On Wed, Aug 04, 2021 at 09:37:45AM +0200, Greg KH wrote: > On Tue, Aug 03, 2021 at 12:02:24PM -0700, Russ Weight wrote: > > > > > > On 8/2/21 10:49 PM, Greg KH wrote: > > >> If the request_firmware() implementation is not acceptable, then would > > >> you agree that an IOCTL implementation is our best option? > > > There is no difference in the end between using an ioctl, or a sysfs > > > file, to provide the filename of your firmware, don't get hung up on > > > that. > > > > I meant to suggest that passing file data (not a filename) through an > > IOCTL might be better for this use case than trying to use request_firmware. > > We have to, somehow, allow the user to point us to the desired image > > data (which could be a root-entry-hash, or an FPGA image). We can't > > really use a fixed filename modified by device version as many of > > the devices do. > > Ah, yes, a "normal" write command might be best for this as that can be > properly containerized and controlled. > > > > By providing a "filename", you are going around all of the namespace and > > > other "container" protection that the kernel provides, and allowing > > > processes to potentially load files that are normally outside of their > > > scope to the hardware. If you are willing to allow that security > > > "escape", wonderful, but you better document the heck out of it and > > > explain why this is allowed for your special hardware and use case. > > > > > > As you are expecting this to work "in the cloud", I do not think that > > > the operators of such hardware are really going to be all that happy to > > > see this type of interface given these reasons. > > > > > > What is wrong with the current fpga firmware api that somehow is lacking > > > for your special hardware, that other devices do not have to worry > > > about? > > The existing framework wants to update the live image in the FPGA, > > whereas for this device, we are passing signed data to BMC firmware > > which will store it in FLASH to be loaded on a subsequent boot of > > the card. > > > > The existing framework needs to manage FPGA state, whereas for this > > device, it is just a transfer of signed data. We also have to handle > > a total transfer/authentication time of up to 45 minutes, so we are > > using a kernel worker thread for the update. > > > > Perhaps the name, fpga security manager, is wrong? Maybe something > > like fpga_sec_image_xfer is better? > > It does not sound like this has anything to do with "security", and > rather is just a normal firmware upload, so "fpga_image_upload()" > perhaps? I had originally suggested 'load' and 'persist' or 'load' and 'update or something of that sort. Taking one step back, maybe the case could be made for a generic 'persistent firmware' update framework that addresses use-cases that require updating firmware that may take extended periods of time. A similar case that comes to mind would be writing firmware to an external flash on a Renesas xHCI controller, or updating the BMC firmware for a plug-in card with BMC. - Moritz
