* [PATCH] KVM: arm64: selftest: Add standalone test checking for KVM's own UUID @ 2025-07-21 15:51 Marc Zyngier 2025-07-22 9:18 ` Andrew Jones 2025-07-22 14:39 ` Sebastian Ott 0 siblings, 2 replies; 5+ messages in thread From: Marc Zyngier @ 2025-07-21 15:51 UTC (permalink / raw) To: kvmarm, kvm, linux-arm-kernel, linux-kernel Cc: Joey Gouly, Suzuki K Poulose, Oliver Upton, Zenghui Yu, Will Deacon, Mark Rutland, jackabt Tinkering with UUIDs is a perilious task, and the KVM UUID gets broken at times. In order to spot this early enough, add a selftest that will shout if the expected value isn't found. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20250721130558.50823-1-jackabt.amazon@gmail.com --- tools/testing/selftests/kvm/Makefile.kvm | 1 + tools/testing/selftests/kvm/arm64/kvm-uuid.c | 67 ++++++++++++++++++++ 2 files changed, 68 insertions(+) create mode 100644 tools/testing/selftests/kvm/arm64/kvm-uuid.c diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm index ce817a975e50a..e1eb1ba238a2a 100644 --- a/tools/testing/selftests/kvm/Makefile.kvm +++ b/tools/testing/selftests/kvm/Makefile.kvm @@ -167,6 +167,7 @@ TEST_GEN_PROGS_arm64 += arm64/vgic_irq TEST_GEN_PROGS_arm64 += arm64/vgic_lpi_stress TEST_GEN_PROGS_arm64 += arm64/vpmu_counter_access TEST_GEN_PROGS_arm64 += arm64/no-vgic-v3 +TEST_GEN_PROGS_arm64 += arm64/kvm-uuid TEST_GEN_PROGS_arm64 += access_tracking_perf_test TEST_GEN_PROGS_arm64 += arch_timer TEST_GEN_PROGS_arm64 += coalesced_io_test diff --git a/tools/testing/selftests/kvm/arm64/kvm-uuid.c b/tools/testing/selftests/kvm/arm64/kvm-uuid.c new file mode 100644 index 0000000000000..89d9c8b182ae5 --- /dev/null +++ b/tools/testing/selftests/kvm/arm64/kvm-uuid.c @@ -0,0 +1,67 @@ +#include <errno.h> +#include <linux/arm-smccc.h> +#include <asm/kvm.h> +#include <kvm_util.h> + +#include "processor.h" + +/* + * Do NOT redefine these constants, or try to replace them with some + * "common" version. They are hardcoded here to detect any potential + * breakage happening in the rest of the kernel. + * + * KVM UID value: 28b46fb6-2ec5-11e9-a9ca-4b564d003a74 + */ +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0 0xb66fb428U +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1 0xe911c52eU +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2 0x564bcaa9U +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3 0x743a004dU + +static void guest_code(void) +{ + struct arm_smccc_res res = {}; + + smccc_hvc(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, 0, 0, 0, 0, 0, 0, 0, &res); + + __GUEST_ASSERT(res.a0 != SMCCC_RET_NOT_SUPPORTED, "a0 = %lx\n", res.a0); + __GUEST_ASSERT(res.a0 == ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0 && + res.a1 == ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1 && + res.a2 == ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2 && + res.a3 == ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3, + "Unexpected KVM-specific UID %lx %lx %lx %lx\n", res.a0, res.a1, res.a2, res.a3); + GUEST_DONE(); +} + +int main (int argc, char *argv[]) +{ + struct kvm_vcpu *vcpu; + struct kvm_vm *vm; + struct ucall uc; + bool guest_done = false; + + vm = vm_create_with_one_vcpu(&vcpu, guest_code); + + while (!guest_done) { + vcpu_run(vcpu); + + switch (get_ucall(vcpu, &uc)) { + case UCALL_SYNC: + break; + case UCALL_DONE: + guest_done = true; + break; + case UCALL_ABORT: + REPORT_GUEST_ASSERT(uc); + break; + case UCALL_PRINTF: + printf("%s", uc.buffer); + break; + default: + TEST_FAIL("Unexpected guest exit"); + } + } + + kvm_vm_free(vm); + + return 0; +} -- 2.39.2 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] KVM: arm64: selftest: Add standalone test checking for KVM's own UUID 2025-07-21 15:51 [PATCH] KVM: arm64: selftest: Add standalone test checking for KVM's own UUID Marc Zyngier @ 2025-07-22 9:18 ` Andrew Jones 2025-07-22 15:47 ` Marc Zyngier 2025-08-06 17:10 ` Marc Zyngier 2025-07-22 14:39 ` Sebastian Ott 1 sibling, 2 replies; 5+ messages in thread From: Andrew Jones @ 2025-07-22 9:18 UTC (permalink / raw) To: Marc Zyngier Cc: kvmarm, kvm, linux-arm-kernel, linux-kernel, Joey Gouly, Suzuki K Poulose, Oliver Upton, Zenghui Yu, Will Deacon, Mark Rutland, jackabt Hi Marc, On Mon, Jul 21, 2025 at 04:51:36PM +0100, Marc Zyngier wrote: > Tinkering with UUIDs is a perilious task, and the KVM UUID gets > broken at times. In order to spot this early enough, add a selftest > that will shout if the expected value isn't found. > > Signed-off-by: Marc Zyngier <maz@kernel.org> > Link: https://lore.kernel.org/r/20250721130558.50823-1-jackabt.amazon@gmail.com > --- > tools/testing/selftests/kvm/Makefile.kvm | 1 + > tools/testing/selftests/kvm/arm64/kvm-uuid.c | 67 ++++++++++++++++++++ > 2 files changed, 68 insertions(+) > create mode 100644 tools/testing/selftests/kvm/arm64/kvm-uuid.c > > diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm > index ce817a975e50a..e1eb1ba238a2a 100644 > --- a/tools/testing/selftests/kvm/Makefile.kvm > +++ b/tools/testing/selftests/kvm/Makefile.kvm > @@ -167,6 +167,7 @@ TEST_GEN_PROGS_arm64 += arm64/vgic_irq > TEST_GEN_PROGS_arm64 += arm64/vgic_lpi_stress > TEST_GEN_PROGS_arm64 += arm64/vpmu_counter_access > TEST_GEN_PROGS_arm64 += arm64/no-vgic-v3 > +TEST_GEN_PROGS_arm64 += arm64/kvm-uuid > TEST_GEN_PROGS_arm64 += access_tracking_perf_test > TEST_GEN_PROGS_arm64 += arch_timer > TEST_GEN_PROGS_arm64 += coalesced_io_test > diff --git a/tools/testing/selftests/kvm/arm64/kvm-uuid.c b/tools/testing/selftests/kvm/arm64/kvm-uuid.c > new file mode 100644 > index 0000000000000..89d9c8b182ae5 > --- /dev/null > +++ b/tools/testing/selftests/kvm/arm64/kvm-uuid.c > @@ -0,0 +1,67 @@ > +#include <errno.h> > +#include <linux/arm-smccc.h> > +#include <asm/kvm.h> > +#include <kvm_util.h> > + > +#include "processor.h" > + > +/* > + * Do NOT redefine these constants, or try to replace them with some > + * "common" version. They are hardcoded here to detect any potential > + * breakage happening in the rest of the kernel. > + * > + * KVM UID value: 28b46fb6-2ec5-11e9-a9ca-4b564d003a74 > + */ > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0 0xb66fb428U > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1 0xe911c52eU > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2 0x564bcaa9U > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3 0x743a004dU > + > +static void guest_code(void) > +{ > + struct arm_smccc_res res = {}; > + > + smccc_hvc(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, 0, 0, 0, 0, 0, 0, 0, &res); > + > + __GUEST_ASSERT(res.a0 != SMCCC_RET_NOT_SUPPORTED, "a0 = %lx\n", res.a0); Should this check res.a0 == SMCCC_RET_SUCCESS instead? > + __GUEST_ASSERT(res.a0 == ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0 && > + res.a1 == ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1 && > + res.a2 == ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2 && > + res.a3 == ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3, > + "Unexpected KVM-specific UID %lx %lx %lx %lx\n", res.a0, res.a1, res.a2, res.a3); > + GUEST_DONE(); > +} > + > +int main (int argc, char *argv[]) > +{ > + struct kvm_vcpu *vcpu; > + struct kvm_vm *vm; > + struct ucall uc; > + bool guest_done = false; > + > + vm = vm_create_with_one_vcpu(&vcpu, guest_code); > + > + while (!guest_done) { > + vcpu_run(vcpu); > + > + switch (get_ucall(vcpu, &uc)) { > + case UCALL_SYNC: > + break; > + case UCALL_DONE: > + guest_done = true; > + break; > + case UCALL_ABORT: > + REPORT_GUEST_ASSERT(uc); > + break; > + case UCALL_PRINTF: > + printf("%s", uc.buffer); > + break; > + default: > + TEST_FAIL("Unexpected guest exit"); > + } > + } This is becoming a very common and useful pattern. I wonder if it's time for a ucall helper static void ucall_vcpu_run(struct kvm_vcpu *vcpu, void (*sync_func)(struct kvm_vcpu *, void *), void *sync_data) { bool guest_done = false; struct ucall uc; while (!guest_done) { vcpu_run(vcpu); switch (get_ucall(vcpu, &uc)) { case UCALL_SYNC: if (sync_func) sync_func(vcpu, sync_data); break; case UCALL_DONE: guest_done = true; break; case UCALL_ABORT: REPORT_GUEST_ASSERT(uc); break; case UCALL_PRINTF: printf("%s", uc.buffer); break; default: TEST_FAIL("Unexpected guest exit"); } } } Thanks, drew > + > + kvm_vm_free(vm); > + > + return 0; > +} > -- > 2.39.2 > ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] KVM: arm64: selftest: Add standalone test checking for KVM's own UUID 2025-07-22 9:18 ` Andrew Jones @ 2025-07-22 15:47 ` Marc Zyngier 2025-08-06 17:10 ` Marc Zyngier 1 sibling, 0 replies; 5+ messages in thread From: Marc Zyngier @ 2025-07-22 15:47 UTC (permalink / raw) To: Andrew Jones Cc: kvmarm, kvm, linux-arm-kernel, linux-kernel, Joey Gouly, Suzuki K Poulose, Oliver Upton, Zenghui Yu, Will Deacon, Mark Rutland, jackabt On Tue, 22 Jul 2025 10:18:10 +0100, Andrew Jones <ajones@ventanamicro.com> wrote: > > Hi Marc, > > On Mon, Jul 21, 2025 at 04:51:36PM +0100, Marc Zyngier wrote: > > Tinkering with UUIDs is a perilious task, and the KVM UUID gets > > broken at times. In order to spot this early enough, add a selftest > > that will shout if the expected value isn't found. > > > > Signed-off-by: Marc Zyngier <maz@kernel.org> > > Link: https://lore.kernel.org/r/20250721130558.50823-1-jackabt.amazon@gmail.com > > --- > > tools/testing/selftests/kvm/Makefile.kvm | 1 + > > tools/testing/selftests/kvm/arm64/kvm-uuid.c | 67 ++++++++++++++++++++ > > 2 files changed, 68 insertions(+) > > create mode 100644 tools/testing/selftests/kvm/arm64/kvm-uuid.c > > > > diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm > > index ce817a975e50a..e1eb1ba238a2a 100644 > > --- a/tools/testing/selftests/kvm/Makefile.kvm > > +++ b/tools/testing/selftests/kvm/Makefile.kvm > > @@ -167,6 +167,7 @@ TEST_GEN_PROGS_arm64 += arm64/vgic_irq > > TEST_GEN_PROGS_arm64 += arm64/vgic_lpi_stress > > TEST_GEN_PROGS_arm64 += arm64/vpmu_counter_access > > TEST_GEN_PROGS_arm64 += arm64/no-vgic-v3 > > +TEST_GEN_PROGS_arm64 += arm64/kvm-uuid > > TEST_GEN_PROGS_arm64 += access_tracking_perf_test > > TEST_GEN_PROGS_arm64 += arch_timer > > TEST_GEN_PROGS_arm64 += coalesced_io_test > > diff --git a/tools/testing/selftests/kvm/arm64/kvm-uuid.c b/tools/testing/selftests/kvm/arm64/kvm-uuid.c > > new file mode 100644 > > index 0000000000000..89d9c8b182ae5 > > --- /dev/null > > +++ b/tools/testing/selftests/kvm/arm64/kvm-uuid.c > > @@ -0,0 +1,67 @@ > > +#include <errno.h> > > +#include <linux/arm-smccc.h> > > +#include <asm/kvm.h> > > +#include <kvm_util.h> > > + > > +#include "processor.h" > > + > > +/* > > + * Do NOT redefine these constants, or try to replace them with some > > + * "common" version. They are hardcoded here to detect any potential > > + * breakage happening in the rest of the kernel. > > + * > > + * KVM UID value: 28b46fb6-2ec5-11e9-a9ca-4b564d003a74 > > + */ > > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0 0xb66fb428U > > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1 0xe911c52eU > > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2 0x564bcaa9U > > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3 0x743a004dU > > + > > +static void guest_code(void) > > +{ > > + struct arm_smccc_res res = {}; > > + > > + smccc_hvc(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, 0, 0, 0, 0, 0, 0, 0, &res); > > + > > + __GUEST_ASSERT(res.a0 != SMCCC_RET_NOT_SUPPORTED, "a0 = %lx\n", res.a0); > > Should this check res.a0 == SMCCC_RET_SUCCESS instead? Yeah, probably. > > > + __GUEST_ASSERT(res.a0 == ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0 && > > + res.a1 == ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1 && > > + res.a2 == ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2 && > > + res.a3 == ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3, > > + "Unexpected KVM-specific UID %lx %lx %lx %lx\n", res.a0, res.a1, res.a2, res.a3); > > + GUEST_DONE(); > > +} > > + > > +int main (int argc, char *argv[]) > > +{ > > + struct kvm_vcpu *vcpu; > > + struct kvm_vm *vm; > > + struct ucall uc; > > + bool guest_done = false; > > + > > + vm = vm_create_with_one_vcpu(&vcpu, guest_code); > > + > > + while (!guest_done) { > > + vcpu_run(vcpu); > > + > > + switch (get_ucall(vcpu, &uc)) { > > + case UCALL_SYNC: > > + break; > > + case UCALL_DONE: > > + guest_done = true; > > + break; > > + case UCALL_ABORT: > > + REPORT_GUEST_ASSERT(uc); > > + break; > > + case UCALL_PRINTF: > > + printf("%s", uc.buffer); > > + break; > > + default: > > + TEST_FAIL("Unexpected guest exit"); > > + } > > + } > > This is becoming a very common and useful pattern. I wonder if it's time > for a ucall helper > > static void ucall_vcpu_run(struct kvm_vcpu *vcpu, > void (*sync_func)(struct kvm_vcpu *, void *), > void *sync_data) > { > bool guest_done = false; > struct ucall uc; > > while (!guest_done) { > vcpu_run(vcpu); > > switch (get_ucall(vcpu, &uc)) { > case UCALL_SYNC: > if (sync_func) > sync_func(vcpu, sync_data); > break; > case UCALL_DONE: > guest_done = true; > break; > case UCALL_ABORT: > REPORT_GUEST_ASSERT(uc); > break; > case UCALL_PRINTF: > printf("%s", uc.buffer); > break; > default: > TEST_FAIL("Unexpected guest exit"); > } > } > } Honestly, I don't know. My understanding is that the common kvm selftest code is now mostly a pile of x86-specific stuff, and I've made it a goal not to touch any of it. Thanks, M. -- Without deviation from the norm, progress is not possible. ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] KVM: arm64: selftest: Add standalone test checking for KVM's own UUID 2025-07-22 9:18 ` Andrew Jones 2025-07-22 15:47 ` Marc Zyngier @ 2025-08-06 17:10 ` Marc Zyngier 1 sibling, 0 replies; 5+ messages in thread From: Marc Zyngier @ 2025-08-06 17:10 UTC (permalink / raw) To: Andrew Jones Cc: kvmarm, kvm, linux-arm-kernel, linux-kernel, Joey Gouly, Suzuki K Poulose, Oliver Upton, Zenghui Yu, Will Deacon, Mark Rutland, jackabt On Tue, 22 Jul 2025 10:18:10 +0100, Andrew Jones <ajones@ventanamicro.com> wrote: > > Hi Marc, > > On Mon, Jul 21, 2025 at 04:51:36PM +0100, Marc Zyngier wrote: > > Tinkering with UUIDs is a perilious task, and the KVM UUID gets > > broken at times. In order to spot this early enough, add a selftest > > that will shout if the expected value isn't found. > > > > Signed-off-by: Marc Zyngier <maz@kernel.org> > > Link: https://lore.kernel.org/r/20250721130558.50823-1-jackabt.amazon@gmail.com > > --- > > tools/testing/selftests/kvm/Makefile.kvm | 1 + > > tools/testing/selftests/kvm/arm64/kvm-uuid.c | 67 ++++++++++++++++++++ > > 2 files changed, 68 insertions(+) > > create mode 100644 tools/testing/selftests/kvm/arm64/kvm-uuid.c > > > > diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm > > index ce817a975e50a..e1eb1ba238a2a 100644 > > --- a/tools/testing/selftests/kvm/Makefile.kvm > > +++ b/tools/testing/selftests/kvm/Makefile.kvm > > @@ -167,6 +167,7 @@ TEST_GEN_PROGS_arm64 += arm64/vgic_irq > > TEST_GEN_PROGS_arm64 += arm64/vgic_lpi_stress > > TEST_GEN_PROGS_arm64 += arm64/vpmu_counter_access > > TEST_GEN_PROGS_arm64 += arm64/no-vgic-v3 > > +TEST_GEN_PROGS_arm64 += arm64/kvm-uuid > > TEST_GEN_PROGS_arm64 += access_tracking_perf_test > > TEST_GEN_PROGS_arm64 += arch_timer > > TEST_GEN_PROGS_arm64 += coalesced_io_test > > diff --git a/tools/testing/selftests/kvm/arm64/kvm-uuid.c b/tools/testing/selftests/kvm/arm64/kvm-uuid.c > > new file mode 100644 > > index 0000000000000..89d9c8b182ae5 > > --- /dev/null > > +++ b/tools/testing/selftests/kvm/arm64/kvm-uuid.c > > @@ -0,0 +1,67 @@ > > +#include <errno.h> > > +#include <linux/arm-smccc.h> > > +#include <asm/kvm.h> > > +#include <kvm_util.h> > > + > > +#include "processor.h" > > + > > +/* > > + * Do NOT redefine these constants, or try to replace them with some > > + * "common" version. They are hardcoded here to detect any potential > > + * breakage happening in the rest of the kernel. > > + * > > + * KVM UID value: 28b46fb6-2ec5-11e9-a9ca-4b564d003a74 > > + */ > > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0 0xb66fb428U > > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1 0xe911c52eU > > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2 0x564bcaa9U > > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3 0x743a004dU > > + > > +static void guest_code(void) > > +{ > > + struct arm_smccc_res res = {}; > > + > > + smccc_hvc(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, 0, 0, 0, 0, 0, 0, 0, &res); > > + > > + __GUEST_ASSERT(res.a0 != SMCCC_RET_NOT_SUPPORTED, "a0 = %lx\n", res.a0); > > Should this check res.a0 == SMCCC_RET_SUCCESS instead? Sorry for the delay, but now that I'm awake, it is obvious this doesn't work at all. A0-A3 contain the full UID. While checking for A0 != NOT_SUPPORTED is valid, checking for A0 == SUCCESS cannot work on KVM (we'd get 0xb66fb428 instead of 0). So actually, this assertion is meaningless, and I'm dropping it. Thanks, M. -- Without deviation from the norm, progress is not possible. ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] KVM: arm64: selftest: Add standalone test checking for KVM's own UUID 2025-07-21 15:51 [PATCH] KVM: arm64: selftest: Add standalone test checking for KVM's own UUID Marc Zyngier 2025-07-22 9:18 ` Andrew Jones @ 2025-07-22 14:39 ` Sebastian Ott 1 sibling, 0 replies; 5+ messages in thread From: Sebastian Ott @ 2025-07-22 14:39 UTC (permalink / raw) To: Marc Zyngier Cc: kvmarm, kvm, linux-arm-kernel, linux-kernel, Joey Gouly, Suzuki K Poulose, Oliver Upton, Zenghui Yu, Will Deacon, Mark Rutland, jackabt On Mon, 21 Jul 2025, Marc Zyngier wrote: > Tinkering with UUIDs is a perilious task, and the KVM UUID gets > broken at times. In order to spot this early enough, add a selftest > that will shout if the expected value isn't found. > > Signed-off-by: Marc Zyngier <maz@kernel.org> > Link: https://lore.kernel.org/r/20250721130558.50823-1-jackabt.amazon@gmail.com Reviewed-by: Sebastian Ott <sebott@redhat.com> ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2025-08-06 17:10 UTC | newest] Thread overview: 5+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2025-07-21 15:51 [PATCH] KVM: arm64: selftest: Add standalone test checking for KVM's own UUID Marc Zyngier 2025-07-22 9:18 ` Andrew Jones 2025-07-22 15:47 ` Marc Zyngier 2025-08-06 17:10 ` Marc Zyngier 2025-07-22 14:39 ` Sebastian Ott
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