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    SubjectRe: [PATCH v3] x86-64/Xen: fix stack switching
    On Tue, Jan 15, 2019 at 8:58 AM Jan Beulich <JBeulich@suse.com> wrote:
    >
    > While in the native case entry into the kernel happens on the trampoline
    > stack, PV Xen kernels get entered with the current thread stack right
    > away. Hence source and destination stacks are identical in that case,
    > and special care is needed.
    >
    > Other than in sync_regs() the copying done on the INT80 path isn't
    > NMI / #MC safe, as either of these events occurring in the middle of the
    > stack copying would clobber data on the (source) stack.
    >
    > I'm not altering the similar code in interrupt_entry() and nmi(), as
    > those code paths are unreachable afaict when running PV Xen guests.


    Acked-by: Andy Lutomirski <luto@kernel.org>

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