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Date:   Thu, 20 Aug 2020 12:21:18 -0500
From:   Josh Poimboeuf <jpoimboe@redhat.com>
To:     Andy Lutomirski <luto@amacapital.net>
Cc:     peterz@infradead.org, Brian Gerst <brgerst@gmail.com>,
        the arch/x86 maintainers <x86@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Kyle Huey <me@kylehuey.com>,
        Alexandre Chartre <alexandre.chartre@oracle.com>,
        Robert O'Callahan <rocallahan@gmail.com>,
        "Paul E. McKenney" <paulmck@kernel.org>,
        Frederic Weisbecker <frederic@kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Petr Mladek <pmladek@suse.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Joel Fernandes <joel@joelfernandes.org>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Juergen Gross <jgross@suse.com>,
        Andy Lutomirski <luto@kernel.org>
Subject: Re: [RFC][PATCH 4/7] x86/debug: Move historical SYSENTER junk into
 exc_debug_kernel()
Message-ID: <20200820172118.n5injemo3ic63x6j@treble>
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 <156769F5-0BCC-4FB8-A56D-0E92601F558A@amacapital.net>
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On Thu, Aug 20, 2020 at 09:43:15AM -0700, Andy Lutomirski wrote:
> 
> 
> > On Aug 20, 2020, at 9:35 AM, peterz@infradead.org wrote:
> > 
> > ﻿On Thu, Aug 20, 2020 at 11:17:29AM -0500, Josh Poimboeuf wrote:
> >> On Thu, Aug 20, 2020 at 05:21:11PM +0200, peterz@infradead.org wrote:
> > 
> >>> qemu-gdb stub should eat the event before it lands in the guest
> >> 
> >> Are we sure about that?  I triggered the warning just now, stepping
> >> through the debug handler.
> > 
> > Not sure at all, that's what seemed reasonable, but since when did that
> > stop virt ;-)
> > 
> > Also, can you trigger that same with upstream? Because I suspect this
> > ought to tickle the old code too.
> 
> I’ve lost track of how many bugs QEMU and KVM have in this space.
> Let’s keep it as a warning, but a bug. But let’s get rid of the
> totally bogus TIF_SINGLESTEP manipulation.

By "but a bug", I assume you mean "not a bug" :-)

-- 
Josh