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 15:34:25 +0200 |
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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
Thanks, /Thomas
> Something like: > > #define INSN_INL 0xed > #define INSN_VMCALL 0x0f,0x01,0xc1 > #define INSN_VMMCALL 0x0f,0x01,0xd9 > > #define VMWARE_HYPERCALL \ > ALTERNATIVE_2(_ASM_MK_NOP(INSN_INL), > _ASM_MK_NOP(INSN_VMCALL), X86_FEATURE_VMCALL, > _ASM_MK_NOP(INSN_VMMCALL), X86_FEATURE_VMMCALL) > > With possibly a patch that does 's/_ASM_MK_NOP/_ASM_MK_INSN/' on > arch/x86/ for further sanity :-)
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