Messages in this thread | | | Subject | Re: [PATCH 2/4] x86/vmware: Add a header file for hypercall definitions | From | Thomas Hellström (VMware) <> | Date | Tue, 20 Aug 2019 21:19:40 +0200 |
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On 8/20/19 3:42 PM, Thomas Gleixner wrote: > On Tue, 20 Aug 2019, Thomas Hellström (VMware) wrote: > >> On 8/20/19 1:32 PM, Peter Zijlstra wrote: >>> On Sun, Aug 18, 2019 at 04:33:14PM +0200, Thomas Hellström (VMware) wrote: >>> >>>> +#define VMWARE_HYPERCALL \ >>>> + ALTERNATIVE_2(".byte 0xed", \ >>>> + ".byte 0x0f, 0x01, 0xc1", X86_FEATURE_VMW_VMCALL, \ >>>> + ".byte 0x0f, 0x01, 0xd9", X86_FEATURE_VMW_VMMCALL) >>> For sanity, could we either add comments, or macros for those >>> instrucions? >> Hmm. Here I followed and slightly extended what was done in asm/kvm_para.h. >> >> What confuses me a bit is, if it's clarity we're after, why don't people use >> >> #define VMWARE_HYPERCALL \ >> ALTERNATIVE_2("inl (%%dx)", \ >> "vmcall", X86_FEATURE_VMW_VMCALL, \ >> "vmmcall", X86_FEATURE_VMW_VMMCALL) >> >> Seems to build fine here. Is it fear of old assemblers not supporting, for >> example vmmcall > The requirement for binutils is version >= 2.21. If 2.21 supports vmcall and > vmmcall all good. > > Thanks, > > tglx
So I tested 2.20.1 and 2.21.1 from ftp.gnu.org/gnu/binutils, and both seem to assemble (as-new) and disassemble (objdump -S) vmcall and vmmcall fine so I think we should be OK using the mnemonic format then.
Thanks,
Thomas
<https://ftp.gnu.org/gnu/binutils/>
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