[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3 08/18] x86emul: support {,V}MOVNTDQA
>>> On 20.02.17 at 16:01, <andrew.cooper3@xxxxxxxxxx> wrote: > On 15/02/17 11:12, Jan Beulich wrote: >> @@ -6806,6 +6808,23 @@ x86_emulate( >> sfence = true; >> break; >> >> + case X86EMUL_OPC_66(0x0f38, 0x2a): /* movntdqa m128,xmm */ >> + case X86EMUL_OPC_VEX_66(0x0f38, 0x2a): /* vmovntdqa mem,{x,y}mm */ >> + generate_exception_if(ea.type != OP_MEM, EXC_UD); >> + /* Ignore the non-temporal hint for now, using movdqa instead. */ >> + asm volatile ( "mfence" ::: "memory" ); > > Similarly for the sfence question in patch 3, why do we need to care > here? The guest will have had to execute mfence prior to movntdqa > trapping for emulation if it cared. We use MOVDQA for the emulation, so again to be on the safe side against errata, we better issue a fence up front. Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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