KVM: selftests: Add vm->memslots[] and enum kvm_mem_region_type

The vm_create() helpers are hardcoded to place most page types (code,
page-tables, stacks, etc) in the same memslot #0, and always backed with
anonymous 4K.  There are a couple of issues with that.  First, tests
willing to differ a bit, like placing page-tables in a different backing
source type must replicate much of what's already done by the vm_create()
functions.  Second, the hardcoded assumption of memslot #0 holding most
things is spread everywhere; this makes it very hard to change.

Fix the above issues by having selftests specify how they want memory to be
laid out. Start by changing ____vm_create() to not create memslot #0; a
test (to come) will specify all memslots used by the VM.  Then, add the
vm->memslots[] array to specify the right memslot for different memory
allocators, e.g.,: lib/elf should use the vm->[MEM_REGION_CODE] memslot.
This will be used as a way to specify the page-tables memslots (to be
backed by huge pages for example).

There is no functional change intended. The current commit lays out memory
exactly as before. A future commit will change the allocators to get the
region they should be using, e.g.,: like the page table allocators using
the pt memslot.

Cc: Sean Christopherson <[email protected]>
Cc: Andrew Jones <[email protected]>
Signed-off-by: Ricardo Koller <[email protected]>
Reviewed-by: Andrew Jones <[email protected]>
Reviewed-by: Sean Christopherson <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

1 files changed, 10 insertions, 8 deletions

diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 6affce47e899..f3dfa4e9ee0f 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -185,13 +185,10 @@ 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?");
 
-struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages)
+struct kvm_vm *____vm_create(enum vm_guest_mode mode)
 {
 	struct kvm_vm *vm;
 
-	pr_debug("%s: mode='%s' pages='%ld'\n", __func__,
-		 vm_guest_mode_string(mode), nr_pages);
-
 	vm = calloc(1, sizeof(*vm));
 	TEST_ASSERT(vm != NULL, "Insufficient Memory");
 
@@ -287,9 +284,6 @@ struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages)
 
 	/* Allocate and setup memory for guest. */
 	vm->vpages_mapped = sparsebit_alloc();
-	if (nr_pages != 0)
-		vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
-					    0, 0, nr_pages, 0);
 
 	return vm;
 }
@@ -335,8 +329,16 @@ struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus,
 	uint64_t nr_pages = vm_nr_pages_required(mode, nr_runnable_vcpus,
 						 nr_extra_pages);
 	struct kvm_vm *vm;
+	int i;
+
+	pr_debug("%s: mode='%s' pages='%ld'\n", __func__,
+		 vm_guest_mode_string(mode), nr_pages);
+
+	vm = ____vm_create(mode);
 
-	vm = ____vm_create(mode, nr_pages);
+	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, 0, 0, nr_pages, 0);
+	for (i = 0; i < NR_MEM_REGIONS; i++)
+		vm->memslots[i] = 0;
 
 	kvm_vm_elf_load(vm, program_invocation_name);