Re: [PATCH v2 5/6] KVM: selftests: Test for KVM_CAP_INJECT_EXT_IABT

[Oliver Upton <oliver.upton@linux.dev>]

On Wed, Jun 04, 2025 at 05:09:00AM +0000, Jiaqi Yan wrote:
> Test userspace can use KVM_SET_VCPU_EVENTS to inject an external
> instruction abort into guest. The test injects instruction abort at an
> arbitrary time without real SEA happening in the guest VCPU, so only
> certain ESR_EL1 bits are expected and asserted.
> 
> Signed-off-by: Jiaqi Yan <jiaqiyan@google.com>

I reworked mmio_abort to be a general external abort test, can you add
your test cases there in the next spin (arm64/external_aborts.c)?

Thanks,
Oliver

> ---
>  tools/arch/arm64/include/uapi/asm/kvm.h       |  3 +-
>  tools/testing/selftests/kvm/Makefile.kvm      |  1 +
>  .../testing/selftests/kvm/arm64/inject_iabt.c | 98 +++++++++++++++++++
>  3 files changed, 101 insertions(+), 1 deletion(-)
>  create mode 100644 tools/testing/selftests/kvm/arm64/inject_iabt.c
> 
> diff --git a/tools/arch/arm64/include/uapi/asm/kvm.h b/tools/arch/arm64/include/uapi/asm/kvm.h
> index af9d9acaf9975..d3a4530846311 100644
> --- a/tools/arch/arm64/include/uapi/asm/kvm.h
> +++ b/tools/arch/arm64/include/uapi/asm/kvm.h
> @@ -184,8 +184,9 @@ struct kvm_vcpu_events {
>  		__u8 serror_pending;
>  		__u8 serror_has_esr;
>  		__u8 ext_dabt_pending;
> +		__u8 ext_iabt_pending;
>  		/* Align it to 8 bytes */
> -		__u8 pad[5];
> +		__u8 pad[4];
>  		__u64 serror_esr;
>  	} exception;
>  	__u32 reserved[12];
> diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
> index 9eecce6b8274f..e6b504ded9c1c 100644
> --- a/tools/testing/selftests/kvm/Makefile.kvm
> +++ b/tools/testing/selftests/kvm/Makefile.kvm
> @@ -149,6 +149,7 @@ TEST_GEN_PROGS_arm64 += arm64/arch_timer_edge_cases
>  TEST_GEN_PROGS_arm64 += arm64/debug-exceptions
>  TEST_GEN_PROGS_arm64 += arm64/host_sve
>  TEST_GEN_PROGS_arm64 += arm64/hypercalls
> +TEST_GEN_PROGS_arm64 += arm64/inject_iabt
>  TEST_GEN_PROGS_arm64 += arm64/mmio_abort
>  TEST_GEN_PROGS_arm64 += arm64/page_fault_test
>  TEST_GEN_PROGS_arm64 += arm64/psci_test
> diff --git a/tools/testing/selftests/kvm/arm64/inject_iabt.c b/tools/testing/selftests/kvm/arm64/inject_iabt.c
> new file mode 100644
> index 0000000000000..0c7999e5ba5b3
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/arm64/inject_iabt.c
> @@ -0,0 +1,98 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * inject_iabt.c - Tests for injecting instruction aborts into guest.
> + */
> +
> +#include "processor.h"
> +#include "test_util.h"
> +
> +static void expect_iabt_handler(struct ex_regs *regs)
> +{
> +	u64 esr = read_sysreg(esr_el1);
> +
> +	GUEST_PRINTF("Handling Guest SEA\n");
> +	GUEST_PRINTF("  ESR_EL1=%#lx\n", esr);
> +
> +	GUEST_ASSERT_EQ(ESR_ELx_EC(esr), ESR_ELx_EC_IABT_CUR);
> +	GUEST_ASSERT_EQ(esr & ESR_ELx_FSC_TYPE, ESR_ELx_FSC_EXTABT);
> +
> +	GUEST_DONE();
> +}
> +
> +static void guest_code(void)
> +{
> +	GUEST_FAIL("Guest should only run SEA handler");
> +}
> +
> +static void vcpu_run_expect_done(struct kvm_vcpu *vcpu)
> +{
> +	struct ucall uc;
> +	bool guest_done = false;
> +
> +	do {
> +		vcpu_run(vcpu);
> +		switch (get_ucall(vcpu, &uc)) {
> +		case UCALL_ABORT:
> +			REPORT_GUEST_ASSERT(uc);
> +			break;
> +		case UCALL_PRINTF:
> +			ksft_print_msg("From guest: %s", uc.buffer);
> +			break;
> +		case UCALL_DONE:
> +			ksft_print_msg("Guest done gracefully!\n");
> +			guest_done = true;
> +			break;
> +		default:
> +			TEST_FAIL("Unexpected ucall: %lu", uc.cmd);
> +		}
> +	} while (!guest_done);
> +}
> +
> +static void vcpu_inject_ext_iabt(struct kvm_vcpu *vcpu)
> +{
> +	struct kvm_vcpu_events events = {};
> +
> +	events.exception.ext_iabt_pending = true;
> +	vcpu_events_set(vcpu, &events);
> +}
> +
> +static void vcpu_inject_invalid_abt(struct kvm_vcpu *vcpu)
> +{
> +	struct kvm_vcpu_events events = {};
> +	int r;
> +
> +	events.exception.ext_iabt_pending = true;
> +	events.exception.ext_dabt_pending = true;
> +
> +	ksft_print_msg("Injecting invalid external abort events\n");
> +	r = __vcpu_ioctl(vcpu, KVM_SET_VCPU_EVENTS, &events);
> +	TEST_ASSERT(r && errno == EINVAL,
> +		    KVM_IOCTL_ERROR(KVM_SET_VCPU_EVENTS, r));
> +}
> +
> +static void test_inject_iabt(void)
> +{
> +	struct kvm_vcpu *vcpu;
> +	struct kvm_vm *vm;
> +
> +	vm = vm_create_with_one_vcpu(&vcpu, guest_code);
> +
> +	vm_init_descriptor_tables(vm);
> +	vcpu_init_descriptor_tables(vcpu);
> +
> +	vm_install_sync_handler(vm, VECTOR_SYNC_CURRENT,
> +				ESR_ELx_EC_IABT_CUR, expect_iabt_handler);
> +
> +	vcpu_inject_invalid_abt(vcpu);
> +
> +	vcpu_inject_ext_iabt(vcpu);
> +	vcpu_run_expect_done(vcpu);
> +
> +	kvm_vm_free(vm);
> +}
> +
> +int main(void)
> +{
> +	test_inject_iabt();
> +	return 0;
> +}
> -- 
> 2.49.0.1266.g31b7d2e469-goog
>