linux-kernel - Re: [PATCH v2 0/4] Remove 32-bit Xen PV guest support

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Date:   Thu, 2 Jul 2020 10:48:48 -0400
From:   Brian Gerst <brgerst@...il.com>
To:     Juergen Gross <jgross@...e.com>
Cc:     xen-devel <xen-devel@...ts.xenproject.org>,
        "the arch/x86 maintainers" <x86@...nel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux Virtualization <virtualization@...ts.linux-foundation.org>,
        Andy Lutomirski <luto@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Stefano Stabellini <sstabellini@...nel.org>,
        Deep Shah <sdeep@...are.com>,
        "VMware, Inc." <pv-drivers@...are.com>
Subject: Re: [PATCH v2 0/4] Remove 32-bit Xen PV guest support

On Wed, Jul 1, 2020 at 7:07 AM Juergen Gross <jgross@...e.com> wrote:
>
> The long term plan has been to replace Xen PV guests by PVH. The first
> victim of that plan are now 32-bit PV guests, as those are used only
> rather seldom these days. Xen on x86 requires 64-bit support and with
> Grub2 now supporting PVH officially since version 2.04 there is no
> need to keep 32-bit PV guest support alive in the Linux kernel.
> Additionally Meltdown mitigation is not available in the kernel running
> as 32-bit PV guest, so dropping this mode makes sense from security
> point of view, too.

One thing that you missed is removing VDSO_NOTE_NONEGSEG_BIT from
vdso32/note.S.  With that removed there is no difference from the
64-bit version.

Otherwise this series looks good to me.
--
Brian Gerst