On Mon, Jun 02, 2025 at 10:02:15AM -0700, Luck, Tony wrote: > 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 Thank you Tony and Borislav, this is great feedback. I will update the patches and send out a new revision that uses Tony's UI for the ID and syndrome. -Zaid
