linux-kernel - Re: [PATCH 23/70] x86/sev-es: Add support for handling IOIO exceptions

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Date:   Fri, 20 Mar 2020 23:24:27 +0100
From:   Joerg Roedel <jroedel@...e.de>
To:     David Rientjes <rientjes@...gle.com>
Cc:     Joerg Roedel <joro@...tes.org>, x86@...nel.org, hpa@...or.com,
        Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Hellstrom <thellstrom@...are.com>,
        Jiri Slaby <jslaby@...e.cz>,
        Dan Williams <dan.j.williams@...el.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Juergen Gross <jgross@...e.com>,
        Kees Cook <keescook@...omium.org>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        virtualization@...ts.linux-foundation.org
Subject: Re: [PATCH 23/70] x86/sev-es: Add support for handling IOIO
 exceptions

On Fri, Mar 20, 2020 at 02:03:17PM -0700, David Rientjes wrote:
> On Thu, 19 Mar 2020, Joerg Roedel wrote:
> > +	if (exit_info_1 & IOIO_TYPE_STR) {
> > +		int df = (regs->flags & X86_EFLAGS_DF) ? -1 : 1;
> >		[ ... ]
> > +		if (!(exit_info_1 & IOIO_TYPE_IN)) {
> > +			ret = vc_insn_string_read(ctxt,
> > +					       (void *)(es_base + regs->si),
> > +					       ghcb->shared_buffer, io_bytes,
> > +					       exit_info_2, df);
> 
> The last argument to vc_insn_string_read() is "bool backwards" which in 
> this case it appears will always be true?

Right, thanks, good catch, I'll fix this. Seems to be a leftover from a
previous version.

Regards,

	Joerg