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* [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
  2025-07-21 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

* 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

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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