linux-kernel - [PATCH 5/5] KVM: selftests: Rely on KVM_RUN_NEEDS

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250111012450.1262638-6-seanjc@google.com>
Date: Fri, 10 Jan 2025 17:24:50 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>, Marc Zyngier <maz@...nel.org>, 
	Oliver Upton <oliver.upton@...ux.dev>, Michael Ellerman <mpe@...erman.id.au>, 
	Sean Christopherson <seanjc@...gle.com>
Cc: kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	kvmarm@...ts.linux.dev, linuxppc-dev@...ts.ozlabs.org, 
	linux-kernel@...r.kernel.org
Subject: [PATCH 5/5] KVM: selftests: Rely on KVM_RUN_NEEDS_COMPLETION to
 complete userspace exits

Add selftests coverage for KVM_RUN_NEEDS_COMPLETION by redoing KVM_RUN if
and only if KVM states that completion is required.

Opportunistically rename the helper to replace "io" with "exit", as exits
that require completion are no longer limited to I/O.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 tools/testing/selftests/kvm/include/kvm_util.h            | 8 ++++++--
 tools/testing/selftests/kvm/lib/kvm_util.c                | 4 ++++
 tools/testing/selftests/kvm/lib/ucall_common.c            | 2 +-
 tools/testing/selftests/kvm/lib/x86/processor.c           | 8 +-------
 tools/testing/selftests/kvm/x86/triple_fault_event_test.c | 3 +--
 5 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 78fd597c1b60..86e1850e4e49 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -29,6 +29,8 @@
 
 #define NSEC_PER_SEC 1000000000L
 
+extern bool kvm_has_needs_completion;
+
 struct userspace_mem_region {
 	struct kvm_userspace_memory_region2 region;
 	struct sparsebit *unused_phy_pages;
@@ -634,9 +636,11 @@ static inline int __vcpu_run(struct kvm_vcpu *vcpu)
 
 void vcpu_run_immediate_exit(struct kvm_vcpu *vcpu);
 
-static inline void vcpu_run_complete_io(struct kvm_vcpu *vcpu)
+static inline void vcpu_run_complete_exit(struct kvm_vcpu *vcpu)
 {
-	vcpu_run_immediate_exit(vcpu);
+	if (!kvm_has_needs_completion ||
+	    (vcpu->run->flags & KVM_RUN_NEEDS_COMPLETION))
+		vcpu_run_immediate_exit(vcpu);
 }
 
 struct kvm_reg_list *vcpu_get_reg_list(struct kvm_vcpu *vcpu);
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index c9a33766f673..95ac9b981049 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -19,6 +19,8 @@
 
 #define KVM_UTIL_MIN_PFN	2
 
+bool kvm_has_needs_completion;
+
 uint32_t guest_random_seed;
 struct guest_random_state guest_rng;
 static uint32_t last_guest_seed;
@@ -2253,6 +2255,8 @@ void __attribute((constructor)) kvm_selftest_init(void)
 	/* Tell stdout not to buffer its content. */
 	setbuf(stdout, NULL);
 
+	kvm_has_needs_completion = kvm_check_cap(KVM_CAP_NEEDS_COMPLETION);
+
 	guest_random_seed = last_guest_seed = random();
 	pr_info("Random seed: 0x%x\n", guest_random_seed);
 
diff --git a/tools/testing/selftests/kvm/lib/ucall_common.c b/tools/testing/selftests/kvm/lib/ucall_common.c
index 42151e571953..125584a94ba8 100644
--- a/tools/testing/selftests/kvm/lib/ucall_common.c
+++ b/tools/testing/selftests/kvm/lib/ucall_common.c
@@ -154,7 +154,7 @@ uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
 			    "Guest failed to allocate ucall struct");
 
 		memcpy(uc, addr, sizeof(*uc));
-		vcpu_run_complete_io(vcpu);
+		vcpu_run_complete_exit(vcpu);
 	} else {
 		memset(uc, 0, sizeof(*uc));
 	}
diff --git a/tools/testing/selftests/kvm/lib/x86/processor.c b/tools/testing/selftests/kvm/lib/x86/processor.c
index bd5a802fa7a5..1db4764e413b 100644
--- a/tools/testing/selftests/kvm/lib/x86/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86/processor.c
@@ -1077,13 +1077,7 @@ struct kvm_x86_state *vcpu_save_state(struct kvm_vcpu *vcpu)
 			    nested_size, sizeof(state->nested_));
 	}
 
-	/*
-	 * When KVM exits to userspace with KVM_EXIT_IO, KVM guarantees
-	 * guest state is consistent only after userspace re-enters the
-	 * kernel with KVM_RUN.  Complete IO prior to migrating state
-	 * to a new VM.
-	 */
-	vcpu_run_complete_io(vcpu);
+	vcpu_run_complete_exit(vcpu);
 
 	state = malloc(sizeof(*state) + msr_list->nmsrs * sizeof(state->msrs.entries[0]));
 	TEST_ASSERT(state, "-ENOMEM when allocating kvm state");
diff --git a/tools/testing/selftests/kvm/x86/triple_fault_event_test.c b/tools/testing/selftests/kvm/x86/triple_fault_event_test.c
index 56306a19144a..82d732788bc1 100644
--- a/tools/testing/selftests/kvm/x86/triple_fault_event_test.c
+++ b/tools/testing/selftests/kvm/x86/triple_fault_event_test.c
@@ -97,8 +97,7 @@ int main(void)
 	events.flags |= KVM_VCPUEVENT_VALID_TRIPLE_FAULT;
 	events.triple_fault.pending = true;
 	vcpu_events_set(vcpu, &events);
-	run->immediate_exit = true;
-	vcpu_run_complete_io(vcpu);
+	vcpu_run_complete_exit(vcpu);
 
 	vcpu_events_get(vcpu, &events);
 	TEST_ASSERT(events.flags & KVM_VCPUEVENT_VALID_TRIPLE_FAULT,
-- 
2.47.1.613.gc27f4b7a9f-goog