[PATCH v3 06/13] KVM: selftests: Assert success in vmptrst(), kill off vmptrstz()

From: Sean Christopherson

Date: Wed Aug 26 2026 - 19:39:53 EST


Assert success in vmptrst() instead of punting to the caller, as literally
every user expects VMPTRST to succeed (and because '0' is a valid physical
address).

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
tools/testing/selftests/kvm/include/x86/vmx.h | 19 ++++---------------
.../testing/selftests/kvm/x86/hyperv_evmcs.c | 4 ++--
tools/testing/selftests/kvm/x86/state_test.c | 8 ++++----
.../kvm/x86/vmx_preemption_timer_test.c | 2 +-
4 files changed, 11 insertions(+), 22 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86/vmx.h b/tools/testing/selftests/kvm/include/x86/vmx.h
index a161dbee7e04..04f638fcd3ba 100644
--- a/tools/testing/selftests/kvm/include/x86/vmx.h
+++ b/tools/testing/selftests/kvm/include/x86/vmx.h
@@ -366,27 +366,16 @@ static inline int __vmptrld(u64 vmcs_pa)
return vector ? vector : failed ? -EINVAL : 0;
}

-static inline int vmptrst(u64 *value)
+static inline u64 vmptrst(void)
{
- u64 tmp;
+ u64 value = 0;
u8 ret;

__asm__ __volatile__("vmptrst %[value]; setna %[ret]"
- : [value]"=m"(tmp), [ret]"=rm"(ret)
+ : [value]"=m"(value), [ret]"=rm"(ret)
: : "cc", "memory");

- *value = tmp;
- return ret;
-}
-
-/*
- * A wrapper around vmptrst that ignores errors and returns zero if the
- * vmptrst instruction fails.
- */
-static inline u64 vmptrstz(void)
-{
- u64 value = 0;
- vmptrst(&value);
+ __GUEST_ASSERT(!ret, "vmptrst failed");
return value;
}

diff --git a/tools/testing/selftests/kvm/x86/hyperv_evmcs.c b/tools/testing/selftests/kvm/x86/hyperv_evmcs.c
index f953a9755a76..0c9cf620c87d 100644
--- a/tools/testing/selftests/kvm/x86/hyperv_evmcs.c
+++ b/tools/testing/selftests/kvm/x86/hyperv_evmcs.c
@@ -97,7 +97,7 @@ void guest_code(struct vmx_pages *vmx_pages, struct hyperv_test_pages *hv_pages,
GUEST_SYNC(3);
GUEST_ASSERT(load_evmcs(hv_pages));
/* VMPTRST returns -1 until VMLAUNCH with eVMCS ptr set */
- GUEST_ASSERT(vmptrstz() == -1);
+ GUEST_ASSERT(vmptrst() == -1);

GUEST_SYNC(4);

@@ -123,7 +123,7 @@ void guest_code(struct vmx_pages *vmx_pages, struct hyperv_test_pages *hv_pages,
GUEST_ASSERT(!vmlaunch());
GUEST_ASSERT_EQ(vmreadz(VM_EXIT_REASON), EXIT_REASON_EXCEPTION_NMI);
GUEST_ASSERT_EQ((vmreadz(VM_EXIT_INTR_INFO) & 0xff), NMI_VECTOR);
- GUEST_ASSERT(vmptrstz() == hv_pages->enlightened_vmcs_gpa);
+ GUEST_ASSERT(vmptrst() == hv_pages->enlightened_vmcs_gpa);

/*
* NMI forces L2->L1 exit, resuming L2 and hope that EVMCS is
diff --git a/tools/testing/selftests/kvm/x86/state_test.c b/tools/testing/selftests/kvm/x86/state_test.c
index 4a1056a6cb8d..9d4e0c1f7c18 100644
--- a/tools/testing/selftests/kvm/x86/state_test.c
+++ b/tools/testing/selftests/kvm/x86/state_test.c
@@ -78,17 +78,17 @@ static void vmx_l1_guest_code(struct vmx_pages *vmx_pages)
GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
GUEST_SYNC(3);
GUEST_ASSERT(load_vmcs(vmx_pages));
- GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);
+ GUEST_ASSERT(vmptrst() == vmx_pages->vmcs_gpa);

GUEST_SYNC(4);
- GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);
+ GUEST_ASSERT(vmptrst() == vmx_pages->vmcs_gpa);

prepare_vmcs(vmx_pages, vmx_l2_guest_code);

GUEST_SYNC(5);
- GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);
+ GUEST_ASSERT(vmptrst() == vmx_pages->vmcs_gpa);
GUEST_ASSERT(!vmlaunch());
- GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);
+ GUEST_ASSERT(vmptrst() == vmx_pages->vmcs_gpa);
GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);

/* Check that the launched state is preserved. */
diff --git a/tools/testing/selftests/kvm/x86/vmx_preemption_timer_test.c b/tools/testing/selftests/kvm/x86/vmx_preemption_timer_test.c
index eb8021c33cd4..523aab667d85 100644
--- a/tools/testing/selftests/kvm/x86/vmx_preemption_timer_test.c
+++ b/tools/testing/selftests/kvm/x86/vmx_preemption_timer_test.c
@@ -73,7 +73,7 @@ void l1_guest_code(struct vmx_pages *vmx_pages)
GUEST_ASSERT(vmx_pages->vmcs_gpa);
GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
GUEST_ASSERT(load_vmcs(vmx_pages));
- GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);
+ GUEST_ASSERT(vmptrst() == vmx_pages->vmcs_gpa);

prepare_vmcs(vmx_pages, l2_guest_code);

--
2.55.0.887.g758fc8c411-goog