>>> On 17.03.16 at 11:45, <andrew.coop...@citrix.com> wrote: > On 17/03/16 10:25, Jan Beulich wrote: >>>>> On 16.03.16 at 21:05, <andrew.coop...@citrix.com> wrote: >>> @@ -1742,8 +1742,10 @@ static void load_segments(struct vcpu *n) >>> cs_and_mask = (unsigned short)regs->cs | >>> ((unsigned int)vcpu_info(n, evtchn_upcall_mask) << 16); >>> /* Fold upcall mask into RFLAGS.IF. */ >>> - eflags = regs->_eflags & ~X86_EFLAGS_IF; >>> + eflags = regs->_eflags & ~(X86_EFLAGS_IF|X86_EFLAGS_IOPL); >> This and ... >> >>> @@ -1788,8 +1790,10 @@ static void load_segments(struct vcpu *n) >>> ((unsigned long)vcpu_info(n, evtchn_upcall_mask) << 32); >>> >>> /* Fold upcall mask into RFLAGS.IF. */ >>> - rflags = regs->rflags & ~X86_EFLAGS_IF; >>> + rflags = regs->rflags & ~(X86_EFLAGS_IF|X86_EFLAGS_IOPL); >> ... this is not really necessary (but also not wrong) - the actual >> EFLAGS.IOPL is always zero (and assumed to be so by code >> further down from the respective adjustments you make). For >> consistency's sake it might be better to either drop the changes >> here, or also adjust the two places masking regs->eflags. > > I will adjust the others. I would prefer not to rely on the assumption > that it is actually 0.
But you realize that if it wasn't zero, we'd have a security issue? (This notwithstanding I'm fine with both directions, as indicated before.) Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
