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Date:   Tue, 12 Dec 2023 12:46:42 -0800
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Subject: [RFC PATCH v5 27/29] KVM: selftests: Propagate KVM_EXIT_MEMORY_FAULT
 to userspace
From:   Sagi Shahar <sagis@google.com>
To:     linux-kselftest@vger.kernel.org,
        Ackerley Tng <ackerleytng@google.com>,
        Ryan Afranji <afranji@google.com>,
        Erdem Aktas <erdemaktas@google.com>,
        Sagi Shahar <sagis@google.com>,
        Isaku Yamahata <isaku.yamahata@intel.com>
Cc:     Sean Christopherson <seanjc@google.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Shuah Khan <shuah@kernel.org>, Peter Gonda <pgonda@google.com>,
        Haibo Xu <haibo1.xu@intel.com>,
        Chao Peng <chao.p.peng@linux.intel.com>,
        Vishal Annapurve <vannapurve@google.com>,
        Roger Wang <runanwang@google.com>,
        Vipin Sharma <vipinsh@google.com>, jmattson@google.com,
        dmatlack@google.com, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org, linux-mm@kvack.org
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Precedence: bulk

Allow userspace to handle KVM_EXIT_MEMORY_FAULT instead of triggering
TEST_ASSERT.

From the KVM_EXIT_MEMORY_FAULT documentation:
Note!  KVM_EXIT_MEMORY_FAULT is unique among all KVM exit reasons in that it
accompanies a return code of '-1', not '0'!  errno will always be set to EFAULT
or EHWPOISON when KVM exits with KVM_EXIT_MEMORY_FAULT, userspace should assume
kvm_run.exit_reason is stale/undefined for all other error numbers.

Signed-off-by: Sagi Shahar <sagis@google.com>
---
 tools/testing/selftests/kvm/lib/kvm_util.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index d024abc5379c..8fb041e51484 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -1742,6 +1742,10 @@ void vcpu_run(struct kvm_vcpu *vcpu)
 {
 	int ret = _vcpu_run(vcpu);
 
+	// Allow this scenario to be handled by the caller.
+	if (ret == -1 && errno == EFAULT)
+		return;
+
 	TEST_ASSERT(!ret, KVM_IOCTL_ERROR(KVM_RUN, ret));
 }
 
-- 
2.43.0.472.g3155946c3a-goog