diff options
Diffstat (limited to 'tools/testing/selftests/kvm/include/x86/processor.h')
| -rw-r--r-- | tools/testing/selftests/kvm/include/x86/processor.h | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/include/x86/processor.h b/tools/testing/selftests/kvm/include/x86/processor.h index 8de7cace1fbf..b89e1a6444f4 100644 --- a/tools/testing/selftests/kvm/include/x86/processor.h +++ b/tools/testing/selftests/kvm/include/x86/processor.h @@ -1335,6 +1335,46 @@ static inline void kvm_hypercall_map_gpa_range(uint64_t gpa, uint64_t size, GUEST_ASSERT(!ret); } +/* + * Execute HLT in an STI interrupt shadow to ensure that a pending IRQ that's + * intended to be a wake event arrives *after* HLT is executed. Modern CPUs, + * except for a few oddballs that KVM is unlikely to run on, block IRQs for one + * instruction after STI, *if* RFLAGS.IF=0 before STI. Note, Intel CPUs may + * block other events beyond regular IRQs, e.g. may block NMIs and SMIs too. + */ +static inline void safe_halt(void) +{ + asm volatile("sti; hlt"); +} + +/* + * Enable interrupts and ensure that interrupts are evaluated upon return from + * this function, i.e. execute a nop to consume the STi interrupt shadow. + */ +static inline void sti_nop(void) +{ + asm volatile ("sti; nop"); +} + +/* + * Enable interrupts for one instruction (nop), to allow the CPU to process all + * interrupts that are already pending. + */ +static inline void sti_nop_cli(void) +{ + asm volatile ("sti; nop; cli"); +} + +static inline void sti(void) +{ + asm volatile("sti"); +} + +static inline void cli(void) +{ + asm volatile ("cli"); +} + void __vm_xsave_require_permission(uint64_t xfeature, const char *name); #define vm_xsave_require_permission(xfeature) \ |