linux-dev/tools/testing/selftests/kvm, branch linus/master

KVM: selftests: Restrict test region to 48-bit physical addresses when using nested

2022-06-09T14:52:27Z

The selftests nested code only supports 4-level paging at the moment. This means it cannot map nested guest physical addresses with more than 48 bits. Allow perf_test_util nested mode to work on hosts with more than 48 physical addresses by restricting the guest test region to 48-bits. While here, opportunistically fix an off-by-one error when dealing with vm_get_max_gfn(). perf_test_util.c was treating this as the maximum number of GFNs, rather than the maximum allowed GFN. This didn't result in any correctness issues, but it did end up shifting the test region down slightly when using huge pages. Suggested-by: Sean Christopherson Signed-off-by: David Matlack Message-Id: <20220520233249.3776001-12-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Add option to run dirty_log_perf_test vCPUs in L2

2022-06-09T14:52:27Z

Add an option to dirty_log_perf_test that configures the vCPUs to run in L2 instead of L1. This makes it possible to benchmark the dirty logging performance of nested virtualization, which is particularly interesting because KVM must shadow L1's EPT/NPT tables. For now this support only works on x86_64 CPUs with VMX. Otherwise passing -n results in the test being skipped. Signed-off-by: David Matlack Message-Id: <20220520233249.3776001-11-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Clean up LIBKVM files in Makefile

2022-06-09T14:52:26Z

Break up the long lines for LIBKVM and alphabetize each architecture. This makes reading the Makefile easier, and will make reading diffs to LIBKVM easier. No functional change intended. Reviewed-by: Peter Xu Signed-off-by: David Matlack Message-Id: <20220520233249.3776001-10-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Link selftests directly with lib object files

2022-06-09T14:52:25Z

The linker does obey strong/weak symbols when linking static libraries, it simply resolves an undefined symbol to the first-encountered symbol. This means that defining __weak arch-generic functions and then defining arch-specific strong functions to override them in libkvm will not always work. More specifically, if we have: lib/generic.c: void __weak foo(void) { pr_info("weak\n"); } void bar(void) { foo(); } lib/x86_64/arch.c: void foo(void) { pr_info("strong\n"); } And a selftest that calls bar(), it will print "weak". Now if you make generic.o explicitly depend on arch.o (e.g. add function to arch.c that is called directly from generic.c) it will print "strong". In other words, it seems that the linker is free to throw out arch.o when linking because generic.o does not explicitly depend on it, which causes the linker to lose the strong symbol. One solution is to link libkvm.a with --whole-archive so that the linker doesn't throw away object files it thinks are unnecessary. However that is a bit difficult to plumb since we are using the common selftests makefile rules. An easier solution is to drop libkvm.a just link selftests with all the .o files that were originally in libkvm.a. Reviewed-by: Peter Xu Signed-off-by: David Matlack Message-Id: <20220520233249.3776001-9-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Drop unnecessary rule for STATIC_LIBS

2022-06-09T14:52:25Z

Drop the "all: $(STATIC_LIBS)" rule. The KVM selftests already depend on $(STATIC_LIBS), so there is no reason to have an extra "all" rule. Suggested-by: Peter Xu Signed-off-by: David Matlack Message-Id: <20220520233249.3776001-8-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Add a helper to check EPT/VPID capabilities

2022-06-09T14:52:24Z

Create a small helper function to check if a given EPT/VPID capability is supported. This will be re-used in a follow-up commit to check for 1G page support. No functional change intended. Reviewed-by: Peter Xu Signed-off-by: David Matlack Message-Id: <20220520233249.3776001-7-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Move VMX_EPT_VPID_CAP_AD_BITS to vmx.h

2022-06-09T14:52:24Z

This is a VMX-related macro so move it to vmx.h. While here, open code the mask like the rest of the VMX bitmask macros. No functional change intended. Reviewed-by: Peter Xu Signed-off-by: David Matlack Message-Id: <20220520233249.3776001-6-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Refactor nested_map() to specify target level

2022-06-09T14:52:23Z

Refactor nested_map() to specify that it explicityl wants 4K mappings (the existing behavior) and push the implementation down into __nested_map(), which can be used in subsequent commits to create huge page mappings. No function change intended. Reviewed-by: Peter Xu Signed-off-by: David Matlack Message-Id: <20220520233249.3776001-5-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Drop stale function parameter comment for nested_map()

2022-06-09T14:52:23Z

nested_map() does not take a parameter named eptp_memslot. Drop the comment referring to it. Reviewed-by: Peter Xu Signed-off-by: David Matlack Message-Id: <20220520233249.3776001-4-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Add option to create 2M and 1G EPT mappings

2022-06-09T14:52:22Z

The current EPT mapping code in the selftests only supports mapping 4K pages. This commit extends that support with an option to map at 2M or 1G. This will be used in a future commit to create large page mappings to test eager page splitting. No functional change intended. Signed-off-by: David Matlack Message-Id: <20220520233249.3776001-3-dmatlack@google.com> Signed-off-by: Paolo Bonzini