On Wed, Jan 15, 2020 at 08:46:04PM +0200, Jari Ruusu wrote: > On 1/15/20, Luis Chamberlain <mcgrof@xxxxxxxxxx> wrote: > > On Mon, Jan 13, 2020 at 09:58:25PM +0200, Jari Ruusu wrote: > >> Before that 16-byte alignment patch was applied, my only one > >> microcode built-in BLOB was "accidentally" 16-byte aligned. > > > > How did it accidentially get 16-byte aligned? > > Old code aligned it to 8-bytes. > There is 50/50-chance of it also being 16-byte aligned. But *how? Why is there a 50/50 chance of it being aligned to 16 bytes if 8 bytes are currently specified? > So it ended up being both 8-byte and 16-byte aligned. What do you mean both? How can it be aligned to both? > > Also, how do you *know* something is broken right now? > > I haven't spotted brokenness in Linux microcode loader other > than that small alignment issue. > > However, I can confirm that there are 2 microcode updates newer > than what my laptop computer's latest BIOS includes. Both newer > ones (20191115 and 20191112) are unstable on my laptop computer > i5-7200U (fam 6 model 142 step 9 pf 0x80). Hard lockups with both > of them. Back to BIOS microcode for now. I was more interested in how you are *certain*, other than manualcode inspection, and that a spec indicates we should use 16 bytes for Intel microcode -- that the 8 byte alignment *does* not allow users to currently update their Intel CPU microcode for built-in firmware. >From what I gather so far we have no case yet reported where we know for sure it fails right now with the 8 byte alignment on 64-bit. This information would just be useful for the commit log. Luis
