Re: [PATCH v3] usertools: add check for IOMMU support in dpdk-devbind

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

On 21-Mar-22 12:27 PM, Fidaullah Noonari wrote:
> binding with vfio driver, when IOMMU is disabled, causes program to crash.
> this patch adds a flag for noiommmu-mode. when this is set, if IOMMU is
> disabled, it changes vfio into unsafe noiommu mode and prints warning
> message.
> 
> Signed-off-by: Fidaullah Noonari <fidaullah.noonari@emumba.com>
> ---

Hi,

> +def check_noiommu_mode():
> +    """checks and enables the noiommu mode for vfio drivers"""
> +    global noiommu_flag
> +    filename = "/sys/module/vfio/parameters/enable_unsafe_noiommu_mode"
> +
> +    try:
> +        with open(filename,"r") as f:
> +            if f.read(1) == "1":
> +                return
> +    except OSError as err:
> +        sys.exit("Error: failed to enable unsafe noiommu mode - Cannot open %s: %s"
> +                % (filename, err))

Nitpick, but maybe use f-strings instead of old-school string interpolation?

> +
> +    if not noiommu_flag:
> +        print("Error: failed to bind vfio-pci - IOMMU support is disabled")
> +        print("Info: use --noiommu-mode for binding in noiommu mode")
> +        sys.exit()
> +
> +    try:
> +        with open(filename, "w") as f:
> +            f.write("1")
> +            f.close()
> +    except OSError as err:
> +        sys.exit("Error: failed to enable unsafe noiommu mode - Cannot open %s: %s"
> +                % (filename, err))

Same as above.

Otherwise LGTM,

Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>

-- 
Thanks,
Anatoly