An interesting feature of the Arm architecture is that the stage-1 MMU supports two distinct VA regions, controlled by TTBR{0,1}_EL1. As KVM selftests on arm64 only uses TTBR0_EL1, the VA space is constrained to [0, 2^(va_bits-1)). This is different from other architectures that allow for addressing low and high regions of the VA space from a single page table.
KVM selftests' VA space allocator presumes the valid address range is split between low and high memory based the MSB, which of course is a poor match for arm64's TTBR0 region.
Allow architectures to override the default VA space layout. Make use of the override to align vpages_valid with the behavior of TTBR0 on arm64.
Signed-off-by: Oliver Upton oliver.upton@linux.dev --- .../testing/selftests/kvm/include/kvm_util_base.h | 1 + .../testing/selftests/kvm/lib/aarch64/processor.c | 10 ++++++++++ tools/testing/selftests/kvm/lib/kvm_util.c | 15 ++++++++++----- 3 files changed, 21 insertions(+), 5 deletions(-)
diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h index 6cd86da698b3..fbc2a79369b8 100644 --- a/tools/testing/selftests/kvm/include/kvm_util_base.h +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h @@ -420,6 +420,7 @@ void vm_mem_region_set_flags(struct kvm_vm *vm, uint32_t slot, uint32_t flags); void vm_mem_region_move(struct kvm_vm *vm, uint32_t slot, uint64_t new_gpa); void vm_mem_region_delete(struct kvm_vm *vm, uint32_t slot); struct kvm_vcpu *__vm_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id); +void vm_populate_vaddr_bitmap(struct kvm_vm *vm); vm_vaddr_t vm_vaddr_unused_gap(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min); vm_vaddr_t vm_vaddr_alloc(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min); vm_vaddr_t __vm_vaddr_alloc(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min, diff --git a/tools/testing/selftests/kvm/lib/aarch64/processor.c b/tools/testing/selftests/kvm/lib/aarch64/processor.c index 316de70db91d..5972a23b2765 100644 --- a/tools/testing/selftests/kvm/lib/aarch64/processor.c +++ b/tools/testing/selftests/kvm/lib/aarch64/processor.c @@ -541,3 +541,13 @@ void kvm_selftest_arch_init(void) */ guest_modes_append_default(); } + +void vm_vaddr_populate_bitmap(struct kvm_vm *vm) +{ + /* + * arm64 selftests use only TTBR0_EL1, meaning that the valid VA space + * is [0, 2^(64 - TCR_EL1.T0SZ)). + */ + sparsebit_set_num(vm->vpages_valid, 0, + (1ULL << vm->va_bits) >> vm->page_shift); +} diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index e9607eb089be..c88c3ace16d2 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -186,6 +186,15 @@ 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?");
+__weak void vm_vaddr_populate_bitmap(struct kvm_vm *vm) +{ + sparsebit_set_num(vm->vpages_valid, + 0, (1ULL << (vm->va_bits - 1)) >> vm->page_shift); + sparsebit_set_num(vm->vpages_valid, + (~((1ULL << (vm->va_bits - 1)) - 1)) >> vm->page_shift, + (1ULL << (vm->va_bits - 1)) >> vm->page_shift); +} + struct kvm_vm *____vm_create(enum vm_guest_mode mode) { struct kvm_vm *vm; @@ -274,11 +283,7 @@ struct kvm_vm *____vm_create(enum vm_guest_mode mode)
/* Limit to VA-bit canonical virtual addresses. */ vm->vpages_valid = sparsebit_alloc(); - sparsebit_set_num(vm->vpages_valid, - 0, (1ULL << (vm->va_bits - 1)) >> vm->page_shift); - sparsebit_set_num(vm->vpages_valid, - (~((1ULL << (vm->va_bits - 1)) - 1)) >> vm->page_shift, - (1ULL << (vm->va_bits - 1)) >> vm->page_shift); + vm_vaddr_populate_bitmap(vm);
/* Limit physical addresses to PA-bits. */ vm->max_gfn = vm_compute_max_gfn(vm);