[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] x86_emulate adjustments
On 5/1/07 11:57, "Jan Beulich" <jbeulich@xxxxxxxxxx> wrote: >> I already got the mis-emulation of x86/64 PUSH/POP with operand-size >> override. The stacksz thing I would do differently -- extend the mode input >> field to have an extra stack-address-size field. There's another thing >> that's not right at the moment -- I think on POP we have to calculate the >> operand effective address after adjusting the stack pointer? That is broken >> right now which is not a good thing. :-) > > The patch sent actually fixes that. Oh yes, that's neat. But it should increment the effective address by op_bytes not by stacksz. stacksz only specifies the stack pointer's width, not stack data size. > I finally also want the main one fixed. And yes, there are problems with the > prefix decoding, which can possibly be ignored when emulation pv guest insns, > but which (in my opinion) should match hardware behavior 1:1 for hvm guests. I don't see any problem with the existing code w.r.t. what is architecturally supported. REX byte must come after all prefix bytes, and Intel says that only 4 prefix bytes are allowed. REPNE is not a valid prefix on any instruction that the emulator currently supports. If instructions are outside these defined boundaries we must have some scope for interpretation? -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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