[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3 4/4] x86/asm: Rewrite sync_core() to use IRET-to-self
On Tue, Dec 06, 2016 at 01:46:37AM -0700, Jan Beulich wrote: > > + asm volatile ( > > + "pushfl\n\t" > > + "pushl %%cs\n\t" > > + "pushl $1f\n\t" > > + "iret\n\t" > > + "1:" > > + : "+r" (__sp) : : "cc", "memory"); > > I don't thing EFLAGS (i.e. "cc") gets modified anywhere here. And > the memory clobber would perhaps better be pulled out into an > explicit barrier() invocation (making it more obvious what it's needed > for)? EVerything that implies a memory barrier (and I think serializing instructions do that) also imply a compiler barrier. Not doing the memory clobber gets you inconsistency wrt everything else. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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