[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3 4/9] Clear AC bit in RFLAGS to protect Xen itself by SMAP
>>> On 28.04.14 at 05:15, <feng.wu@xxxxxxxxx> wrote: > @@ -466,6 +468,7 @@ ENTRY(dom_crash_sync_extable) > jmp asm_domain_crash_synchronous /* Does not return */ > > ENTRY(common_interrupt) > + ASM_CLAC > SAVE_ALL > movq %rsp,%rdi > callq do_IRQ > @@ -485,6 +488,7 @@ ENTRY(page_fault) > movl $TRAP_page_fault,4(%rsp) > /* No special register assumptions. */ > GLOBAL(handle_exception) > + ASM_CLAC > SAVE_ALL Did you check whether the addition wouldn't better go right into SAVE_ALL? > --- a/xen/arch/x86/x86_64/traps.c > +++ b/xen/arch/x86/x86_64/traps.c > @@ -437,8 +437,8 @@ void __devinit subarch_percpu_traps_init(void) > /* Common SYSCALL parameters. */ > wrmsr(MSR_STAR, 0, (FLAT_RING3_CS32<<16) | __HYPERVISOR_CS); > wrmsr(MSR_SYSCALL_MASK, > - X86_EFLAGS_VM|X86_EFLAGS_RF|X86_EFLAGS_NT| > - X86_EFLAGS_DF|X86_EFLAGS_IF|X86_EFLAGS_TF, > + X86_EFLAGS_VM|X86_EFLAGS_RF|X86_EFLAGS_NT|X86_EFLAGS_DF| > + X86_EFLAGS_IF|X86_EFLAGS_TF|X86_EFLAGS_AC, Please pay attention to ordering of existing accumulations like this: Here, the operands are ordered by bit position, so the addition should go at the beginning of the expression rather than the end. Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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