kernel/linux.git/tools/testing/selftests/kvm, branch v5.19

KVM: selftests: Fix target thread to be migrated in rseq_test

2022-07-19T13:03:49+00:00

In rseq_test, there are two threads, which are vCPU thread and migration worker separately. Unfortunately, the test has the wrong PID passed to sched_setaffinity() in the migration worker. It forces migration on the migration worker because zeroed PID represents the calling thread, which is the migration worker itself. It means the vCPU thread is never enforced to migration and it can migrate at any time, which eventually leads to failure as the following logs show. host# uname -r 5.19.0-rc6-gavin+ host# # cat /proc/cpuinfo | grep processor | tail -n 1 processor : 223 host# pwd /home/gavin/sandbox/linux.main/tools/testing/selftests/kvm host# for i in `seq 1 100`; do \ echo "--------> $i"; ./rseq_test; done --------> 1 --------> 2 --------> 3 --------> 4 --------> 5 --------> 6 ==== Test Assertion Failure ==== rseq_test.c:265: rseq_cpu == cpu pid=3925 tid=3925 errno=4 - Interrupted system call 1 0x0000000000401963: main at rseq_test.c:265 (discriminator 2) 2 0x0000ffffb044affb: ?? ??:0 3 0x0000ffffb044b0c7: ?? ??:0 4 0x0000000000401a6f: _start at ??:? rseq CPU = 4, sched CPU = 27 Fix the issue by passing correct parameter, TID of the vCPU thread, to sched_setaffinity() in the migration worker. Fixes: 61e52f1630f5 ("KVM: selftests: Add a test for KVM_RUN+rseq to detect task migration bugs") Suggested-by: Sean Christopherson Signed-off-by: Gavin Shan Reviewed-by: Oliver Upton Message-Id: <20220719020830.3479482-1-gshan@redhat.com> Reviewed-by: Andrew Jones Signed-off-by: Paolo Bonzini

selftests: KVM: Handle compiler optimizations in ucall

2022-06-23T14:26:41+00:00

The selftests, when built with newer versions of clang, is found to have over optimized guests' ucall() function, and eliminating the stores for uc.cmd (perhaps due to no immediate readers). This resulted in the userspace side always reading a value of '0', and causing multiple test failures. As a result, prevent the compiler from optimizing the stores in ucall() with WRITE_ONCE(). Suggested-by: Ricardo Koller Suggested-by: Reiji Watanabe Signed-off-by: Raghavendra Rao Ananta Message-Id: <20220615185706.1099208-1-rananta@google.com> Reviewed-by: Andrew Jones Signed-off-by: Paolo Bonzini

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

2022-06-09T14:52:27+00:00

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

2022-06-09T14:52:27+00:00

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

2022-06-09T14:52:26+00:00

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

2022-06-09T14:52:25+00:00

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

2022-06-09T14:52:25+00:00

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

2022-06-09T14:52:24+00:00

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

2022-06-09T14:52:24+00:00

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

2022-06-09T14:52:23+00:00

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