Re: [PATCH] KVM: selftests: Move vcpu_args_set into perf_test_util

[Paolo Bonzini <pbonzini@redhat.com>]

On 05/08/21 19:28, David Matlack wrote:
> perf_test_util is used to set up KVM selftests where vCPUs touch a
> region of memory. The guest code is implemented in perf_test_util.c (not
> the calling selftests). The guest code requires a 1 parameter, the
> vcpuid, which has to be set by calling vcpu_args_set(vm, vcpu_id, 1,
> vcpu_id).
> 
> Today all of the selftests that use perf_test_util are making this call.
> Instead, perf_test_util should just do it. This will save some code but
> more importantly prevents mistakes since totally non-obvious that this
> needs to be called and failing to do so results in vCPUs not accessing
> the right regions of memory.
> 
> Signed-off-by: David Matlack <dmatlack@google.com>

Queued, thanks.

Paolo

> ---
>   tools/testing/selftests/kvm/access_tracking_perf_test.c        | 2 --
>   tools/testing/selftests/kvm/demand_paging_test.c               | 1 -
>   tools/testing/selftests/kvm/dirty_log_perf_test.c              | 1 -
>   tools/testing/selftests/kvm/lib/perf_test_util.c               | 2 ++
>   tools/testing/selftests/kvm/memslot_modification_stress_test.c | 1 -
>   5 files changed, 2 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/access_tracking_perf_test.c b/tools/testing/selftests/kvm/access_tracking_perf_test.c
> index e2baa187a21e..72714573ba4f 100644
> --- a/tools/testing/selftests/kvm/access_tracking_perf_test.c
> +++ b/tools/testing/selftests/kvm/access_tracking_perf_test.c
> @@ -222,8 +222,6 @@ static void *vcpu_thread_main(void *arg)
>   	int vcpu_id = vcpu_args->vcpu_id;
>   	int current_iteration = -1;
>   
> -	vcpu_args_set(vm, vcpu_id, 1, vcpu_id);
> -
>   	while (spin_wait_for_next_iteration(&current_iteration)) {
>   		switch (READ_ONCE(iteration_work)) {
>   		case ITERATION_ACCESS_MEMORY:
> diff --git a/tools/testing/selftests/kvm/demand_paging_test.c b/tools/testing/selftests/kvm/demand_paging_test.c
> index b74704305835..950f2eb634e6 100644
> --- a/tools/testing/selftests/kvm/demand_paging_test.c
> +++ b/tools/testing/selftests/kvm/demand_paging_test.c
> @@ -52,7 +52,6 @@ static void *vcpu_worker(void *data)
>   	struct timespec start;
>   	struct timespec ts_diff;
>   
> -	vcpu_args_set(vm, vcpu_id, 1, vcpu_id);
>   	run = vcpu_state(vm, vcpu_id);
>   
>   	clock_gettime(CLOCK_MONOTONIC, &start);
> diff --git a/tools/testing/selftests/kvm/dirty_log_perf_test.c b/tools/testing/selftests/kvm/dirty_log_perf_test.c
> index 80cbd3a748c0..ef45a133560f 100644
> --- a/tools/testing/selftests/kvm/dirty_log_perf_test.c
> +++ b/tools/testing/selftests/kvm/dirty_log_perf_test.c
> @@ -44,7 +44,6 @@ static void *vcpu_worker(void *data)
>   	struct perf_test_vcpu_args *vcpu_args = (struct perf_test_vcpu_args *)data;
>   	int vcpu_id = vcpu_args->vcpu_id;
>   
> -	vcpu_args_set(vm, vcpu_id, 1, vcpu_id);
>   	run = vcpu_state(vm, vcpu_id);
>   
>   	while (!READ_ONCE(host_quit)) {
> diff --git a/tools/testing/selftests/kvm/lib/perf_test_util.c b/tools/testing/selftests/kvm/lib/perf_test_util.c
> index b488f4aefea8..f6aa81af3e6f 100644
> --- a/tools/testing/selftests/kvm/lib/perf_test_util.c
> +++ b/tools/testing/selftests/kvm/lib/perf_test_util.c
> @@ -140,6 +140,8 @@ void perf_test_setup_vcpus(struct kvm_vm *vm, int vcpus,
>   			vcpu_gpa = guest_test_phys_mem;
>   		}
>   
> +		vcpu_args_set(vm, vcpu_id, 1, vcpu_id);
> +
>   		pr_debug("Added VCPU %d with test mem gpa [%lx, %lx)\n",
>   			 vcpu_id, vcpu_gpa, vcpu_gpa +
>   			 (vcpu_args->pages * perf_test_args.guest_page_size));
> diff --git a/tools/testing/selftests/kvm/memslot_modification_stress_test.c b/tools/testing/selftests/kvm/memslot_modification_stress_test.c
> index 98351ba0933c..b6f7cc298e4d 100644
> --- a/tools/testing/selftests/kvm/memslot_modification_stress_test.c
> +++ b/tools/testing/selftests/kvm/memslot_modification_stress_test.c
> @@ -45,7 +45,6 @@ static void *vcpu_worker(void *data)
>   	struct kvm_vm *vm = perf_test_args.vm;
>   	struct kvm_run *run;
>   
> -	vcpu_args_set(vm, vcpu_id, 1, vcpu_id);
>   	run = vcpu_state(vm, vcpu_id);
>   
>   	/* Let the guest access its memory until a stop signal is received */
>