linux-kernel - [PATCH gmem 4/5] KVM: selftests: Use dedicated pattern for testing that mem is shared by default

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Date:   Mon, 23 Oct 2023 12:15:31 -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 4/5] KVM: selftests: Use dedicated pattern for testing
 that mem is shared by default

Somewhat arbitrarily use 0xaa as the data pattern when testing that memory
is shared by default.  Inverting the bits of the init pattern (0xcc)
yields 0x33, which just so happens to be the same as pattern #3, i.e. makes
triaging failures on the default check unnecessarily difficult.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 .../selftests/kvm/x86_64/private_mem_conversions_test.c     | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

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 3f6d8d4dbc53..8a2f924fd031 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
@@ -122,13 +122,15 @@ struct {
 
 static void guest_test_explicit_conversion(uint64_t base_gpa, bool do_fallocate)
 {
+	const uint8_t def_p = 0xaa;
 	const uint8_t init_p = 0xcc;
 	uint64_t j;
 	int i;
 
 	/* Memory should be shared by default. */
-	memset((void *)base_gpa, ~init_p, PER_CPU_DATA_SIZE);
-	guest_sync_shared(base_gpa, PER_CPU_DATA_SIZE, (uint8_t)~init_p, init_p);
+	memset((void *)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);
 
 	for (i = 0; i < ARRAY_SIZE(test_ranges); i++) {
-- 
2.42.0.758.gaed0368e0e-goog