x86/microcode: do not cache microcode if it will not be used
No relevant upstream kernel due to refactoring in 6.7 Builtin/initrd microcode will not be used the ucode loader is disabled. But currently, save_microcode_in_initrd is always performed and it accesses MSR_IA32_UCODE_REV even if dis_ucode_ldr is true, and in particular even if X86_FEATURE_HYPERVISOR is set; the TDX module does not implement the MSR and the result is a call trace at boot for TDX guests. Mainline Linux fixed this as part of a more complex rework of microcode caching that went into 6.7 (see in particular commits dd5e3e3ca6, "x86/microcode/intel: Simplify early loading"; and a7939f0167203, "x86/microcode/amd: Cache builtin/initrd microcode early"). Do the bare minimum in stable kernels, setting initrd_gone just like mainline Linux does in mark_initrd_gone(). Note that save_microcode_in_initrd() is not in the microcode application path, which runs with paging disabled on 32-bit systems, so it can (and has to) use dis_ucode_ldr instead of check_loader_disabled_ap(). Cc: stable@vger.kernel.org # v6.6+ Cc: x86@kernel.org # v6.6+ Cc: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by:Paolo Bonzini <pbonzini@redhat.com> Acked-by:
Borislav Petkov (AMD) <bp@alien8.de> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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