Re: [dpdk-dev] [PATCH v5 08/11] eal: pci: introduce RTE_KDRV_VFIO_NOIOMMUi driver mode

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

Hi Santosh,

> +int
> +pci_vfio_is_noiommu(struct rte_pci_device *pci_dev) {
> +	FILE *fp;
> +	struct rte_pci_addr *loc;
> +	const char *path =
> "/sys/module/vfio/parameters/enable_unsafe_noiommu_mode";
> +	char filename[PATH_MAX] = {0};
> +	char buf[PATH_MAX] = {0};
> +
> +	/*
> +	 * 1. chk vfio-noiommu mode set in kernel driver
> +	 * 2. verify pci device attached to vfio-noiommu driver
> +	 * example:
> +	 * cd /sys/bus/pci/drivers/vfio-pci/<virtio_dev_addr>/iommu_group
> +	 * > cat name
> +	 * > vfio-noiommu --> means virtio_dev attached to vfio-noiommu
> driver
> +	 */
> +
> +	fp = fopen(path, "r");
> +	if (fp == NULL) {
> +		RTE_LOG(ERR, EAL, "can't open %s\n", path);
> +		return -1;
> +	}
> +
> +	if (fread(buf, sizeof(char), 1, fp) != 1) {
> +		RTE_LOG(ERR, EAL, "can't read from file %s\n", path);
> +		fclose(fp);
> +		return -1;
> +	}
> +
> +	if (strncmp(buf, "Y", 1) != 0) {
> +		RTE_LOG(ERR, EAL, "[%s]: vfio: noiommu mode not set\n",
> path);
> +		fclose(fp);
> +		return -1;
> +	}
> +
> +	fclose(fp);
> +
> +	/* 2. chk whether attached driver is vfio-noiommu or not */
> +	loc = &pci_dev->addr;
> +	snprintf(filename, sizeof(filename),
> +		     SYSFS_PCI_DEVICES "/" PCI_PRI_FMT
> "/iommu_group/name",
> +		     loc->domain, loc->bus, loc->devid, loc->function);
> +
> +	/* check for vfio-noiommu */
> +	fp = fopen(filename, "r");
> +	if (fp == NULL) {
> +		RTE_LOG(ERR, EAL, "can't open %s\n", filename);
> +		return -1;
> +	}
> +
> +	if (fread(buf, sizeof(char), sizeof("vfio-noiommu"), fp) !=
> +		  sizeof("vfio-noiommu")) {
> +		RTE_LOG(ERR, EAL, "can't read from file %s\n", filename);
> +		fclose(fp);
> +		return -1;
> +	}
> +
> +	if (strncmp(buf, "vfio-noiommu", strlen("vfio-noiommu")) != 0) {
> +		RTE_LOG(ERR, EAL, "not a vfio-noiommu driver\n");
> +		fclose(fp);
> +		return -1;
> +	}
> +
> +	fclose(fp);
> +
> +	return 0;
> +}

Since this is a public non-performance critical API, shouldn't we check if pci_dev is NULL? Otherwise the patch-set seems fine to me as far as VFIO parts are concerned.

Thanks,
Anatoly