[PATCH v1 2/2] KVM: selftests: arm64: Fix pte encode/decode for PA bits > 48

Ryan Roberts
2023-02-28T17:08:48Z

The high bits [51:48] of a physical address should appear at [15:12] in
a 64K pte, not at [51:48] as was previously being programmed. Fix this
with new helper functions that do the conversion correctly. This also
sets us up nicely for adding LPA2 encodings in future.

Fixes: 7a6629ef746d ("kvm: selftests: add virt mem support for aarch64")

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
---
.../selftests/kvm/lib/aarch64/processor.c | 32 ++++++++++++++-----
1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/kvm/lib/aarch64/processor.c b/tools/testing/selftests/kvm/lib/aarch64/processor.c
index 5972a23b2765..13f28d96521c 100644
--- a/tools/testing/selftests/kvm/lib/aarch64/processor.c
+++ b/tools/testing/selftests/kvm/lib/aarch64/processor.c
@@ -58,10 +58,27 @@ static uint64_t pte_index(struct kvm_vm *vm, vm_vaddr_t gva)
return (gva >> vm->page_shift) & mask;
}

-static uint64_t pte_addr(struct kvm_vm *vm, uint64_t entry)
+static uint64_t addr_pte(struct kvm_vm *vm, uint64_t pa, uint64_t attrs)
{
- uint64_t mask = ((1UL << (vm->va_bits - vm->page_shift)) - 1) << vm->page_shift;
- return entry & mask;
+ uint64_t pte;
+
+ pte = pa & GENMASK(47, vm->page_shift);
+ if (vm->page_shift == 16)
+ pte |= (pa & GENMASK(51, 48)) >> (48 - 12);
+ pte |= attrs;
+
+ return pte;
+}
+
+static uint64_t pte_addr(struct kvm_vm *vm, uint64_t pte)
+{
+ uint64_t pa;
+
+ pa = pte & GENMASK(47, vm->page_shift);
+ if (vm->page_shift == 16)
+ pa |= (pte & GENMASK(15, 12)) << (48 - 12);
+
+ return pa;
}

static uint64_t ptrs_per_pgd(struct kvm_vm *vm)
@@ -110,18 +127,18 @@ static void _virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,

ptep = addr_gpa2hva(vm, vm->pgd) + pgd_index(vm, vaddr) * 8;
if (!*ptep)
- *ptep = vm_alloc_page_table(vm) | 3;
+ *ptep = addr_pte(vm, vm_alloc_page_table(vm), 3);

switch (vm->pgtable_levels) {
case 4:
ptep = addr_gpa2hva(vm, pte_addr(vm, *ptep)) + pud_index(vm, vaddr) * 8;
if (!*ptep)
- *ptep = vm_alloc_page_table(vm) | 3;
+ *ptep = addr_pte(vm, vm_alloc_page_table(vm), 3);
/* fall through */
case 3:
ptep = addr_gpa2hva(vm, pte_addr(vm, *ptep)) + pmd_index(vm, vaddr) * 8;
if (!*ptep)
- *ptep = vm_alloc_page_table(vm) | 3;
+ *ptep = addr_pte(vm, vm_alloc_page_table(vm), 3);
/* fall through */
case 2:
ptep = addr_gpa2hva(vm, pte_addr(vm, *ptep)) + pte_index(vm, vaddr) * 8;
@@ -130,8 +147,7 @@ static void _virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,
TEST_FAIL("Page table levels must be 2, 3, or 4");
}

- *ptep = paddr | 3;
- *ptep |= (attr_idx << 2) | (1 << 10) /* Access Flag */;
+ *ptep = addr_pte(vm, paddr, (attr_idx << 2) | (1 << 10) | 3); /* AF */
}

void virt_arch_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr)
--
2.25.1