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| author | Nathan Chancellor <natechancellor@gmail.com> | 2020-12-18 23:37:11 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-01-07 18:07:27 -0500 |
| commit | f65cf84ee769767536dc367acc9568ddb6e4c9f4 (patch) | |
| tree | 667ca11d2d92c3e74c4abdef4b327691c61b615f | |
| parent | bc351f07260533cc1b3987339551decd00ddd52e (diff) | |
| download | linux-f65cf84ee769767536dc367acc9568ddb6e4c9f4.tar.bz2 | |
KVM: SVM: Add register operand to vmsave call in sev_es_vcpu_load
When using LLVM's integrated assembler (LLVM_IAS=1) while building
x86_64_defconfig + CONFIG_KVM=y + CONFIG_KVM_AMD=y, the following build
error occurs:
$ make LLVM=1 LLVM_IAS=1 arch/x86/kvm/svm/sev.o
arch/x86/kvm/svm/sev.c:2004:15: error: too few operands for instruction
asm volatile(__ex("vmsave") : : "a" (__sme_page_pa(sd->save_area)) : "memory");
^
arch/x86/kvm/svm/sev.c:28:17: note: expanded from macro '__ex'
#define __ex(x) __kvm_handle_fault_on_reboot(x)
^
./arch/x86/include/asm/kvm_host.h:1646:10: note: expanded from macro '__kvm_handle_fault_on_reboot'
"666: \n\t" \
^
<inline asm>:2:2: note: instantiated into assembly here
vmsave
^
1 error generated.
This happens because LLVM currently does not support calling vmsave
without the fixed register operand (%rax for 64-bit and %eax for
32-bit). This will be fixed in LLVM 12 but the kernel currently supports
LLVM 10.0.1 and newer so this needs to be handled.
Add the proper register using the _ASM_AX macro, which matches the
vmsave call in vmenter.S.
Fixes: 861377730aa9 ("KVM: SVM: Provide support for SEV-ES vCPU loading")
Link: https://reviews.llvm.org/D93524
Link: https://github.com/ClangBuiltLinux/linux/issues/1216
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Message-Id: <20201219063711.3526947-1-natechancellor@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/x86/kvm/svm/sev.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 9858d5ae9ddd..563ced07b0b8 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -2001,7 +2001,7 @@ void sev_es_vcpu_load(struct vcpu_svm *svm, int cpu) * of which one step is to perform a VMLOAD. Since hardware does not * perform a VMSAVE on VMRUN, the host savearea must be updated. */ - asm volatile(__ex("vmsave") : : "a" (__sme_page_pa(sd->save_area)) : "memory"); + asm volatile(__ex("vmsave %0") : : "a" (__sme_page_pa(sd->save_area)) : "memory"); /* * Certain MSRs are restored on VMEXIT, only save ones that aren't |