From: Sean Christopherson <seanjc@google.com>
To: Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
f734222792@gmail.com, Vitaly Kuznetsov <vkuznets@redhat.com>,
Sashiko Bot <sashiko-bot@kernel.org>,
Yosry Ahmed <yosry@kernel.org>
Subject: [PATCH v4 16/17] KVM: selftests: Always assert that vmwrite() succeeds
Date: Thu, 3 Sep 2026 17:24:22 -0700 [thread overview]
Message-ID: <20260904002423.3154436-17-seanjc@google.com> (raw)
In-Reply-To: <20260904002423.3154436-1-seanjc@google.com>
Assert that vmwrite() succeeds instead of forcing all callers to do the
same (or as is much more common, ignoring VM-Fail and likely letting the
test fail in weird ways), opportunistically provide a more verbose error
message on failure.
All usage of vmwrite() "guarantees" success, either because the field in
question is unconditionally emulated by KVM, by virtue of earlier support
checks, or by falling over (later in the test) if the VMWRITE fails.
Cc: Yosry Ahmed <yosry@kernel.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
tools/testing/selftests/kvm/include/x86/vmx.h | 5 +++--
tools/testing/selftests/kvm/x86/aperfmperf_test.c | 2 +-
tools/testing/selftests/kvm/x86/kvm_buslock_test.c | 2 +-
.../testing/selftests/kvm/x86/nested_emulation_test.c | 6 +++---
.../testing/selftests/kvm/x86/nested_exceptions_test.c | 10 +++++-----
.../selftests/kvm/x86/save_restore_pf_stress_test.c | 2 +-
tools/testing/selftests/kvm/x86/state_test.c | 4 ++--
.../selftests/kvm/x86/vmx_preemption_timer_test.c | 8 +++-----
8 files changed, 19 insertions(+), 20 deletions(-)
diff --git a/tools/testing/selftests/kvm/include/x86/vmx.h b/tools/testing/selftests/kvm/include/x86/vmx.h
index 40111db580a8..be10028c51b9 100644
--- a/tools/testing/selftests/kvm/include/x86/vmx.h
+++ b/tools/testing/selftests/kvm/include/x86/vmx.h
@@ -429,9 +429,10 @@ static __always_inline int __vmwrite(u64 encoding, u64 value)
return ret;
}
-static inline int vmwrite(u64 encoding, u64 value)
+static inline void vmwrite(u64 encoding, u64 value)
{
- return __vmwrite(encoding, value);
+ __GUEST_ASSERT(!__vmwrite(encoding, value),
+ "vmwrite[0x%lx] = 0x%lx hit VM-Fail", encoding, value);
}
static inline u32 vmcs_revision(void)
diff --git a/tools/testing/selftests/kvm/x86/aperfmperf_test.c b/tools/testing/selftests/kvm/x86/aperfmperf_test.c
index a082658c1e48..7761a8bdf5f6 100644
--- a/tools/testing/selftests/kvm/x86/aperfmperf_test.c
+++ b/tools/testing/selftests/kvm/x86/aperfmperf_test.c
@@ -82,7 +82,7 @@ static void l1_vmx_code(struct vmx_pages *vmx)
vmwrite(CPU_BASED_VM_EXEC_CONTROL,
vmreadz(CPU_BASED_VM_EXEC_CONTROL) | CPU_BASED_USE_MSR_BITMAPS);
- GUEST_ASSERT(!vmwrite(GUEST_RIP, (u64)l2_guest_code));
+ vmwrite(GUEST_RIP, (u64)l2_guest_code);
vmlaunch();
}
diff --git a/tools/testing/selftests/kvm/x86/kvm_buslock_test.c b/tools/testing/selftests/kvm/x86/kvm_buslock_test.c
index 337d3c28bc6d..e1d2730b16ba 100644
--- a/tools/testing/selftests/kvm/x86/kvm_buslock_test.c
+++ b/tools/testing/selftests/kvm/x86/kvm_buslock_test.c
@@ -47,7 +47,7 @@ static void l1_vmx_code(struct vmx_pages *vmx)
prepare_vmcs(vmx, NULL);
- GUEST_ASSERT(!vmwrite(GUEST_RIP, (u64)l2_guest_code));
+ vmwrite(GUEST_RIP, (u64)l2_guest_code);
vmlaunch();
}
diff --git a/tools/testing/selftests/kvm/x86/nested_emulation_test.c b/tools/testing/selftests/kvm/x86/nested_emulation_test.c
index 51e2f7e386c1..009932b1604e 100644
--- a/tools/testing/selftests/kvm/x86/nested_emulation_test.c
+++ b/tools/testing/selftests/kvm/x86/nested_emulation_test.c
@@ -70,9 +70,9 @@ static void guest_code(void *test_data)
load_vmcs(test_data);
prepare_vmcs(test_data, NULL);
- GUEST_ASSERT(!vmwrite(GUEST_IDTR_LIMIT, 0));
- GUEST_ASSERT(!vmwrite(GUEST_RIP, (u64)l2_guest_code));
- GUEST_ASSERT(!vmwrite(EXCEPTION_BITMAP, 0));
+ vmwrite(GUEST_IDTR_LIMIT, 0);
+ vmwrite(GUEST_RIP, (u64)l2_guest_code);
+ vmwrite(EXCEPTION_BITMAP, 0);
vmwrite(CPU_BASED_VM_EXEC_CONTROL, vmreadz(CPU_BASED_VM_EXEC_CONTROL) |
CPU_BASED_PAUSE_EXITING |
diff --git a/tools/testing/selftests/kvm/x86/nested_exceptions_test.c b/tools/testing/selftests/kvm/x86/nested_exceptions_test.c
index 031eb84229dc..d0beaa7b280b 100644
--- a/tools/testing/selftests/kvm/x86/nested_exceptions_test.c
+++ b/tools/testing/selftests/kvm/x86/nested_exceptions_test.c
@@ -110,7 +110,7 @@ static void l1_svm_code(struct svm_test_data *svm)
static void vmx_run_l2(void *l2_code, int vector, u32 error_code)
{
- GUEST_ASSERT(!vmwrite(GUEST_RIP, (u64)l2_code));
+ vmwrite(GUEST_RIP, (u64)l2_code);
if (vector == SS_VECTOR)
vmlaunch();
@@ -133,21 +133,21 @@ static void l1_vmx_code(struct vmx_pages *vmx)
load_vmcs(vmx);
prepare_vmcs(vmx, NULL);
- GUEST_ASSERT_EQ(vmwrite(GUEST_IDTR_LIMIT, 0), 0);
+ vmwrite(GUEST_IDTR_LIMIT, 0);
/*
* VMX disallows injecting an exception with error_code[31:16] != 0,
* and hardware will never generate a VM-Exit with bits 31:16 set.
* KVM should likewise truncate the "bad" userspace value.
*/
- GUEST_ASSERT_EQ(vmwrite(EXCEPTION_BITMAP, INTERCEPT_SS_GP_DF), 0);
+ vmwrite(EXCEPTION_BITMAP, INTERCEPT_SS_GP_DF);
vmx_run_l2(l2_ss_pending_test, SS_VECTOR, (u16)SS_ERROR_CODE);
vmx_run_l2(l2_ss_injected_gp_test, GP_VECTOR, GP_ERROR_CODE_INTEL);
- GUEST_ASSERT_EQ(vmwrite(EXCEPTION_BITMAP, INTERCEPT_SS_DF), 0);
+ vmwrite(EXCEPTION_BITMAP, INTERCEPT_SS_DF);
vmx_run_l2(l2_ss_injected_df_test, DF_VECTOR, DF_ERROR_CODE);
- GUEST_ASSERT_EQ(vmwrite(EXCEPTION_BITMAP, INTERCEPT_SS), 0);
+ vmwrite(EXCEPTION_BITMAP, INTERCEPT_SS);
vmx_run_l2(l2_ss_injected_tf_test, FAKE_TRIPLE_FAULT_VECTOR, 0);
GUEST_ASSERT_EQ(vmreadz(VM_EXIT_REASON), EXIT_REASON_TRIPLE_FAULT);
diff --git a/tools/testing/selftests/kvm/x86/save_restore_pf_stress_test.c b/tools/testing/selftests/kvm/x86/save_restore_pf_stress_test.c
index f88427e925fc..e728f040916f 100644
--- a/tools/testing/selftests/kvm/x86/save_restore_pf_stress_test.c
+++ b/tools/testing/selftests/kvm/x86/save_restore_pf_stress_test.c
@@ -102,7 +102,7 @@ static void l1_vmx_code(struct vmx_pages *vmx)
load_vmcs(vmx);
prepare_vmcs(vmx, guest_access_memory);
- GUEST_ASSERT(!vmwrite(EXCEPTION_BITMAP, BIT(UD_VECTOR)));
+ vmwrite(EXCEPTION_BITMAP, BIT(UD_VECTOR));
vmlaunch();
while (1) {
diff --git a/tools/testing/selftests/kvm/x86/state_test.c b/tools/testing/selftests/kvm/x86/state_test.c
index 38c9689ac601..7cb1d160e2d9 100644
--- a/tools/testing/selftests/kvm/x86/state_test.c
+++ b/tools/testing/selftests/kvm/x86/state_test.c
@@ -62,10 +62,10 @@ void vmx_l2_guest_code(void)
GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffee);
GUEST_SYNC(10);
GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffee);
- GUEST_ASSERT(!vmwrite(GUEST_RIP, 0xc0fffee));
+ vmwrite(GUEST_RIP, 0xc0fffee);
GUEST_SYNC(11);
GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0fffee);
- GUEST_ASSERT(!vmwrite(GUEST_RIP, 0xc0ffffee));
+ vmwrite(GUEST_RIP, 0xc0ffffee);
GUEST_SYNC(12);
/* Done, exit to L1 and never come back. */
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 cda53df33888..c5f9d9879f61 100644
--- a/tools/testing/selftests/kvm/x86/vmx_preemption_timer_test.c
+++ b/tools/testing/selftests/kvm/x86/vmx_preemption_timer_test.c
@@ -97,12 +97,10 @@ void l1_guest_code(struct vmx_pages *vmx_pages)
/*
* Turn on PIN control and resume the guest
*/
- GUEST_ASSERT(!vmwrite(PIN_BASED_VM_EXEC_CONTROL,
- vmreadz(PIN_BASED_VM_EXEC_CONTROL) |
- PIN_BASED_VMX_PREEMPTION_TIMER));
+ vmwrite(PIN_BASED_VM_EXEC_CONTROL,
+ vmreadz(PIN_BASED_VM_EXEC_CONTROL) | PIN_BASED_VMX_PREEMPTION_TIMER);
- GUEST_ASSERT(!vmwrite(VMX_PREEMPTION_TIMER_VALUE,
- PREEMPTION_TIMER_VALUE));
+ vmwrite(VMX_PREEMPTION_TIMER_VALUE, PREEMPTION_TIMER_VALUE);
vmx_pt_rate = rdmsr(MSR_IA32_VMX_MISC) & 0x1F;
--
2.55.0.979.g7e5102b832-goog
next prev parent reply other threads:[~2026-09-04 0:24 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-04 0:24 [PATCH v4 00/17] KVM: nVMX: Adjust VMPTRLD/VMPTRST behavior with active eVMCS Sean Christopherson
2026-09-04 0:24 ` [PATCH v4 01/17] KVM: nVMX: Make VMPTRLD result in #UD when eVMCS is used Sean Christopherson
2026-09-04 0:24 ` [PATCH v4 02/17] KVM: nVMX: Make VMPTRST return eVMCS GPA when it " Sean Christopherson
2026-09-04 0:24 ` [PATCH v4 03/17] KVM: selftests: Don't clobber RFLAGS in happy path of __KVM_ASM_SAFE() Sean Christopherson
2026-09-04 0:24 ` [PATCH v4 04/17] KVM: selftests: Adapt to the updated VMPTRST behavior when eVMCS is used Sean Christopherson
2026-09-04 0:24 ` [PATCH v4 05/17] KVM: selftests: Check VMPTRLD with active eVMCS Sean Christopherson
2026-09-04 0:24 ` [PATCH v4 06/17] KVM: selftests: Assert success in vmptrst(), kill off vmptrstz() Sean Christopherson
2026-09-04 0:24 ` [PATCH v4 07/17] KVM: selftests: Always assert that vmxon() and prepare_for_vmx_operation() succeed Sean Christopherson
2026-09-04 0:24 ` [PATCH v4 08/17] KVM: selftests: Always assert that vmclear() succeeds Sean Christopherson
2026-09-04 0:24 ` [PATCH v4 09/17] KVM: selftests: Always assert that vmptrld() succeeds Sean Christopherson
2026-09-04 0:24 ` [PATCH v4 10/17] KVM: selftests: Drop useless return code from load_vmcs() Sean Christopherson
2026-09-04 0:24 ` [PATCH v4 11/17] KVM: selftests: Add macros to handle simple VMX instructions Sean Christopherson
2026-09-04 0:24 ` [PATCH v4 12/17] KVM: selftests: Drop dead return code from evmcs_vmptrld() and load_evmcs() Sean Christopherson
2026-09-04 0:24 ` [PATCH v4 13/17] KVM: selftests: Dedup assembly code for VMLAUNCH and VMRESUME Sean Christopherson
2026-09-04 0:24 ` [PATCH v4 14/17] KVM: selftests: Assert success in vmlaunch() and vmresume() Sean Christopherson
2026-09-04 0:35 ` sashiko-bot
2026-09-04 0:24 ` [PATCH v4 15/17] KVM: selftests: Add __vmwrite() and use it when initializing optional fields Sean Christopherson
2026-09-04 0:35 ` sashiko-bot
2026-09-04 0:24 ` Sean Christopherson [this message]
2026-09-04 0:24 ` [PATCH v4 17/17] KVM: selftests: Always assert that vmreadz() succeeds Sean Christopherson
2026-09-04 0:36 ` sashiko-bot
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