Messages in this thread | | | Date | Fri, 21 Jun 2013 09:42:35 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH -v2 0/4] EFI 1:1 mapping |
| |
On 06/21/2013 07:21 AM, Borislav Petkov wrote: > On Fri, Jun 21, 2013 at 03:05:30AM -0700, H. Peter Anvin wrote: >> If you cap it you are basically imposing a constraint on the firmware >> and may not run properly (or at least have to turn off EFI runtime >> calls with all that implies.) > > I don't want to cap EFI just for the fun of it but rather set a limit > so that the next one who wants a chunk of the virtual address space can > have a reliable limit from where she/he can start. Otherwise we won't > know where EFI reliably ends... >
We don't... and I don't think there is anything we can do about it. If some messed-up firmware wants to map a terabyte we either refuse and don't allow EFI runtime calls on that machine or we accept it.
Fortunately the space is extremely large and with growing down from a known address it is less likely that we'll conflict with something.
>> It might be good to have a sanity check but it needs to be pretty >> generous. > > 64 Gb generous enough?
Let's start there and see if we run into something that gives us trouble.
-hpa
| |