>>> On 02.05.18 at 17:08, <boris.ostrovsky@xxxxxxxxxx> wrote: > On 05/02/2018 11:00 AM, Jan Beulich wrote: >>>>> On 02.05.18 at 16:57, <boris.ostrovsky@xxxxxxxxxx> wrote: >>> On 05/02/2018 04:05 AM, Jan Beulich wrote: >>>>>>> On 30.04.18 at 18:23, <boris.ostrovsky@xxxxxxxxxx> wrote: >>>>> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> >>>> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx> >>>> >>>> But to understand why things have been working nevertheless it would >>>> have been nice if the commit message wasn't empty, but instead said >>>> something like "The two happen to be identical on 64-bit." >>> >>> Why do you think they are identical? __KERNEL_CS points to entry#12 >>> (which we don't specify in PVH GDT) while __BOOT_CS is the second entry >>> (which we do create). >> That's 32-bit's __KERNEL_CS. If the two weren't identical, the ljmp >> you adjust would never have worked afaict. > > > Oh, right. My theory was that we were picking up something from the > stack (which is where 12th entry would be pointing) and the L bit, which > I think is the only one we'd care about, happened to always be set there. I don't think the L bit is the only one we care about, as I don't think you can load a non-code selector into CS (even if none of the attributes are later used for anything). Jan
