Re: [Qemu-devel] [PATCHv2 0/4] Set eflags prior to segments; fix cpl in SMM

[Paolo Bonzini]

Il 29/04/2014 22:37, Kevin O'Connor ha scritto:
> This patch series is an update to the patch I sent at:
>
> https://lists.gnu.org/archive/html/qemu-devel/2014-04/msg04028.html
>
> The goal of the patch series is to fix the SMM handler so that it runs
> with the proper cpl.  I've broken the series up based on the feedback
> from Paolo.
>
> As with the previous patch, this series moves cr0 and eflags changes
> above cpu_x86_load_seg_cache() calls as cpu_x86_load_seg_cache()
> inspects those flags.  I didn't move the eflags setting in
> helper_ret_protected() because I don't think I can easily move the
> eflags logic (it's not clear to me that it is safe to change eflags
> prior to exception checks) and helper_ret_protected() doesn't change
> any eflags bits that cpu_x86_load_seg_cache() cares about.
>
> That said, continuing to have cpu_x86_load_seg_cache() depend on cr0
> and eflags is painful.  I do wonder if it would be better to calculate
> hflags lazily to eliminate these ordering issues.

Reviewed-by: Paolo Bonzini <address@hidden>

Richard, Andreas, who is going to take this?  I can do it too since I 
plan to put my soft-reset target-i386/ patches in uq/master after they 
are reviewed.

> -Kevin
>
>
> Kevin O'Connor (4):
>   Set eflags prior to calling svm_load_seg_cache() in svm_helper.c.
>   Set eflags and cr0 prior to calling cpu_x86_load_seg_cache() in
>     smm_helper.c.
>   Set eflags prior to calling cpu_x86_load_seg_cache() in seg_helper.c.
>   The x86 CPL is stored in CS.selector - auto update hflags accordingly.
>
>  bsd-user/main.c          |  2 --
>  linux-user/main.c        |  2 --
>  target-i386/cpu.h        | 25 +++++++++++------------
>  target-i386/seg_helper.c | 53 +++++++++++++++++-------------------------------
>  target-i386/smm_helper.c | 34 +++++++++++++++----------------
>  target-i386/svm_helper.c | 11 ++--------
>  6 files changed, 50 insertions(+), 77 deletions(-)