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This test serves as a performance tester and a bug reproducer for kvm page table code (GPA->HPA mappings), so it gives guidance for people trying to make some improvement for kvm. The function guest_code() can cover the conditions where a single vcpu or multiple vcpus access guest pages within the same memory region, in three VM stages(before dirty logging, during dirty logging, after dirty logging). Besides, the backing src memory type(ANONYMOUS/THP/HUGETLB) of the tested memory region can be specified by users, which means normal page mappings or block mappings can be chosen by users to be created in the test. If ANONYMOUS memory is specified, kvm will create normal page mappings for the tested memory region before dirty logging, and update attributes of the page mappings from RO to RW during dirty logging. If THP/HUGETLB memory is specified, kvm will create block mappings for the tested memory region before dirty logging, and split the blcok mappings into normal page mappings during dirty logging, and coalesce the page mappings back into block mappings after dirty logging is stopped. So in summary, as a performance tester, this test can present the performance of kvm creating/updating normal page mappings, or the performance of kvm creating/splitting/recovering block mappings, through execution time. When we need to coalesce the page mappings back to block mappings after dirty logging is stopped, we have to firstly invalidate *all* the TLB entries for the page mappings right before installation of the block entry, because a TLB conflict abort error could occur if we can't invalidate the TLB entries fully. We have hit this TLB conflict twice on aarch64 software implementation and fixed it. As this test can imulate process from dirty logging enabled to dirty logging stopped of a VM with block mappings, so it can also reproduce this TLB conflict abort due to inadequate TLB invalidation when coalescing tables. Signed-off-by: Yanan Wang <wangyanan55@huawei.com> Reviewed-by: Ben Gardon <bgardon@google.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Message-Id: <20210330080856.14940-11-wangyanan55@huawei.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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| fault-injection | ||
| ktest | ||
| kunit | ||
| nvdimm | ||
| radix-tree | ||
| scatterlist | ||
| selftests | ||
| vsock | ||