Messages in this thread | | | From | (Eric W. Biederman) | Date | Fri, 21 Sep 2012 17:41:34 -0700 | Subject | Re: [PATCH 00/11] x86: Supervisor Mode Access Prevention |
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"H. Peter Anvin" <hpa@linux.intel.com> writes:
> On 09/21/2012 03:07 PM, Eric W. Biederman wrote: >> >> Have you tested kexec in this environment? >> >> This is the kind of cpu feature that when we enable it, frequently we >> have to do something on the kexec path. >> >> At a quick skim it looks like the kexec path is using kernel page table >> entries and clearing all bits from cr4 except X86_CR4_PAE so I don't >> actually expect this change will require anything on the kexec path. >> > > I have not, no, but as you quite correctly point out that shouldn't > affect things. > > We should also change the kernel to start clean with CR4 -- the purpose > of CR4 is to indicate which CPU features the OS is opting into. > > I think we do on x86-64 but not on x86-32 at the moment. > > This is an unrelated problem, though, and can be addressed later.
Agreed. I just was just curious where things stood.
Eric
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