From 2fe5149bdfbf3c2cdfafd2b5b496252d45ca1f78 Mon Sep 17 00:00:00 2001
From: Ben Gardon <bgardon@google.com>
Date: Tue, 27 Oct 2020 16:37:30 -0700
Subject: [PATCH] KVM: selftests: Remove address rounding in guest code

Rounding the address the guest writes to a host page boundary
will only have an effect if the host page size is larger than the guest
page size, but in that case the guest write would still go to the same
host page. There's no reason to round the address down, so remove the
rounding to simplify the demand paging test.

This series was tested by running the following invocations on an Intel
Skylake machine:
dirty_log_perf_test -b 20m -i 100 -v 64
dirty_log_perf_test -b 20g -i 5 -v 4
dirty_log_perf_test -b 4g -i 5 -v 32
demand_paging_test -b 20m -v 64
demand_paging_test -b 20g -v 4
demand_paging_test -b 4g -v 32
All behaved as expected.

Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20201027233733.1484855-3-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 tools/testing/selftests/kvm/include/perf_test_util.h | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/include/perf_test_util.h b/tools/testing/selftests/kvm/include/perf_test_util.h
index f71f0858a1f29c..838f946700f0c0 100644
--- a/tools/testing/selftests/kvm/include/perf_test_util.h
+++ b/tools/testing/selftests/kvm/include/perf_test_util.h
@@ -72,7 +72,6 @@ static void guest_code(uint32_t vcpu_id)
 	for (i = 0; i < pages; i++) {
 		uint64_t addr = gva + (i * perf_test_args.guest_page_size);
 
-		addr &= ~(perf_test_args.host_page_size - 1);
 		*(uint64_t *)addr = 0x0123456789ABCDEF;
 	}
 
-- 
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