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 <[email protected]> --- .../testing/selftests/kvm/x86/hyperv_tlb_flush.c | 15 ++------------- 1 file changed, 2 insertions(+), 13 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..4b7f089542c1 100644 --- a/tools/testing/selftests/kvm/x86/hyperv_tlb_flush.c +++ b/tools/testing/selftests/kvm/x86/hyperv_tlb_flush.c @@ -141,17 +141,6 @@ 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"); -} - /* * Prepare to test: 'disable' workers by setting the expectation to '0', * clear hypercall input page and then swap two test pages. @@ -169,7 +158,7 @@ static inline void prepare_to_test(struct test_data *data) wmb(); /* Make sure workers have enough time to notice */ - do_delay(); + udelay(100); /* Swap test page mappings */ swap_two_test_pages(data->test_pages_pte[0], data->test_pages_pte[1]); @@ -189,7 +178,7 @@ static inline void post_test(struct test_data *data, u64 exp1, u64 exp2) set_expected_val((void *)data->test_pages, exp2, WORKER_VCPU_ID_2); /* Make sure workers have enough time to test */ - do_delay(); + udelay(100); } #define TESTVAL1 0x0101010101010101 -- 2.53.0
