On 1/9/23 18:23, Huang, Kai wrote: > On Mon, 2023-01-09 at 16:47 -0800, Dave Hansen wrote: >> On 1/9/23 16:40, Huang, Kai wrote: >>> On Fri, 2023-01-06 at 11:24 -0800, Dave Hansen wrote: >> ... >>>> Also, tdmr_sz and max_tdmrs can both be derived from 'sysinfo'. Do they >>>> really need to be stored here? >>> >>> It's not mandatory to keep them here. I did it mainly because I want to avoid >>> passing 'sysinfo' as argument for almost all functions related to constructing >>> TDMRs. >> >> I don't think it hurts readability that much. On the contrary, it makes >> it more clear what data is needed for initialization. > > Sorry one thing I forgot to mention is if we keep 'tdmr_sz' in 'struct > tdmr_info_list', it only needs to be calculated at once when allocating the > buffer. Otherwise, we need to calculate it based on sysinfo- > max_reserved_per_tdmr each time we want to get a TDMR at a given index. What's the problem with recalculating it? It is calculated like this: tdmr_sz = ALIGN(constant1 + constant2 * variable); So, what's the problem? You're concerned about too many multiplications? > To me putting relevant fields (tdmrs, tdmr_sz, max_tdmrs, nr_consumed_tdmrs) > together makes how the TDMR list is organized more clear. But please let me > know if you prefer removing 'tdmr_sz' and 'max_tdmrs'. > > Btw, if we remove 'tdmr_sz' and 'max_tdmrs', even nr_consumed_tdmrs is not > absolutely necessary here. It can be a local variable of init_tdx_module() (as > shown in v7), and the 'struct tdmr_info_list' will only have the 'tdmrs' member > (as you commented in v7): > > https://lore.kernel.org/linux-mm/cc195eb6499cf021b4ce2e937200571915bfe66f.camel@xxxxxxxxx/T/#mb9826e2bcf8bf6399c13cc5f95a948fe4b3a46d9 > > Please let me know what's your preference? I dunno. My gut says that passing sysinfo around and just deriving the sizes values from that with helpers is the best way. 'struct tdmr_info_list' isn't a horrible idea in and of itself, but I think it's a confusing structure because it's not clear how the pieces fit together when half of it is *required* and the other half is just for some kind of perceived convenience.
