Messages in this thread |  | | Date | Wed, 24 Jan 2018 11:35:25 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 06/24] x86,kvm: Fix indirect calls in emulator |
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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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