Messages in this thread | | | Date | Tue, 14 Jan 2014 07:14:48 -0800 | From | "H. Peter Anvin" <> | Subject | Re: AMD errata 793 (CVE-2013-6885) needs a workaround in Linux? |
| |
On 01/14/2014 03:55 AM, Borislav Petkov wrote: > On Tue, Jan 14, 2014 at 09:41:33AM -0200, Henrique de Moraes Holschuh wrote: >> I just got this assigned to amd64-microcode in Debian, but it is something >> that needs to be worked around by the EFI/BIOS and/or the kernel. >> >> Since we all know just how well it pans out to depend on BIOS/EFI updates >> for *anything*, I'm raising the issue here. IMHO looks like it would be >> worthwhile to either set the relevant MSR in the kernel if the BIOS didn't >> do it, or at least warn the user of the need for a BIOS/EFI update... >> >> It is the usual hangs-core type of CPU errata (therefore, the best type >> since it won't cause silent data corruption). gcc-produced code managed to >> trigger it (in DragonFly BSD). > > I think this is a different issue than the dragonfly issue. In any case, > if AMD delivers all BIOS with this workaround enabled, we don't need to > do anything. And I asked them about it so we'll have an answer soon, I > hope. > > In any case, I'm on it. >
Seriously, though, if this MSR can be set at runtime without problems (which covers 98% of all workarounds, but not 100%) then it seems like a no-brainer to just do it as long as the offending CPUs can be identified by the kernel.
-hpa
| |