[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] x86/xen: Fix 32-bit PV guests's usage of kernel_stack
On 09/04/14 15:21, Jan Beulich wrote: >>>> On 09.04.14 at 16:06, <boris.ostrovsky@xxxxxxxxxx> wrote: >> --- a/arch/x86/xen/xen-asm_32.S >> +++ b/arch/x86/xen/xen-asm_32.S >> @@ -88,7 +88,11 @@ ENTRY(xen_iret) >> * avoid having to reload %fs >> */ >> #ifdef CONFIG_SMP >> + pushw %fs >> + movl $(__KERNEL_PERCPU), %eax >> + movl %eax, %fs >> GET_THREAD_INFO(%eax) >> + popw %fs > > I don't think it's guaranteed that this can't fault. If loading %fs faults when it is restored previously, the fixup zeros the value. However, this later load could still fault even if the first succeeded. Suggest copying the fixup section from the RESTORE_REGS macros in arch/x86/kernel/entry_32.S David _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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