Re: [RFC PATCH v2 3/7] KVM: selftests: Make a generic helper to get vm guest mode strings

["wangyanan (Y)" <wangyanan55@huawei.com>]

On 2021/2/25 13:59, Yanan Wang wrote:
> For generality and conciseness, make an API which can be used in all
> kvm libs and selftests to get vm guest mode strings. And the index i
> is checked in the API in case of possiable faults.
>
> Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
And here too, will include Suggested-by: Sean Christopherson 
<seanjc@google.com>.
> ---
>   .../testing/selftests/kvm/include/kvm_util.h  |  4 +--
>   tools/testing/selftests/kvm/lib/kvm_util.c    | 29 ++++++++++++-------
>   2 files changed, 19 insertions(+), 14 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
> index 2d7eb6989e83..f52a7492f47f 100644
> --- a/tools/testing/selftests/kvm/include/kvm_util.h
> +++ b/tools/testing/selftests/kvm/include/kvm_util.h
> @@ -68,9 +68,6 @@ enum vm_guest_mode {
>   #define MIN_PAGE_SIZE		(1U << MIN_PAGE_SHIFT)
>   #define PTES_PER_MIN_PAGE	ptes_per_page(MIN_PAGE_SIZE)
>   
> -#define vm_guest_mode_string(m) vm_guest_mode_string[m]
> -extern const char * const vm_guest_mode_string[];
> -
>   struct vm_guest_mode_params {
>   	unsigned int pa_bits;
>   	unsigned int va_bits;
> @@ -84,6 +81,7 @@ int vm_enable_cap(struct kvm_vm *vm, struct kvm_enable_cap *cap);
>   int vcpu_enable_cap(struct kvm_vm *vm, uint32_t vcpu_id,
>   		    struct kvm_enable_cap *cap);
>   void vm_enable_dirty_ring(struct kvm_vm *vm, uint32_t ring_size);
> +const char *vm_guest_mode_string(uint32_t i);
>   
>   struct kvm_vm *vm_create(enum vm_guest_mode mode, uint64_t phy_pages, int perm);
>   void kvm_vm_free(struct kvm_vm *vmp);
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index d787cb802b4a..cc22c4ab7d67 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -141,17 +141,24 @@ static void vm_open(struct kvm_vm *vm, int perm)
>   		"rc: %i errno: %i", vm->fd, errno);
>   }
>   
> -const char * const vm_guest_mode_string[] = {
> -	"PA-bits:52,  VA-bits:48,  4K pages",
> -	"PA-bits:52,  VA-bits:48, 64K pages",
> -	"PA-bits:48,  VA-bits:48,  4K pages",
> -	"PA-bits:48,  VA-bits:48, 64K pages",
> -	"PA-bits:40,  VA-bits:48,  4K pages",
> -	"PA-bits:40,  VA-bits:48, 64K pages",
> -	"PA-bits:ANY, VA-bits:48,  4K pages",
> -};
> -_Static_assert(sizeof(vm_guest_mode_string)/sizeof(char *) == NUM_VM_MODES,
> -	       "Missing new mode strings?");
> +const char *vm_guest_mode_string(uint32_t i)
> +{
> +	static const char * const strings[] = {
> +		[VM_MODE_P52V48_4K]	= "PA-bits:52,  VA-bits:48,  4K pages",
> +		[VM_MODE_P52V48_64K]	= "PA-bits:52,  VA-bits:48, 64K pages",
> +		[VM_MODE_P48V48_4K]	= "PA-bits:48,  VA-bits:48,  4K pages",
> +		[VM_MODE_P48V48_64K]	= "PA-bits:48,  VA-bits:48, 64K pages",
> +		[VM_MODE_P40V48_4K]	= "PA-bits:40,  VA-bits:48,  4K pages",
> +		[VM_MODE_P40V48_64K]	= "PA-bits:40,  VA-bits:48, 64K pages",
> +		[VM_MODE_PXXV48_4K]	= "PA-bits:ANY, VA-bits:48,  4K pages",
> +	};
> +	_Static_assert(sizeof(strings)/sizeof(char *) == NUM_VM_MODES,
> +		       "Missing new mode strings?");
> +
> +	TEST_ASSERT(i < NUM_VM_MODES, "Guest mode ID %d too big", i);
> +
> +	return strings[i];
> +}
>   
>   const struct vm_guest_mode_params vm_guest_mode_params[] = {
>   	{ 52, 48,  0x1000, 12 },