Re: [RFC PATCH 1/2] KVM: selftests: Add a macro to get string of vm_mem_backing_src_type

wangyanan (Y)
2021-02-09T11:25:06Z

On 2021/2/9 2:13, Ben Gardon wrote:
> On Mon, Feb 8, 2021 at 1:08 AM Yanan Wang <wangyanan55@huawei.com> wrote:
>> Add a macro to get string of the backing source memory type, so that
>> application can add choices for source types in the help() function,
>> and users can specify which type to use for testing.
> Coincidentally, I sent out a change last week to do the same thing:
> "KVM: selftests: Add backing src parameter to dirty_log_perf_test"
> (https://lkml.org/lkml/2021/2/2/1430)
> Whichever way this ends up being implemented, I'm happy to see others
> interested in testing different backing source types too.

Thanks Ben! I have a little question here.

Can we just present three IDs (0/1/2) but not strings for users to
choose which backing_src_type to use like the way of guest modes,

which I think can make cmdlines more consise and easier to print. And is
it better to make a universal API to get backing_src_strings

like Sean have suggested, so that the API can be used elsewhere ?

>> Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
>> ---
>> tools/testing/selftests/kvm/include/kvm_util.h | 3 +++
>> tools/testing/selftests/kvm/lib/kvm_util.c | 8 ++++++++
>> 2 files changed, 11 insertions(+)
>>
>> diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
>> index 5cbb861525ed..f5fc29dc9ee6 100644
>> --- a/tools/testing/selftests/kvm/include/kvm_util.h
>> +++ b/tools/testing/selftests/kvm/include/kvm_util.h
>> @@ -69,7 +69,9 @@ enum vm_guest_mode {
>> #define PTES_PER_MIN_PAGE ptes_per_page(MIN_PAGE_SIZE)
>>
>> #define vm_guest_mode_string(m) vm_guest_mode_string[m]
>> +#define vm_mem_backing_src_type_string(s) vm_mem_backing_src_type_string[s]
>> extern const char * const vm_guest_mode_string[];
>> +extern const char * const vm_mem_backing_src_type_string[];
>>
>> struct vm_guest_mode_params {
>> unsigned int pa_bits;
>> @@ -83,6 +85,7 @@ enum vm_mem_backing_src_type {
>> VM_MEM_SRC_ANONYMOUS,
>> VM_MEM_SRC_ANONYMOUS_THP,
>> VM_MEM_SRC_ANONYMOUS_HUGETLB,
>> + NUM_VM_BACKING_SRC_TYPES,
>> };
>>
>> int kvm_check_cap(long cap);
>> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
>> index fa5a90e6c6f0..a9b651c7f866 100644
>> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
>> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
>> @@ -165,6 +165,14 @@ const struct vm_guest_mode_params vm_guest_mode_params[] = {
>> _Static_assert(sizeof(vm_guest_mode_params)/sizeof(struct vm_guest_mode_params) == NUM_VM_MODES,
>> "Missing new mode params?");
>>
>> +const char * const vm_mem_backing_src_type_string[] = {
>> + "VM_MEM_SRC_ANONYMOUS ",
>> + "VM_MEM_SRC_ANONYMOUS_THP ",
>> + "VM_MEM_SRC_ANONYMOUS_HUGETLB",
>> +};
>> +_Static_assert(sizeof(vm_mem_backing_src_type_string)/sizeof(char *) == NUM_VM_BACKING_SRC_TYPES,
>> + "Missing new source type strings?");
>> +
>> /*
>> * VM Create
>> *
>> --
>> 2.23.0
>>
> .