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From: Peter Maydell <peter.maydell@linaro.org>
To: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: "Thomas Huth" <thuth@redhat.com>,
	"Philippe Mathieu-Daudé" <philmd@linaro.org>,
	qemu-devel@nongnu.org, "Daniel Berrange" <berrange@redhat.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Markus Armbruster" <armbru@redhat.com>,
	"Alex Bennée" <alex.bennee@linaro.org>,
	qemu-arm@nongnu.org, "Maxim Levitsky" <mlevitsk@redhat.com>,
	libvir-list@redhat.com,
	"Richard Henderson" <richard.henderson@linaro.org>,
	xen-devel@lists.xenproject.org,
	"Reinoud Zandijk" <reinoud@netbsd.org>,
	"Michael Tokarev" <mjt@tls.msk.ru>,
	"Helge Deller" <deller@gmx.de>
Subject: Re: [PATCH v2 0/6] Deprecate support for 32-bit x86 and arm hosts
Date: Fri, 3 Mar 2023 11:24:46 +0000	[thread overview]
Message-ID: <CAFEAcA9cE087cowTodqAb2mkzGxxnAcBGZsMNu6uj_Nsa2v-dw@mail.gmail.com> (raw)
In-Reply-To: <89fd1c916b6c8094ea1a7a52396b3f91025c75c1.camel@physik.fu-berlin.de>

On Fri, 3 Mar 2023 at 11:09, John Paul Adrian Glaubitz
<glaubitz@physik.fu-berlin.de> wrote:
>
> Hello!
>
> On Fri, 2023-03-03 at 10:48 +0100, Thomas Huth wrote:
> > x86 ==> deprecate both, user and system emulation support on
> >          32-bit hosts
> > arm ==> deprecate only system emulation on 32-bit hosts.
>
> I would recommend against dropping support for 32-bit hosts for qemu-user
> as there are some cases where the emulation of 32-bit user code on 64-bit
> hosts does not work properly [1].
>
> Adrian
>
> > [1] https://sourceware.org/bugzilla/show_bug.cgi?id=23960

I failed entirely to get any traction with persuading the
kernel folks to provide an API to let QEMU work in that
"32-bit guest wants a 32-bit dirent but the kernel is
providing a 64-bit hash value as a dirent" case. Somebody kindly
wrote some kernel patches but they went absolutely nowhere.

It seems to only happen for certain kinds of 32-bit guest, where
the guest libc is not also using 64-bit dirents. So at least as
far as Arm guests are concerned the effective result was "the
older arm binaries that were built to need a 32-bit dirent are
just not around any more, so very few people run into the problem".
You can also work around it by using a different host filesystem
type, I think.

thanks
-- PMM


      parent reply	other threads:[~2023-03-03 11:25 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-02 16:31 [PATCH v2 0/6] Deprecate support for 32-bit x86 and arm hosts Thomas Huth
2023-03-02 16:31 ` [PATCH v2 1/6] docs/about/deprecated: Deprecate the qemu-system-i386 binary Thomas Huth
2023-03-02 18:05   ` Daniel P. Berrangé
2023-03-03  0:49     ` Wilfred Mallawa
2023-03-02 16:31 ` [PATCH v2 2/6] docs/about/deprecated: Deprecate 32-bit x86 hosts Thomas Huth
2023-03-02 18:05   ` Daniel P. Berrangé
2023-03-03  0:52   ` Wilfred Mallawa
2023-03-02 16:31 ` [PATCH v2 3/6] gitlab-ci.d/crossbuilds: Drop the i386 jobs Thomas Huth
2023-03-02 18:07   ` Daniel P. Berrangé
2023-03-03  0:53   ` Wilfred Mallawa
2023-03-02 16:31 ` [PATCH v2 4/6] docs/about/deprecated: Deprecate the qemu-system-arm binary Thomas Huth
2023-03-02 18:07   ` Daniel P. Berrangé
2023-03-02 22:16   ` Philippe Mathieu-Daudé
2023-03-03  7:36     ` Thomas Huth
2023-03-03  0:55   ` Wilfred Mallawa
2023-03-03 11:16   ` Peter Maydell
2023-03-03 11:31     ` Thomas Huth
2023-03-03 11:39       ` Daniel P. Berrangé
2023-03-02 16:31 ` [PATCH v2 5/6] docs/about/deprecated: Deprecate 32-bit arm hosts Thomas Huth
2023-03-02 18:09   ` Daniel P. Berrangé
2023-03-03  0:57   ` Wilfred Mallawa
2023-03-02 16:31 ` [PATCH v2 6/6] gitlab-ci.d/crossbuilds: Drop the 32-bit arm system emulation jobs Thomas Huth
2023-03-02 18:10   ` Daniel P. Berrangé
2023-03-02 21:58   ` Philippe Mathieu-Daudé
2023-03-03  0:57   ` Wilfred Mallawa
2023-03-02 22:07 ` [PATCH v2 0/6] Deprecate support for 32-bit x86 and arm hosts Philippe Mathieu-Daudé
2023-03-03  9:48   ` Thomas Huth
2023-03-03 11:09     ` John Paul Adrian Glaubitz
2023-03-03 11:22       ` Thomas Huth
2023-03-03 11:57         ` John Paul Adrian Glaubitz
2023-03-03 11:24       ` Peter Maydell [this message]

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