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bh=FJtJfAG3FTj0Mp4aU87gbbrxBXFK2d65L0vZtbl5EUU=; b=f+80DY7tvDFDFMpqYfo+VClI8mvevvV8/1IE12fkdBs6LIDvgGoi5QtieMcmS3rKyN CzNU7S9DdMA5tojtgw405VtkjlH9i9Zkt2b5u5U+dH8CwkiqcY147XYKSf0prR7APpMC zlWuUd/DlOaOJjTIndzqb1KNEBbwdV3ewWN6YefcxFLVhwUK/yvZFE5sXswPctcczKDQ +kS8eZ5HTraW3dd+qkr7AGXXrPyw+IBaKSqJSGC6B47CkSoZNhCfPQsdmLl9G0aHzhlr UyfBDkC1f1R38kGmUZ62LoaGJs8RLj30YffIj41jh+9MlMXB3D26az7Q4IoN1xLpp283 PXZA== X-Gm-Message-State: AAQBX9chNyNzTPCZX4uIPkntNh/W3yR31Gasg9iDAMZvqwt5LeCJo5Cn /RYT7U1JJWqA6ImWh9jNAQNq7AWESRrjjyk2G0fPlA== X-Google-Smtp-Source: AKy350bbu/IbL3Wka1f0D6W9Vh6lenMtSIMSjr559wYIhjDOzTsWqACJo6Ttx1C3oP9g9uZtCYk7u+/jsKCz8+F5ntg= X-Received: by 2002:a17:906:730b:b0:939:a51a:dc30 with SMTP id di11-20020a170906730b00b00939a51adc30mr6103973ejc.2.1681214960402; Tue, 11 Apr 2023 05:09:20 -0700 (PDT) MIME-Version: 1.0 References: <7739b40d-d8ba-ccde-cc6c-5d9f2c93a663@msgid.tls.msk.ru> In-Reply-To: <7739b40d-d8ba-ccde-cc6c-5d9f2c93a663@msgid.tls.msk.ru> From: Peter Maydell Date: Tue, 11 Apr 2023 13:09:03 +0100 Message-ID: Subject: Re: xen bits broke x32 build To: Michael Tokarev Cc: Joao Martins , QEMU Developers , David Woodhouse Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=2a00:1450:4864:20::631; envelope-from=peter.maydell@linaro.org; helo=mail-ej1-x631.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Tue, 11 Apr 2023 at 12:57, Michael Tokarev wrote: > > 01.04.2023 11:40, Michael Tokarev wrote: > > After bringing in xen guest support, qemu fails to build on x32: > > > > target/i386/kvm/xen-emu.c:876:5: note: in expansion of macro =E2=80=98q= emu_build_assert=E2=80=99 > > 876 | qemu_build_assert(sizeof(struct vcpu_info) =3D=3D 64); > > | ^~~~~~~~~~~~~~~~~ > > > > This one should be easy to fix, but I wonder if there are other issues > > with x32 exists.. > > Ok, I took a look at how to disable this new XEN stuff on x32. > > It is the commit 820c1aba519bd072ac71c754733f6c86d8b4309 "xen: add > CONFIG_XEN_BUS and CONFIG_XEN_EMU options for Xen emulation" adding > this construct to hw/i386/Kconfig: > > config XEN_EMU > bool > default y > depends on KVM && (I386 || X86_64) > > Since meson does not know about x32, and while ./conifgure does, it > is not propagated to meson, and sure not propagated to Kconfig too, > there's some more work needed to disable XEN_EMU on x32. Frankly I would prefer to just say "we don't support x32". It's a weird non-standard configuration that as far as I'm aware is very little used. Its stats in the debian popularity-contest graphs peaked at 18 users in 2017, and have mostly been fluctuating between 1 and 3 for the last couple of years: https://popcon.debian.org/stat/sub-x32.png We're currently planning to deprecate-and-drop 32-bit x86 hosts, which are much more widely used than this. I see no reason why we should care about this oddball failed experiment of an ABI... thanks -- PMM