On 21/08/19 22:17, Kinney, Michael D wrote: > Paolo, > > It makes sense to match real HW.
Note that it'd also be fine to match some kind of official Intel specification even if no processor (currently?) supports it. > That puts us back to > the reset vector and handling the initial SMI at > 3000:8000. That is all workable from a FW implementation > perspective. It look like the only issue left is DMA. > > DMA protection of memory ranges is a chipset feature. > For the current QEMU implementation, what ranges of > memory are guaranteed to be protected from DMA? Is > it only A/B seg and TSEG? Yes. Paolo >> Yes, all of these would work. Again, I'm interested in >> having something that has a hope of being implemented in >> real hardware. >> >> Another, far easier to implement possibility could be a >> lockable MSR (could be the existing >> MSR_SMM_FEATURE_CONTROL) that allows programming the >> SMBASE outside SMM. It would be nice if such a bit >> could be defined by Intel. >> >> Paolo
