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    SubjectRe: [PATCH 06/24] x86,kvm: Fix indirect calls in emulator
    On Tue, Jan 23, 2018 at 08:48:13PM +0000, David Woodhouse wrote:
    > On Tue, 2018-01-23 at 21:28 +0100, Borislav Petkov wrote:
    > >
    > > >       flags = (flags & EFLAGS_MASK) | X86_EFLAGS_IF;
    > > > -     asm("push %[flags]; popf; call *%[fastop]"
    > > > -         : "=a"(rc) : [fastop]"r"(fop), [flags]"r"(flags));
    > > > +     asm("push %[flags]; popf; " CALL_NOSPEC
    > > > +         : "=a"(rc) : [thunk_target]"r"(fop), [flags]"r"(flags));
    > >
    > > Oh, "thunk_target" is magical.
    >
    > You can use THUNK_TARGET(fop), which will be "rm" on 32-bit and avoids
    > register starvation in some cases (I don't think the hyperv calls
    > worked until I did that).

    The reason I didn't use THUNK_TARGET() was exactly because it used "rm"
    and the current code did "r" only. I'm happy to change if people can
    agree on something ;-)

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