On Tue, Oct 28, 2025 at 03:30:39PM -0700, Jim Mattson wrote:
Walk the guest page tables via a loop when creating new mappings, 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: Jim Mattson jmattson@google.com
Reviewed-by: Yosry Ahmed yosry.ahmed@linux.dev
.../testing/selftests/kvm/lib/x86/processor.c | 25 ++++++++----------- 1 file changed, 11 insertions(+), 14 deletions(-)
diff --git a/tools/testing/selftests/kvm/lib/x86/processor.c b/tools/testing/selftests/kvm/lib/x86/processor.c index b418502c5ecc..738f2a44083f 100644 --- a/tools/testing/selftests/kvm/lib/x86/processor.c +++ b/tools/testing/selftests/kvm/lib/x86/processor.c @@ -218,8 +218,8 @@ static uint64_t *virt_create_upper_pte(struct kvm_vm *vm, void __virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr, int level) { const uint64_t pg_size = PG_LEVEL_SIZE(level);
- uint64_t *pml4e, *pdpe, *pde;
- uint64_t *pte;
- uint64_t *pte = &vm->pgd;
- int current_level;
TEST_ASSERT(vm->mode == VM_MODE_PXXV48_4K, "Unknown or unsupported guest mode, mode: 0x%x", vm->mode); @@ -243,20 +243,17 @@ void __virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr, int level) * Allocate upper level page tables, if not already present. Return * early if a hugepage was created. */
- pml4e = virt_create_upper_pte(vm, &vm->pgd, vaddr, paddr, PG_LEVEL_512G, level);
- if (*pml4e & PTE_LARGE_MASK)
return;- pdpe = virt_create_upper_pte(vm, pml4e, vaddr, paddr, PG_LEVEL_1G, level);
- if (*pdpe & PTE_LARGE_MASK)
return;- pde = virt_create_upper_pte(vm, pdpe, vaddr, paddr, PG_LEVEL_2M, level);
- if (*pde & PTE_LARGE_MASK)
return;
- for (current_level = vm->pgtable_levels;
current_level > PG_LEVEL_4K;current_level--) {pte = virt_create_upper_pte(vm, pte, vaddr, paddr,current_level, level);if (*pte & PTE_LARGE_MASK)return;- }
/* Fill in page table entry. */
- pte = virt_get_pte(vm, pde, vaddr, PG_LEVEL_4K);
- pte = virt_get_pte(vm, pte, vaddr, PG_LEVEL_4K); TEST_ASSERT(!(*pte & PTE_PRESENT_MASK), "PTE already present for 4k page at vaddr: 0x%lx", vaddr); *pte = PTE_PRESENT_MASK | PTE_WRITABLE_MASK | (paddr & PHYSICAL_PAGE_MASK);
-- 2.51.1.851.g4ebd6896fd-goog