lkml.org 
[lkml]   [2018]   [Jul]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 1/5 V5] Add a function(ioremap_encrypted) for kdump when AMD sme enabled
From
Date
在 2018年07月03日 17:39, Borislav Petkov 写道:
> On Tue, Jul 03, 2018 at 10:17:19AM +0800, lijiang wrote:
>> for example, the elfcorehdr. In fact, the elfcorehdr and notes
>
> You mean this?
>
> ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
> {
> - return read_from_oldmem(buf, count, ppos, 0);
> + return read_from_oldmem(buf, count, ppos, 0, sme_active());
>
> That looks encrypted to me.
>
The elf notes is an old memory, it is encrypted.

But the elf header is a crash kernel reserved memory, which is unencrypted.
ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
{
- return read_from_oldmem(buf, count, ppos, 0);
+ return read_from_oldmem(buf, count, ppos, 0, false);
}

They call the same function(read_from_oldmem->ioremap_cache), so it is hard to
properly remap the memory if we don't use the parameter to distinguish.

Regards,
Lianbo
>> call the same function(read_from_oldmem->ioremap_cache), in this case,
>> it is very difficult to properly remap the memory if the caller don't
>> care whether the memory is encrypted.
>
> So beef up the logic in __ioremap_caller() to figure out based on the
> address whether to access the memory encrypted or not. You can find out
> the elfcorehdr address in the capture kernel.
>

\
 
 \ /
  Last update: 2018-07-03 13:26    [W:0.100 / U:2.312 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site