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KVM: selftests: Remove address rounding in guest code

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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>
This commit is contained in:
Ben Gardon 2020-10-27 16:37:30 -07:00 committed by Paolo Bonzini
parent 4b5d12b0e2
commit 2fe5149bdf
1 changed files with 0 additions and 1 deletions
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1
tools/testing/selftests/kvm/include/perf_test_util.h
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@ -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;
}