This is a note to let you know that I've just added the patch titled x86/xen: add CPU dependencies for 32-bit build to the 6.6-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: x86-xen-add-cpu-dependencies-for-32-bit-build.patch and it can be found in the queue-6.6 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit ac127c1777090c83c70fa1a244e17af28b36121f Author: Arnd Bergmann <arnd@xxxxxxxx> Date: Mon Dec 4 09:47:01 2023 +0100 x86/xen: add CPU dependencies for 32-bit build [ Upstream commit 93cd0597649844a0fe7989839a3202735fb3ae67 ] Xen only supports modern CPUs even when running a 32-bit kernel, and it now requires a kernel built for a 64 byte (or larger) cache line: In file included from <command-line>: In function 'xen_vcpu_setup', inlined from 'xen_vcpu_setup_restore' at arch/x86/xen/enlighten.c:111:3, inlined from 'xen_vcpu_restore' at arch/x86/xen/enlighten.c:141:3: include/linux/compiler_types.h:435:45: error: call to '__compiletime_assert_287' declared with attribute error: BUILD_BUG_ON failed: sizeof(*vcpup) > SMP_CACHE_BYTES arch/x86/xen/enlighten.c:166:9: note: in expansion of macro 'BUILD_BUG_ON' 166 | BUILD_BUG_ON(sizeof(*vcpup) > SMP_CACHE_BYTES); | ^~~~~~~~~~~~ Enforce the dependency with a whitelist of CPU configurations. In normal distro kernels, CONFIG_X86_GENERIC is enabled, and this works fine. When this is not set, still allow Xen to be built on kernels that target a 64-bit capable CPU. Fixes: db2832309a82 ("x86/xen: fix percpu vcpu_info allocation") Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Reviewed-by: Juergen Gross <jgross@xxxxxxxx> Tested-by: Alyssa Ross <hi@xxxxxxxxx> Link: https://lore.kernel.org/r/20231204084722.3789473-1-arnd@xxxxxxxxxx Signed-off-by: Juergen Gross <jgross@xxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig index 9b1ec5d8c99c8..a65fc2ae15b49 100644 --- a/arch/x86/xen/Kconfig +++ b/arch/x86/xen/Kconfig @@ -9,6 +9,7 @@ config XEN select PARAVIRT_CLOCK select X86_HV_CALLBACK_VECTOR depends on X86_64 || (X86_32 && X86_PAE) + depends on X86_64 || (X86_GENERIC || MPENTIUM4 || MCORE2 || MATOM || MK8) depends on X86_LOCAL_APIC && X86_TSC help This is the Linux Xen port. Enabling this will allow the