KVM: selftests: Remove unused kvm_memcmp_hva_gva()

Remove sefltests' kvm_memcmp_hva_gva(), which has literally never had a
single user since it was introduced by commit 783e9e51 ("kvm:
selftests: add API testing infrastructure").

Link: https://lore.kernel.org/r/20240802200853.336512-1-seanjc@google.comSigned-off-by: Sean Christopherson <seanjc@google.com>

tools/testing/selftests/kvm/include/kvm_util.h

@@ -428,8 +428,6 @@ const char *vm_guest_mode_string(uint32_t i);
 void kvm_vm_free(struct kvm_vm *vmp);
 void kvm_vm_restart(struct kvm_vm *vmp);
 void kvm_vm_release(struct kvm_vm *vmp);
-int kvm_memcmp_hva_gva(void *hva, struct kvm_vm *vm, const vm_vaddr_t gva,
-		       size_t len);
 void kvm_vm_elf_load(struct kvm_vm *vm, const char *filename);
 int kvm_memfd_alloc(size_t size, bool hugepages);
 

tools/testing/selftests/kvm/lib/kvm_util.c

@@ -794,76 +794,6 @@ int kvm_memfd_alloc(size_t size, bool hugepages)
 	return fd;
 }
 
-/*
- * Memory Compare, host virtual to guest virtual
- *
- * Input Args:
- *   hva - Starting host virtual address
- *   vm - Virtual Machine
- *   gva - Starting guest virtual address
- *   len - number of bytes to compare
- *
- * Output Args: None
- *
- * Input/Output Args: None
- *
- * Return:
- *   Returns 0 if the bytes starting at hva for a length of len
- *   are equal the guest virtual bytes starting at gva.  Returns
- *   a value < 0, if bytes at hva are less than those at gva.
- *   Otherwise a value > 0 is returned.
- *
- * Compares the bytes starting at the host virtual address hva, for
- * a length of len, to the guest bytes starting at the guest virtual
- * address given by gva.
- */
-int kvm_memcmp_hva_gva(void *hva, struct kvm_vm *vm, vm_vaddr_t gva, size_t len)
-{
-	size_t amt;
-
-	/*
-	 * Compare a batch of bytes until either a match is found
-	 * or all the bytes have been compared.
-	 */
-	for (uintptr_t offset = 0; offset < len; offset += amt) {
-		uintptr_t ptr1 = (uintptr_t)hva + offset;
-
-		/*
-		 * Determine host address for guest virtual address
-		 * at offset.
-		 */
-		uintptr_t ptr2 = (uintptr_t)addr_gva2hva(vm, gva + offset);
-
-		/*
-		 * Determine amount to compare on this pass.
-		 * Don't allow the comparsion to cross a page boundary.
-		 */
-		amt = len - offset;
-		if ((ptr1 >> vm->page_shift) != ((ptr1 + amt) >> vm->page_shift))
-			amt = vm->page_size - (ptr1 % vm->page_size);
-		if ((ptr2 >> vm->page_shift) != ((ptr2 + amt) >> vm->page_shift))
-			amt = vm->page_size - (ptr2 % vm->page_size);
-
-		assert((ptr1 >> vm->page_shift) == ((ptr1 + amt - 1) >> vm->page_shift));
-		assert((ptr2 >> vm->page_shift) == ((ptr2 + amt - 1) >> vm->page_shift));
-
-		/*
-		 * Perform the comparison.  If there is a difference
-		 * return that result to the caller, otherwise need
-		 * to continue on looking for a mismatch.
-		 */
-		int ret = memcmp((void *)ptr1, (void *)ptr2, amt);
-		if (ret != 0)
-			return ret;
-	}
-
-	/*
-	 * No mismatch found.  Let the caller know the two memory
-	 * areas are equal.
-	 */
-	return 0;
-}
-
 static void vm_userspace_mem_region_gpa_insert(struct rb_root *gpa_tree,
 					       struct userspace_mem_region *region)
 {