[PATCH] KVM: selftests: hyperv_tlb_flush: replace NOP loop with udelay()

Piotr Zarycki
2026-04-21T17:30:20Z

Replace the open-coded NOP loop with udelay() which was added to KVM
selftests in commit 6b878cbb87bf ("KVM: selftests: Add guest udelay()
utility for x86"). The NOP loop is CPU speed dependent while udelay()
provides a deterministic delay regardless of host CPU frequency.

Signed-off-by: Piotr Zarycki <piotr.zarycki@gmail.com>
---
tools/testing/selftests/kvm/x86/hyperv_tlb_flush.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86/hyperv_tlb_flush.c b/tools/testing/selftests/kvm/x86/hyperv_tlb_flush.c
index c542cc4762b1..68ebd790ff41 100644
--- a/tools/testing/selftests/kvm/x86/hyperv_tlb_flush.c
+++ b/tools/testing/selftests/kvm/x86/hyperv_tlb_flush.c
@@ -141,15 +141,9 @@ static void swap_two_test_pages(vm_paddr_t pte_gva1, vm_paddr_t pte_gva2)
*(uint64_t *)pte_gva2 = tmp;
}

-/*
- * TODO: replace the silly NOP loop with a proper udelay() implementation.
- */
static inline void do_delay(void)
{
- int i;
-
- for (i = 0; i < 1000000; i++)
- asm volatile("nop");
+ udelay(100);
}

/*
--
2.53.0