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Message-ID: <1518392837.3979.14.camel@HansenPartnership.com>
Subject: Re: [PATCH 00/31 v2] PTI support for x86_32
From:   James Bottomley <James.Bottomley@HansenPartnership.com>
To:     Andy Lutomirski <luto@amacapital.net>
Cc:     Mark D Rustad <mrustad@gmail.com>,
        Adam Borowski <kilobyte@angband.pl>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Joerg Roedel <jroedel@suse.de>,
        Andy Lutomirski <luto@kernel.org>,
        Joerg Roedel <joro@8bytes.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@kernel.org>,
        "H . Peter Anvin" <hpa@zytor.com>, X86 ML <x86@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux-MM <linux-mm@kvack.org>,
        Dave Hansen <dave.hansen@intel.com>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Juergen Gross <jgross@suse.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Borislav Petkov <bp@alien8.de>, Jiri Kosina <jkosina@suse.cz>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Brian Gerst <brgerst@gmail.com>,
        David Laight <David.Laight@aculab.com>,
        Denys Vlasenko <dvlasenk@redhat.com>,
        Eduardo Valentin <eduval@amazon.com>,
        Greg KH <gregkh@linuxfoundation.org>,
        Will Deacon <will.deacon@arm.com>,
        "Liguori, Anthony" <aliguori@amazon.com>,
        Daniel Gruss <daniel.gruss@iaik.tugraz.at>,
        Hugh Dickins <hughd@google.com>,
        Kees Cook <keescook@google.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Waiman Long <llong@redhat.com>, Pavel Machek <pavel@ucw.cz>
Date:   Sun, 11 Feb 2018 15:47:17 -0800
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On Sun, 2018-02-11 at 14:30 -0800, Andy Lutomirski wrote:
> 
> > 
> > On Feb 11, 2018, at 2:12 PM, James Bottomley <James.Bottomley@Hanse
> > nPartnership.com> wrote:
> > 
> > > 
> > > On Sun, 2018-02-11 at 11:42 -0800, Andy Lutomirski wrote:
> > > 
> > > > 
> > > > On Feb 11, 2018, at 9:40 AM, Mark D Rustad <mrustad@gmail.com>
> > > > wrote:
> > > > 
> > > > 
> > > > > 
> > > > > 
> > > > > On Feb 11, 2018, at 2:59 AM, Adam Borowski <kilobyte@angband.
> > > > > pl>
> > > > > wrote:
> > > > > 
> > > > > > 
> > > > > > 
> > > > > > Does Debian make it easy to upgrade to a 64-bit kernel if
> > > > > > you
> > > > > > have a
> > > > > > 32-bit install?
> > > > > 
> > > > > Quite easy, yeah.  Crossgrading userspace is not for the
> > > > > faint of the heart, but changing just the kernel is fine.
> > > > 
> > > > ISTR that iscsi doesn't work when running a 64-bit kernel with
> > > > a 32-bit userspace. I remember someone offered kernel patches
> > > > to fix it, but I think they were rejected. I haven't messed
> > > > with that stuff in many years, so perhaps the userspace side
> > > > now has accommodation for it. It might be something to check
> > > > on.
> > > > 
> > > 
> > > At the risk of suggesting heresy, should we consider removing
> > > x86_32 support at some point?
> > 
> > Hey, my cloud server is 32 bit:
> > 
> > bedivere:~# cat /proc/cpuinfo 
> > processor    : 0
> > vendor_id    : GenuineIntel
> > cpu family    : 15
> > model        : 2
> > model name    : Intel(R) Pentium(R) 4 CPU 2.80GHz
> > stepping    : 9
> > microcode    : 0x2e
> > cpu MHz        : 2813.464
> > [...]
> > 
> > I suspect a lot of people are in the same position: grandfathered
> > in on an old hosting plan, but not really willing to switch to a
> > new 64 bit box because the monthly cost about doubles and nothing
> > it does is currently anywhere up to (let alone over) the capacity
> > of the single 686 processor.
> > 
> > The thing which is making me consider it is actually getting a TPM
> > to protect the private keys, but doubling the monthly cost is still
> > a huge disincentive.
> 
> Where are they hosting this?  Last I checked, replacing a P4 and
> motherboard with something new paid for itself in about a year in
> power savings.

It's a rented server not a co-lo cage.  I don't doubt it's costing the
hosting provider, but they're keeping my rates low.

James