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After commita9ef277488("x86/kvm: Fix SEV check in sev_map_percpu_data()"), there is a build error when building x86_64_defconfig with GCOV using LLVM: ld.lld: error: undefined symbol: cc_vendor >>> referenced by kvm.c >>> arch/x86/kernel/kvm.o:(kvm_smp_prepare_boot_cpu) in archive vmlinux.a which corresponds to if (cc_vendor != CC_VENDOR_AMD || !cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) return; Without GCOV, clang is able to eliminate the use of cc_vendor because cc_platform_has() evaluates to false when CONFIG_ARCH_HAS_CC_PLATFORM is not set, meaning that if statement will be true no matter what value cc_vendor has. With GCOV, the instrumentation keeps the use of cc_vendor around for code coverage purposes but cc_vendor is only declared, not defined, without CONFIG_ARCH_HAS_CC_PLATFORM, leading to the build error above. Provide a macro definition of cc_vendor when CONFIG_ARCH_HAS_CC_PLATFORM is not set with a value of CC_VENDOR_NONE, so that the first condition can always be evaluated/eliminated at compile time, avoiding the build error altogether. This is very similar to the situation prior to commitda86eb9611("x86/coco: Get rid of accessor functions"). Signed-off-by: Nathan Chancellor <nathan@kernel.org> Acked-by: Borislav Petkov (AMD) <bp@alien8.de> Message-Id: <20240202-provide-cc_vendor-without-arch_has_cc_platform-v1-1-09ad5f2a3099@kernel.org> Fixes:a9ef277488("x86/kvm: Fix SEV check in sev_map_percpu_data()", 2024-01-31) Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.