On Sun, Jun 01, 2025 at 12:25:54PM +0200, Borislav Petkov wrote: > Some questions inline... > > On Sat, May 31, 2025 at 03:24:14PM -0700, Luck, Tony wrote: > > EINJ V2 allows the user to perform multiple injections together. > > > > The component_idN/component_syndromeN pairs of files direct the > > "where" and the "what" of each injection. > > > > But the kernel needs to know how many of these pairs to use > > for an injection (to fill in a field in the structure passed > > to the BIOS). > > The kernel could realloc on each write. Or we could allocate the struct to max > elems and trim it before passing it down to BIOS. The actual structure passed to BIOS is the same each time. Just the set_error_type_with_address::einjv2_struct::component_arr_count changed to indicate how many errors to inject. In theory the driver could allocate and copy a correctly sized structure, but Zaid's code here is simpler, an this is hardly a critical path. > > User interface options: > > > > 1) User can zero out the component_idN/component_syndromeN pairs > > that they don't need and have the kernel count how many injections > > are requested by looping to find the zero terminator. > > > > 2) Kernel could zero all pairs after an injection to make the user > > explicitly set the list of targets each time. > > > > 3) User provides the count vis the nr_components file (perhaps > > needs a better name?) > > Yap, agree that the name is not optimal. It can be dropped if we make the user zap previously supplied component_idN/component_syndromeN pairs that are no longer wanted. > > User can inject into each component pairs file and the kernel can put that in > the tracking struct. So you have: > > # echo 4 > component_id0 > # echo A5A5A5A5 > component_syndrome0 > ... set other files and finish with usual > # echo 1 > error_inject > > <--- here, it goes through each component pair and builds the structure to > pass down the BIOS. > > And you track valid component pairs by setting the IDs to -1 or something else > invalid. This is just an improvement on my "option 1" (improved because all-ones for the component ID is going to be invalid for sure, while all zeroes could be a valid component). > > All those component IDs which have remained invalid after the error_inject > write happens, get ignored - you gather only those which are valid and inject. Or just stop collecting on the first invalid one. > And this way you can keep the old values too and gather them again and inject > again, over and over again. > > Right? Yup. -Tony
