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a=rsa-sha256; c=relaxed/simple; d=ens-lyon.org; s=dkim; t=1788025849; bh=0j0jQMNP9Rs0OcCqzo+iiZhXE7dCLI4j6dw38FzVbvA=; h=From:To:Cc:Subject:Date:From; b=hqtLO43jExICrv5wX0SIv6vMIpfBr98I7kIga8Go17uQOjnRdnl6TpwRULHkgcguI QGYE1t87cqrAowpvbkmEbns039m5K8JaOgqhtByinWGReHTQ6yx0GZbyxJmtAZRYcR FnU4SgR7ITEs6JAUfOWM2+BojxAvTdAI7hqr5qA7OBFLJUteDOyh7qLiPfrM0zKkEK HKfzW7aWBkva1t0nuo2j16fw7F3OKWyP2b/f2WKnWQvBzSyeONUo2cWj87srYhfueG U0b/8S0jwayhtK9d4u3RPitDy7kHLQhBLq2+CtVoXaVmbYWXDWlwyjn9IuWhLp71fs VgJCVNZlqtF+g== From: Samuel Thibault To: qemu-devel@nongnu.org, adam@os.inf.tu-dresden.de, pbonzini@redhat.com, richard.henderson@linaro.org, mst@redhat.com Cc: Samuel Thibault Subject: [PATCH] Revert 9696846600ca ("multiboot: Prevent loading of x86_64 images") Date: Sat, 29 Aug 2026 19:50:47 +0200 Message-ID: <20260829175047.2710519-1-samuel.thibault@ens-lyon.org> X-Mailer: git-send-email 2.53.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists1p.gnu.org; Received-SPF: pass client-ip=140.77.166.138; envelope-from=SRS0=SizC=GW=ens-lyon.org=samuel.thibault@bounce.ens-lyon.org; helo=sonata.ens-lyon.org 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, SPF_HELO_PASS=-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: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @ens-lyon.org) X-ZM-MESSAGEID: 1788025909280158500 Content-Type: text/plain; charset="utf-8" Loading x86_64 images in multiboot was disabled on the ground that since multiboot actually boots 64bit kernels in 32bit mode, the binary would have to be 32bit. https://lists.gnu.org/archive/html/qemu-devel/2010-08/msg00913.html But making the binary 32bit makes using debugging tools such as gdb unnecessarily complex since they don't understand what architecture the kernel actually is. Letting qemu load x86_64 images and boot them in 32bit mode is completely fine, works, and is what the multiboot standard actually expects. This notably fixes loading gnumach in x86_64 mode. Signed-off-by: Samuel Thibault --- hw/i386/multiboot.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/hw/i386/multiboot.c b/hw/i386/multiboot.c index d544b62afb..004d5185fb 100644 --- a/hw/i386/multiboot.c +++ b/hw/i386/multiboot.c @@ -196,11 +196,6 @@ int load_multiboot(X86MachineState *x86ms, int kernel_size; fclose(f); =20 - if (((struct elf64_hdr*)header)->e_machine =3D=3D EM_X86_64) { - error_report("Cannot load x86-64 image, give a 32bit one."); - exit(1); - } - kernel_size =3D load_elf(kernel_filename, NULL, NULL, NULL, &elf_e= ntry, &elf_low, &elf_high, NULL, ELFDATA2LSB, I386_ELF_MACHINE, 0, 0); --=20 2.53.0