
>> +typedef int (*rte_vdpa_cmp_t)(struct rte_vdpa_device *,
>> +		const struct rte_device *rte_dev);
>> +
>> +static struct rte_vdpa_device *
>> +vdpa_find_device(const struct rte_vdpa_device *start, rte_vdpa_cmp_t cmp,
>> +		struct rte_device *rte_dev)
>> +{
>> +	struct rte_vdpa_device *dev;
>> +	ptrdiff_t idx;
> 
> The ptrdiff_t was used in ethdev due to the original
> 
>    start - &rte_eth_devices[0] + 1;
> 
> The diff was removed by commit 214ed1acd12 . 'idx' should be
> the proper type to hold a device id, here probably uint16_t.

Ok, makes sense.

> Ethdev class should be cleaned up as well.
> 
>> +
>> +	/* Avoid Undefined Behaviour */
>> +	if (start != NULL &&
>> +	    (start < &vdpa_devices[0] ||
>> +	     start >= &vdpa_devices[MAX_VHOST_DEVICE]))
>> +		return NULL;
> 
> Same as before, this guard made sense mostly for the diff following.
> It is coupled to the "random ptr to static array" comparison happening,
> it would be better in vpda_dev_to_id() I think.

OK, I will clean that in next version, but but this part moves away
later in the series, when switching to linked-list.

Thanks,
Maxime

>> +
>> +	if (start != NULL)
>> +		idx = vdpa_dev_to_id(start) + 1;
>> +	else
>> +		idx = 0;
>> +	for (; idx < MAX_VHOST_DEVICE; idx++) {
>> +		dev = &vdpa_devices[idx];
>> +		/*
>> +		 * ToDo: Certainly better to introduce a state field,
>> +		 * but rely on ops being set for now.
>> +		 */
>> +		if (dev->ops == NULL)
>> +			continue;
>> +		if (cmp(dev, rte_dev) == 0)
>> +			return dev;
>> +	}
>> +	return NULL;
>> +}
>> +
>> +static void *
>> +vdpa_dev_iterate(const void *start,
>> +		const char *str,
>> +		const struct rte_dev_iterator *it)
>> +{
>> +	struct rte_vdpa_device *vdpa_dev = NULL;
>> +
>> +	RTE_SET_USED(str);
>> +
>> +	vdpa_dev = vdpa_find_device(start, vdpa_dev_match, it->device);
>> +
>> +	return vdpa_dev;
>> +}
>> +
>> +static struct rte_class rte_class_vdpa = {
>> +	.dev_iterate = vdpa_dev_iterate,
>> +};
>> +
>> +RTE_REGISTER_CLASS(vdpa, rte_class_vdpa);
>> -- 
>> 2.26.2
>>
> 


  reply	other threads:[~2020-06-15  9:15 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-11 21:37 [dpdk-dev] [PATCH 00/14] vDPA API and framework rework Maxime Coquelin
2020-06-11 21:37 ` [dpdk-dev] [PATCH 01/14] bus/dpaa: fix null pointer dereference Maxime Coquelin
2020-06-12  9:48   ` Gaëtan Rivet
2020-06-11 21:37 ` [dpdk-dev] [PATCH 02/14] bus/fslmc: " Maxime Coquelin
2020-06-11 21:37 ` [dpdk-dev] [PATCH 03/14] vhost: introduce vDPA devices class Maxime Coquelin
2020-06-12 12:37   ` Gaëtan Rivet
2020-06-15  9:15     ` Maxime Coquelin [this message]
2020-06-11 21:37 ` [dpdk-dev] [PATCH 04/14] vhost: make vDPA framework bus agnostic Maxime Coquelin
2020-06-12 12:46   ` Gaëtan Rivet
2020-06-15  9:17     ` Maxime Coquelin
2020-06-19 11:14   ` Adrian Moreno
2020-06-19 15:11     ` Maxime Coquelin
2020-06-22  9:49       ` Adrian Moreno
2020-06-22 12:34         ` Maxime Coquelin
2020-06-11 21:37 ` [dpdk-dev] [PATCH 05/14] vhost: replace device ID in vDPA ops Maxime Coquelin
2020-06-11 21:37 ` [dpdk-dev] [PATCH 06/14] vhost: replace vDPA device ID in Vhost Maxime Coquelin
2020-06-11 21:37 ` [dpdk-dev] [PATCH 07/14] vhost: replace device ID in applications Maxime Coquelin
2020-06-11 21:37 ` [dpdk-dev] [PATCH 08/14] vhost: remove useless vDPA API Maxime Coquelin
2020-06-11 21:37 ` [dpdk-dev] [PATCH 09/14] vhost: use linked-list for vDPA devices Maxime Coquelin
2020-06-11 21:37 ` [dpdk-dev] [PATCH 10/14] vhost: introduce wrappers for some vDPA ops Maxime Coquelin
2020-06-11 21:37 ` [dpdk-dev] [PATCH 11/14] examples/vdpa: use new wrappers instead of ops Maxime Coquelin
2020-06-11 21:37 ` [dpdk-dev] [PATCH 12/14] examples/vdpa: remove useless device count Maxime Coquelin
2020-06-11 21:37 ` [dpdk-dev] [PATCH 13/14] vhost: remove vDPA device count API Maxime Coquelin
2020-06-11 21:37 ` [dpdk-dev] [PATCH 14/14] vhost: split vDPA header file Maxime Coquelin
2020-06-12  9:38 ` [dpdk-dev] [PATCH 00/14] vDPA API and framework rework Gaëtan Rivet

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