On Mon, Jul 26, 2021, Nadav Amit wrote: > > > On Jul 19, 2021, at 9:37 PM, Reiji Watanabe <reijiw@xxxxxxxxxx> wrote: > > > > On Tue, Jul 13, 2021 at 9:35 AM Sean Christopherson <seanjc@xxxxxxxxxx> wrote: > >> > >> Preserve CR0.CD and CR0.NW on INIT instead of forcing them to '1', as > >> defined by both Intel's SDM and AMD's APM. > >> > >> Note, current versions of Intel's SDM are very poorly written with > >> respect to INIT behavior. Table 9-1. "IA-32 and Intel 64 Processor > >> States Following Power-up, Reset, or INIT" quite clearly lists power-up, > >> RESET, _and_ INIT as setting CR0=60000010H, i.e. CD/NW=1. But the SDM > >> then attempts to qualify CD/NW behavior in a footnote: > >> > >> 2. The CD and NW flags are unchanged, bit 4 is set to 1, all other bits > >> are cleared. > >> > >> Presumably that footnote is only meant for INIT, as the RESET case and > >> especially the power-up case are rather non-sensical. Another footnote > >> all but confirms that: > >> > >> 6. Internal caches are invalid after power-up and RESET, but left > >> unchanged with an INIT. > >> > >> Bare metal testing shows that CD/NW are indeed preserved on INIT (someone > >> else can hack their BIOS to check RESET and power-up :-D). > >> > >> Reported-by: Reiji Watanabe <reijiw@xxxxxxxxxx> > >> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> > > > > Reviewed-by: Reiji Watanabe <reijiw@xxxxxxxxxx> > > > > Thank you for the fix and checking the CD/NW with the bare metal testing. > > Interesting. > > Is there a kvm-unit-test to reproduce the issue by any chance? No :-/
