[Bug 211467] Regression affecting 32->64 bit SYSENTER on AMD

[bugzilla-daemon@bugzilla.kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=211467

jonny5532 (jonny@magicstring.co.uk) changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
 Attachment #294993|0                           |1
        is obsolete|                            |

--- Comment #3 from jonny5532 (jonny@magicstring.co.uk) ---
Created attachment 295027
  --> https://bugzilla.kernel.org/attachment.cgi?id=295027&action=edit
Patch with whitespace fix and SOB

Thanks for confirming, here's the same patch again without the missing newline
and with my SOB tacked on the bottom. I am indeed not set up for sending
patches so would appreciate it if you could do that bit.

I had a look through emulate.c to see if I could foresee any unintended side
effects - it seems that SYSEXIT already handles the potential transition back
from 64->32 bits. 

I do note that some of the transitions to PROT64 are wrapped in "#ifdef
CONFIG_X86_64 ... #endif", for example in em_syscall. However that looks pretty
dubious in itself - if em_syscall gets run with the guest in long mode, on a 32
bit kernel, then it'll just fail to update the EIP but carry on regardless.
Probably an unlikely scenario however (KVM on AMD has only ever worked on 64
bit procs as I understand).

-- 
You may reply to this email to add a comment.

You are receiving this mail because:
You are watching the assignee of the bug.