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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Mon, 17 Jul 2023 17:27:57 -0700
Message-ID: <CAHk-=whGm0gQhUUK0o+=rwVTNsFDkjz+6=y+NvmcYe=SCW-2JA@mail.gmail.com>
Subject: Re: [patch 00/58] x86/apic: Decrapification and static calls
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     LKML <linux-kernel@vger.kernel.org>, x86@kernel.org,
        Andrew Cooper <andrew.cooper3@citrix.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Wei Liu <wei.liu@kernel.org>,
        Arjan van de Ven <arjan@linux.intel.com>,
        Juergen Gross <jgross@suse.com>
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On Mon, 17 Jul 2023 at 16:14, Thomas Gleixner <tglx@linutronix.de> wrote:
>
> But what I really want to do is to make x86 SMP only.

I don't hate the notion, but it would make our UP coverage much worse
for other targets.

We already have weak coverage of UP builds anyway, since no sane
developer uses UP. But if we make UP not even be an option on x86,
then that coverage goes from bad to abysmal.

That said, I already floated dropping i486 support a couple of years
ago. If what you *really* want is "unconditional APIC support", then
that would be it, no?

So I don't like "force SMP" from a coverage standpoint. But if the
pain point is "we support machines that don't even have an APIC at
all", *that* I think we could just decide to do.

Hmm?

Anyway, the series looks good to me. I did have one reaction, but that
is probably due to my own confusion.

              Linus