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

[wangyanan (Y)]

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 <wangyana...@huawei.com>
And here too, will include Suggested-by: Sean Christopherson 
<sea...@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 },