KVM: selftests: Make sure vm->vpages_mapped is always up-to-date

Call paths leading to __virt_pg_map() are currently:
(a) virt_pg_map() -> virt_arch_pg_map() -> __virt_pg_map()
(b) virt_map_level() -> __virt_pg_map()

For (a), calls to virt_pg_map() from kvm_util.c make sure they update
vm->vpages_mapped, but other callers do not. Move the sparsebit_set()
call into virt_pg_map() to make sure all callers are captured.

For (b), call sparsebit_set_num() from virt_map_level().

It's tempting to have a single the call inside __virt_pg_map(), however:
- The call path in (a) is not x86-specific, while (b) is. Moving the
  call into __virt_pg_map() would require doing something similar for
  other archs implementing virt_pg_map().

- Future changes will reusue __virt_pg_map() for nested PTEs, which should
  not update vm->vpages_mapped, i.e. a triple underscore version that does
  not update vm->vpages_mapped would need to be provided.

Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Link: https://patch.msgid.link/20251021074736.1324328-12-yosry.ahmed@linux.dev
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/tools/testing/selftests/kvm/lib/x86/processor.c b/tools/testing/selftests/kvm/lib/x86/processor.c
index 40bd69b265ef..36104d27f3d9 100644
--- a/tools/testing/selftests/kvm/lib/x86/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86/processor.c
@@ -286,6 +286,8 @@ void virt_map_level(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,
 
 	for (i = 0; i < nr_pages; i++) {
 		__virt_pg_map(vm, vaddr, paddr, level);
+		sparsebit_set_num(vm->vpages_mapped, vaddr >> vm->page_shift,
+				  nr_bytes / PAGE_SIZE);
 
 		vaddr += pg_size;
 		paddr += pg_size;