On 6/6/24 10:42 AM, Reinette Chatre wrote:
Create udelay() utility for x86_64 tests to match
udelay() available to ARM and RISC-V tests.
Calibrate guest frequency using the KVM_GET_TSC_KHZ ioctl()
and share it between host and guest with the new
tsc_khz global variable.
Signed-off-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
---
.../selftests/kvm/include/x86_64/processor.h | 15 +++++++++++++++
.../testing/selftests/kvm/lib/x86_64/processor.c | 8 ++++++++
2 files changed, 23 insertions(+)
diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index 8eb57de0b587..f3a5881dd821 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -23,6 +23,7 @@
extern bool host_cpu_is_intel;
extern bool host_cpu_is_amd;
+extern unsigned long tsc_khz;
/* Forced emulation prefix, used to invoke the emulator unconditionally. */
#define KVM_FEP "ud2; .byte 'k', 'v', 'm';"
@@ -815,6 +816,20 @@ static inline void cpu_relax(void)
asm volatile("rep; nop" ::: "memory");
}
+static inline void udelay(unsigned long usec)
+{
+ unsigned long cycles = tsc_khz / 1000 * usec;
+ uint64_t start, now;
+
+ start = rdtsc();
+ for (;;) {
+ now = rdtsc();
+ if (now - start >= cycles)
+ break;
+ cpu_relax();
+ }
+}
+
#define ud2() \
__asm__ __volatile__( \
"ud2\n" \
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index c664e446136b..6558fece8a36 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -25,6 +25,7 @@ vm_vaddr_t exception_handlers;
bool host_cpu_is_amd;
bool host_cpu_is_intel;
bool is_forced_emulation_enabled;
+unsigned long tsc_khz;
static void regs_dump(FILE *stream, struct kvm_regs *regs, uint8_t indent)
{
@@ -628,6 +629,13 @@ void kvm_arch_vm_post_create(struct kvm_vm *vm)
vm_sev_ioctl(vm, KVM_SEV_INIT2, &init);
}
+
+ if (kvm_has_cap(KVM_CAP_GET_TSC_KHZ)) {
+ tsc_khz = __vm_ioctl(vm, KVM_GET_TSC_KHZ, NULL);
+ if (tsc_khz < 0)
This incorrect type usage will be fixed in next version that I plan
to send on Monday.
+ tsc_khz = 0;
+ sync_global_to_guest(vm, tsc_khz);
+ }
}
void vcpu_arch_set_entry_point(struct kvm_vcpu *vcpu, void *guest_code)
Reinette
