[dpdk-dev] [PATCH v2] VFIO: Avoid to enable vfio while the module not loaded
Qiu, Michael
michael.qiu at intel.com
Mon Dec 8 08:25:53 CET 2014
On 12/5/2014 6:00 PM, Burakov, Anatoly wrote:
> Hi Michael,
>
> Few nitpicks :-) (wording of the log message I guess is up to Thomas, I won't comment on that)
>
>> lib/librte_eal/common/eal_private.h | 36
>> ++++++++++++++++++++++++++++++
>> lib/librte_eal/linuxapp/eal/eal_pci_vfio.c | 24 +++++++++++++++++---
>> 2 files changed, 57 insertions(+), 3 deletions(-)
>>
>> diff --git a/lib/librte_eal/common/eal_private.h
>> b/lib/librte_eal/common/eal_private.h
>> index 232fcec..e741bdb 100644
>> --- a/lib/librte_eal/common/eal_private.h
>> +++ b/lib/librte_eal/common/eal_private.h
>> @@ -35,6 +35,7 @@
>> #define _EAL_PRIVATE_H_
>>
>> #include <stdio.h>
>> +#include <string.h>
>>
>> /**
>> * Initialize the memzone subsystem (private to eal).
>> @@ -203,4 +204,39 @@ int rte_eal_alarm_init(void);
>> */
>> int rte_eal_dev_init(void);
>>
>> +/**
>> + * Function is to check if the kernel module(like, vfio,
>> +vfio_iommu_type1,
>> + * etc.) loaded.
>> + *
>> + * @param module_name
>> + * The module's name which need to be checked
>> + *
>> + * @return
>> + * -1 means error happens(NULL pointer or open failure)
>> + * 0 means the module not loaded
>> + * 1 means the module loaded
>> + */
>> +static inline int
>> +rte_eal_check_module(const char *module_name) {
>> + char mod_name[30]; /* Any module names can be longer than 30
>> bytes? */
>> + int ret = 0;
>> +
>> + if (NULL == module_name)
>> + return -1;
>> + FILE * fd = fopen("/proc/modules", "r");
>> + if (fd == NULL)
>> + return -1;
> Can we add RTE_LOG statement here, with an strerror(errno) like in other places? Fopen failed, we should at least know why :-)
>
>> + while(!feof(fd)) {
>> + fscanf(fd, "%s %*[^\n]", mod_name);
>> + if(!strcmp(mod_name, module_name)) {
> Probably should use strncmp instead of strcmp.
I don't think so, if we check module "vfio", but if given module name
is "vfio_xx", it will also correct if use strncmp.
Thanks,
Michael
>
>> + ret = 1;
>> + break;
>> + }
>> + }
>> + fclose(fd);
>> +
>> + return ret;
>> +}
>> +
>> #endif /* _EAL_PRIVATE_H_ */
>> diff --git a/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
>> b/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
>> index c1246e8..52ab2d0 100644
>> --- a/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
>> +++ b/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
>> @@ -44,6 +44,7 @@
>> #include <rte_tailq.h>
>> #include <rte_eal_memconfig.h>
>> #include <rte_malloc.h>
>> +#include <eal_private.h>
>>
>> #include "eal_filesystem.h"
>> #include "eal_pci_init.h"
>> @@ -339,10 +340,13 @@ pci_vfio_get_container_fd(void)
>> ret = ioctl(vfio_container_fd, VFIO_CHECK_EXTENSION,
>> VFIO_TYPE1_IOMMU);
>> if (ret != 1) {
>> if (ret < 0)
>> - RTE_LOG(ERR, EAL, " could not get IOMMU
>> type, "
>> - "error %i (%s)\n", errno,
>> strerror(errno));
>> + RTE_LOG(ERR, EAL, " could not get IOMMU
>> type,"
>> + " error %i (%s)\n", errno,
>> + strerror(errno));
>> else
>> - RTE_LOG(ERR, EAL, " unsupported IOMMU
>> type!\n");
>> + RTE_LOG(ERR, EAL, " unsupported IOMMU
>> type! "
>> + "expect: VFIO_TYPE1_IOMMU, "
>> + "actual: %d\n", ret);
> I'm not even sure we need this "expected" bit at all. We don't get back the IOMMU type VFIO currently supports; rather, this code checks if VFIO's support for VFIO_TYPE1_IOMMU is enabled or not. So I would change the error message to something more descriptive, such as " required IOMMU type support not present in VFIO!\n", and get rid of the "expected".
>
>> close(vfio_container_fd);
>> return -1;
>> }
>> @@ -788,6 +792,20 @@ pci_vfio_enable(void)
>> vfio_cfg.vfio_groups[i].fd = -1;
>> vfio_cfg.vfio_groups[i].group_no = -1;
>> }
>> +
>> + /* return error directly */
>> + if (rte_eal_check_module("vfio") == -1 ||
>> + rte_eal_check_module("vfio_iommu_type1") == -1)
>> + return -1;
>> +
>> + /* return 0 if not all VFIO modules loaded */
>> + if (rte_eal_check_module("vfio") == 0 ||
>> + rte_eal_check_module("vfio_iommu_type1") == 0) {
>> + RTE_LOG(INFO, EAL, "VFIO modules not all loaded,"
>> + " skip VFIO support ...\n");
>> + return 0;
>> + }
> Can we perhaps make one call per module instead of two? i.e. something like:
>
> int vfio_ret, vfio_ type1_ret;
> vfio_ret = rte_eal_check_module("vfio");
> vfio_type1_ret = rte_eal_check_module("vfio_iommu_type1");
>
> if (vfio_ret == -1 || vfio_type1_ret == -1)
> return -1;
> else if (vfio_ret == 0 || vfio_type1_ret == 0) {
> ....
> return 0;
> }
>
>> +
>> vfio_cfg.vfio_container_fd = pci_vfio_get_container_fd();
>>
>> /* check if we have VFIO driver enabled */
>> --
>> 1.9.3
>
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