diff options
Diffstat (limited to 'tools/testing/selftests/kvm/arm64/at.c')
| -rw-r--r-- | tools/testing/selftests/kvm/arm64/at.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/arm64/at.c b/tools/testing/selftests/kvm/arm64/at.c new file mode 100644 index 000000000000..c8ee6f520734 --- /dev/null +++ b/tools/testing/selftests/kvm/arm64/at.c @@ -0,0 +1,166 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * at - Test for KVM's AT emulation in the EL2&0 and EL1&0 translation regimes. + */ +#include "kvm_util.h" +#include "processor.h" +#include "test_util.h" +#include "ucall.h" + +#include <asm/sysreg.h> + +#define TEST_ADDR 0x80000000 + +enum { + CLEAR_ACCESS_FLAG, + TEST_ACCESS_FLAG, +}; + +static u64 *ptep_hva; + +#define copy_el2_to_el1(reg) \ + write_sysreg_s(read_sysreg_s(SYS_##reg##_EL1), SYS_##reg##_EL12) + +/* Yes, this is an ugly hack */ +#define __at(op, addr) write_sysreg_s(addr, op) + +#define test_at_insn(op, expect_fault) \ +do { \ + u64 par, fsc; \ + bool fault; \ + \ + GUEST_SYNC(CLEAR_ACCESS_FLAG); \ + \ + __at(OP_AT_##op, TEST_ADDR); \ + isb(); \ + par = read_sysreg(par_el1); \ + \ + fault = par & SYS_PAR_EL1_F; \ + fsc = FIELD_GET(SYS_PAR_EL1_FST, par); \ + \ + __GUEST_ASSERT((expect_fault) == fault, \ + "AT "#op": %sexpected fault (par: %lx)1", \ + (expect_fault) ? "" : "un", par); \ + if ((expect_fault)) { \ + __GUEST_ASSERT(fsc == ESR_ELx_FSC_ACCESS_L(3), \ + "AT "#op": expected access flag fault (par: %lx)", \ + par); \ + } else { \ + GUEST_ASSERT_EQ(FIELD_GET(SYS_PAR_EL1_ATTR, par), MAIR_ATTR_NORMAL); \ + GUEST_ASSERT_EQ(FIELD_GET(SYS_PAR_EL1_SH, par), PTE_SHARED >> 8); \ + GUEST_ASSERT_EQ(par & SYS_PAR_EL1_PA, TEST_ADDR); \ + GUEST_SYNC(TEST_ACCESS_FLAG); \ + } \ +} while (0) + +static void test_at(bool expect_fault) +{ + test_at_insn(S1E2R, expect_fault); + test_at_insn(S1E2W, expect_fault); + + /* Reuse the stage-1 MMU context from EL2 at EL1 */ + copy_el2_to_el1(SCTLR); + copy_el2_to_el1(MAIR); + copy_el2_to_el1(TCR); + copy_el2_to_el1(TTBR0); + copy_el2_to_el1(TTBR1); + + /* Disable stage-2 translation and enter a non-host context */ + write_sysreg(0, vtcr_el2); + write_sysreg(0, vttbr_el2); + sysreg_clear_set(hcr_el2, HCR_EL2_TGE | HCR_EL2_VM, 0); + isb(); + + test_at_insn(S1E1R, expect_fault); + test_at_insn(S1E1W, expect_fault); +} + +static void guest_code(void) +{ + sysreg_clear_set(tcr_el1, TCR_HA, 0); + isb(); + + test_at(true); + + if (!SYS_FIELD_GET(ID_AA64MMFR1_EL1, HAFDBS, read_sysreg(id_aa64mmfr1_el1))) + GUEST_DONE(); + + /* + * KVM's software PTW makes the implementation choice that the AT + * instruction sets the access flag. + */ + sysreg_clear_set(tcr_el1, 0, TCR_HA); + isb(); + test_at(false); + + GUEST_DONE(); +} + +static void handle_sync(struct kvm_vcpu *vcpu, struct ucall *uc) +{ + switch (uc->args[1]) { + case CLEAR_ACCESS_FLAG: + /* + * Delete + reinstall the memslot to invalidate stage-2 + * mappings of the stage-1 page tables, forcing KVM to + * use the 'slow' AT emulation path. + * + * This and clearing the access flag from host userspace + * ensures that the access flag cannot be set speculatively + * and is reliably cleared at the time of the AT instruction. + */ + clear_bit(__ffs(PTE_AF), ptep_hva); + vm_mem_region_reload(vcpu->vm, vcpu->vm->memslots[MEM_REGION_PT]); + break; + case TEST_ACCESS_FLAG: + TEST_ASSERT(test_bit(__ffs(PTE_AF), ptep_hva), + "Expected access flag to be set (desc: %lu)", *ptep_hva); + break; + default: + TEST_FAIL("Unexpected SYNC arg: %lu", uc->args[1]); + } +} + +static void run_test(struct kvm_vcpu *vcpu) +{ + struct ucall uc; + + while (true) { + vcpu_run(vcpu); + switch (get_ucall(vcpu, &uc)) { + case UCALL_DONE: + return; + case UCALL_SYNC: + handle_sync(vcpu, &uc); + continue; + case UCALL_ABORT: + REPORT_GUEST_ASSERT(uc); + return; + default: + TEST_FAIL("Unexpected ucall: %lu", uc.cmd); + } + } +} + +int main(void) +{ + struct kvm_vcpu_init init; + struct kvm_vcpu *vcpu; + struct kvm_vm *vm; + + TEST_REQUIRE(kvm_check_cap(KVM_CAP_ARM_EL2)); + + vm = vm_create(1); + + kvm_get_default_vcpu_target(vm, &init); + init.features[0] |= BIT(KVM_ARM_VCPU_HAS_EL2); + vcpu = aarch64_vcpu_add(vm, 0, &init, guest_code); + kvm_arch_vm_finalize_vcpus(vm); + + virt_map(vm, TEST_ADDR, TEST_ADDR, 1); + ptep_hva = virt_get_pte_hva_at_level(vm, TEST_ADDR, 3); + run_test(vcpu); + + kvm_vm_free(vm); + return 0; +} |