Messages in this thread | | | Date | Thu, 21 Jan 2021 17:58:45 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH v1 11/19] x86/sev-es: Convert to insn_decode() |
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On Mon, Dec 28, 2020 at 11:15:11AM -0800, Sean Christopherson wrote: > Alternatively, could the kernel case use insn_decode_regs()? If > vc_fetch_insn_kernel() were also modified to mirror insn_fetch_from_user(), the > two code paths could be unified except for the the fetch and the PFEC. E.g.
Personal Firearms Eligibility Check?
In any case, I prefer simple, easy to follow code at a quick glance. Stuff like...
> > static int vc_fetch_insn_kernel(struct es_em_ctxt *ctxt, > unsigned char *buffer) > { > if (copy_from_kernel_nofault(buffer, (unsigned char *)ctxt->regs->ip, MAX_INSN_SIZE)) > return 0; > > return MAX_INSN_SIZE; > } > > static enum es_result vc_decode_insn(struct es_em_ctxt *ctxt) > { > char buffer[MAX_INSN_SIZE]; > int nbytes; > > if (user_mode(ctxt->regs)) > nbytes = insn_fetch_from_user(ctxt->regs, buffer); > else > nbytes = vc_fetch_insn_kernel(ctxt, buffer); > > if (!nbytes) { > ctxt->fi.vector = X86_TRAP_PF; > ctxt->fi.error_code = X86_PF_INSTR; > if (user_mode(ctxt->regs))
... this second repeated check here is not what I would call that.
But this is my personal preference only so it's up for a vote now.
:-)
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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