Commit 2103a8ba authored by Jim Mattson's avatar Jim Mattson Committed by Sean Christopherson
Browse files

KVM: selftests: Use a loop to walk guest page tables 



Walk the guest page tables via a loop when searching for a PTE,
instead of using unique variables for each level of the page tables.

This simplifies the code and makes it easier to support 5-level paging
in the future.

Signed-off-by: default avatarJim Mattson <jmattson@google.com>
Reviewed-by: default avatarYosry Ahmed <yosry.ahmed@linux.dev>
Link: https://patch.msgid.link/20251028225827.2269128-3-jmattson@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent ae5b498b

tools/testing/selftests/kvm/lib/x86/processor.c

+10 −13
Original line number Diff line number Diff line
@@ -307,7 +307,8 @@ static bool vm_is_target_pte(uint64_t *pte, int *level, int current_level) 
uint64_t *__vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr,

				    int *level)

{

	uint64_t *pml4e, *pdpe, *pde;

	uint64_t *pte = &vm->pgd;

	int current_level;



	TEST_ASSERT(!vm->arch.is_pt_protected,

		    "Walking page tables of protected guests is impossible");
@@ -328,19 +329,15 @@ uint64_t *__vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr, 
	TEST_ASSERT(vaddr == (((int64_t)vaddr << 16) >> 16),

		"Canonical check failed.  The virtual address is invalid.");



	pml4e = virt_get_pte(vm, &vm->pgd, vaddr, PG_LEVEL_512G);

	if (vm_is_target_pte(pml4e, level, PG_LEVEL_512G))

		return pml4e;



	pdpe = virt_get_pte(vm, pml4e, vaddr, PG_LEVEL_1G);

	if (vm_is_target_pte(pdpe, level, PG_LEVEL_1G))

		return pdpe;



	pde = virt_get_pte(vm, pdpe, vaddr, PG_LEVEL_2M);

	if (vm_is_target_pte(pde, level, PG_LEVEL_2M))

		return pde;

	for (current_level = vm->pgtable_levels;

	     current_level > PG_LEVEL_4K;

	     current_level--) {

		pte = virt_get_pte(vm, pte, vaddr, current_level);

		if (vm_is_target_pte(pte, level, current_level))

			return pte;

	}



	return virt_get_pte(vm, pde, vaddr, PG_LEVEL_4K);

	return virt_get_pte(vm, pte, vaddr, PG_LEVEL_4K);

}



uint64_t *vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr)