diff options
Diffstat (limited to 'tools/testing/selftests/kvm/include/x86_64/svm_util.h')
| -rw-r--r-- | tools/testing/selftests/kvm/include/x86_64/svm_util.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/include/x86_64/svm_util.h b/tools/testing/selftests/kvm/include/x86_64/svm_util.h index 7aee6244ab6a..044f0f872ba9 100644 --- a/tools/testing/selftests/kvm/include/x86_64/svm_util.h +++ b/tools/testing/selftests/kvm/include/x86_64/svm_util.h @@ -32,6 +32,20 @@ struct svm_test_data { uint64_t msr_gpa; }; +static inline void vmmcall(void) +{ + /* + * Stuff RAX and RCX with "safe" values to make sure L0 doesn't handle + * it as a valid hypercall (e.g. Hyper-V L2 TLB flush) as the intended + * use of this function is to exit to L1 from L2. Clobber all other + * GPRs as L1 doesn't correctly preserve them during vmexits. + */ + __asm__ __volatile__("push %%rbp; vmmcall; pop %%rbp" + : : "a"(0xdeadbeef), "c"(0xbeefdead) + : "rbx", "rdx", "rsi", "rdi", "r8", "r9", + "r10", "r11", "r12", "r13", "r14", "r15"); +} + #define stgi() \ __asm__ __volatile__( \ "stgi\n" \ |