[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 2/7] Clear AC bit in RFLAGS to protect Xen itself by SMAP
> -----Original Message----- > From: Jan Beulich [mailto:JBeulich@xxxxxxxx] > Sent: Thursday, April 24, 2014 7:37 PM > To: Andrew Cooper; Wu, Feng > Cc: ian.campbell@xxxxxxxxxx; Dong, Eddie; Nakajima, Jun; Tian, Kevin; > xen-devel@xxxxxxxxxxxxx > Subject: Re: [PATCH v2 2/7] Clear AC bit in RFLAGS to protect Xen itself by > SMAP > > >>> On 24.04.14 at 12:51, <andrew.cooper3@xxxxxxxxxx> wrote: > > On 24/04/14 08:20, Wu, Feng wrote: > >>> From: Jan Beulich [mailto:JBeulich@xxxxxxxx] > >>>>>> On 24.04.14 at 08:45, <feng.wu@xxxxxxxxx> wrote: > >>>>> From: Andrew Cooper [mailto:andrew.cooper3@xxxxxxxxxx] > >>>>> On 23/04/14 15:35, Feng Wu wrote: > >>>>>> @@ -268,6 +269,7 @@ bad_hypercall: > >>>>>> jmp test_all_events > >>>>>> > >>>>>> ENTRY(sysenter_entry) > >>>>>> + ASM_CLAC > >>>>>> sti > >>>>>> pushq $FLAT_USER_SS > >>>>>> pushq $0 > >>> Looking at this again, btw, makes me thing that the clac should go > >>> after the sti here. > > > > It must be after sysenter_eflags_saved, or we will erroneously clear the > > AC flag from the flags used to restore guest context. > > Indeed, and not just AC considering that the macro right now involves > a conditional branch. > Thanks for your comments, I will change this, which may involve bugs here. > Jan Thanks, Feng _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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