linux-kernel - [PATCH gmem 5/5] KVM: selftests: Verify default pattern was written in private mem conversion

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Date:   Mon, 23 Oct 2023 12:15:32 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Michael Roth <michael.roth@....com>
Subject: [PATCH gmem 5/5] KVM: selftests: Verify default pattern was written
 in private mem conversion

Add a super paranoid sanity check in the private mem conversion test to
verify that the initial "default" pattern was actually written.  The check
doesn't add meaningful test coverage, the goal is mostly to aid in debug
if something goes sideways, e.g. to give the user confidence that the
writes didn't somehow get dropped entirely.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 .../testing/selftests/kvm/x86_64/private_mem_conversions_test.c  | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/kvm/x86_64/private_mem_conversions_test.c b/tools/testing/selftests/kvm/x86_64/private_mem_conversions_test.c
index 8a2f924fd031..91f343609e18 100644
--- a/tools/testing/selftests/kvm/x86_64/private_mem_conversions_test.c
+++ b/tools/testing/selftests/kvm/x86_64/private_mem_conversions_test.c
@@ -129,6 +129,7 @@ static void guest_test_explicit_conversion(uint64_t base_gpa, bool do_fallocate)
 
 	/* Memory should be shared by default. */
 	memset((void *)base_gpa, def_p, PER_CPU_DATA_SIZE);
+	memcmp_g(base_gpa, def_p, PER_CPU_DATA_SIZE);
 	guest_sync_shared(base_gpa, PER_CPU_DATA_SIZE, def_p, init_p);
 
 	memcmp_g(base_gpa, init_p, PER_CPU_DATA_SIZE);
-- 
2.42.0.758.gaed0368e0e-goog