kernel.git/tools/testing/selftests/kvm, branch linux-6.0.y

KVM: selftests: Fix number of pages for memory slot in memslot_modification_stress_test

2022-11-03T15:00:26Z

[ Upstream commit 05c2224d4b049406b0545a10be05280ff4b8ba0a ] It's required by vm_userspace_mem_region_add() that memory size should be aligned to host page size. However, one guest page is provided by memslot_modification_stress_test. It triggers failure in the scenario of 64KB-page-size-host and 4KB-page-size-guest, as the following messages indicate. # ./memslot_modification_stress_test Testing guest mode: PA-bits:40, VA-bits:48, 4K pages guest physical test memory: [0xffbfff0000, 0xffffff0000) Finished creating vCPUs Started all vCPUs ==== Test Assertion Failure ==== lib/kvm_util.c:824: vm_adjust_num_guest_pages(vm->mode, npages) == npages pid=5712 tid=5712 errno=0 - Success 1 0x0000000000404eeb: vm_userspace_mem_region_add at kvm_util.c:822 2 0x0000000000401a5b: add_remove_memslot at memslot_modification_stress_test.c:82 3 (inlined by) run_test at memslot_modification_stress_test.c:110 4 0x0000000000402417: for_each_guest_mode at guest_modes.c:100 5 0x00000000004016a7: main at memslot_modification_stress_test.c:187 6 0x0000ffffb8cd4383: ?? ??:0 7 0x0000000000401827: _start at :? Number of guest pages is not compatible with the host. Try npages=16 Fix the issue by providing 16 guest pages to the memory slot for this particular combination of 64KB-page-size-host and 4KB-page-size-guest on aarch64. Fixes: ef4c9f4f65462 ("KVM: selftests: Fix 32-bit truncation of vm_get_max_gfn()") Signed-off-by: Gavin Shan Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20221013063020.201856-1-gshan@redhat.com Signed-off-by: Sasha Levin

KVM: selftests: Compare insn opcodes directly in fix_hypercall_test

2022-09-30T10:38:02Z

Directly compare the expected versus observed hypercall instructions when verifying that KVM patched in the native hypercall (FIX_HYPERCALL_INSN quirk enabled). gcc rightly complains that doing a 4-byte memcpy() with an "unsigned char" as the source generates an out-of-bounds accesses. Alternatively, "exp" and "obs" could be declared as 3-byte arrays, but there's no known reason to copy locally instead of comparing directly. In function ‘assert_hypercall_insn’, inlined from ‘guest_main’ at x86_64/fix_hypercall_test.c:91:2: x86_64/fix_hypercall_test.c:63:9: error: array subscript ‘unsigned int[0]’ is partly outside array bounds of ‘unsigned char[1]’ [-Werror=array-bounds] 63 | memcpy(&exp, exp_insn, sizeof(exp)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ x86_64/fix_hypercall_test.c: In function ‘guest_main’: x86_64/fix_hypercall_test.c:42:22: note: object ‘vmx_hypercall_insn’ of size 1 42 | extern unsigned char vmx_hypercall_insn; | ^~~~~~~~~~~~~~~~~~ x86_64/fix_hypercall_test.c:25:22: note: object ‘svm_hypercall_insn’ of size 1 25 | extern unsigned char svm_hypercall_insn; | ^~~~~~~~~~~~~~~~~~ In function ‘assert_hypercall_insn’, inlined from ‘guest_main’ at x86_64/fix_hypercall_test.c:91:2: x86_64/fix_hypercall_test.c:64:9: error: array subscript ‘unsigned int[0]’ is partly outside array bounds of ‘unsigned char[1]’ [-Werror=array-bounds] 64 | memcpy(&obs, obs_insn, sizeof(obs)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ x86_64/fix_hypercall_test.c: In function ‘guest_main’: x86_64/fix_hypercall_test.c:25:22: note: object ‘svm_hypercall_insn’ of size 1 25 | extern unsigned char svm_hypercall_insn; | ^~~~~~~~~~~~~~~~~~ x86_64/fix_hypercall_test.c:42:22: note: object ‘vmx_hypercall_insn’ of size 1 42 | extern unsigned char vmx_hypercall_insn; | ^~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors make: *** [../lib.mk:135: tools/testing/selftests/kvm/x86_64/fix_hypercall_test] Error 1 Fixes: 6c2fa8b20d0c ("selftests: KVM: Test KVM_X86_QUIRK_FIX_HYPERCALL_INSN") Cc: Oliver Upton Signed-off-by: Sean Christopherson Reviewed-by: Oliver Upton Message-Id: <20220928233652.783504-3-seanjc@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Implement memcmp(), memcpy(), and memset() for guest use

2022-09-30T10:38:02Z

Implement memcmp(), memcpy(), and memset() to override the compiler's built-in versions in order to guarantee that the compiler won't generate out-of-line calls to external functions via the PLT. This allows the helpers to be safely used in guest code, as KVM selftests don't support dynamic loading of guest code. Steal the implementations from the kernel's generic versions, sans the optimizations in memcmp() for unaligned accesses. Put the utilities in a separate compilation unit and build with -ffreestanding to fudge around a gcc "feature" where it will optimize memset(), memcpy(), etc... by generating a recursive call. I.e. the compiler optimizes itself into infinite recursion. Alternatively, the individual functions could be tagged with optimize("no-tree-loop-distribute-patterns"), but using "optimize" for anything but debug is discouraged, and Linus NAK'd the use of the flag in the kernel proper[*]. https://lore.kernel.org/lkml/CAHk-=wik-oXnUpfZ6Hw37uLykc-_P0Apyn2XuX-odh-3Nzop8w@mail.gmail.com Cc: Andrew Jones Cc: Anup Patel Cc: Atish Patra Cc: Christian Borntraeger Cc: Janosch Frank Cc: Claudio Imbrenda Signed-off-by: Sean Christopherson Message-Id: <20220928233652.783504-2-seanjc@google.com> Reviewed-by: Andrew Jones Signed-off-by: Paolo Bonzini

KVM: selftests: Gracefully handle empty stack traces

2022-09-30T10:38:00Z

Bail out of test_dump_stack() if the stack trace is empty rather than invoking addr2line with zero addresses. The problem with the latter is that addr2line will block waiting for addresses to be passed in via stdin, e.g. if running a selftest from an interactive terminal. Opportunistically fix up the comment that mentions skipping 3 frames since only 2 are skipped in the code. Cc: Vipin Sharma Cc: Sean Christopherson Signed-off-by: David Matlack Message-Id: <20220922231724.3560211-1-dmatlack@google.com> [Small tweak to keep backtrace() call close to if(). - Paolo] Signed-off-by: Paolo Bonzini

KVM: selftests: replace assertion with warning in access_tracking_perf_test

2022-09-30T10:38:00Z

Page_idle uses {ptep/pmdp}_clear_young_notify which in turn calls the mmu notifier callback ->clear_young(), which purposefully does not flush the TLB. When running the test in a nested guest, point 1. of the test doc header is violated, because KVM TLB is unbounded by size and since no flush is forced, KVM does not update the sptes accessed/idle bits resulting in guest assertion failure. More precisely, only the first ACCESS_WRITE in run_test() actually makes visible changes, because sptes are created and the accessed bit is set to 1 (or idle bit is 0). Then the first mark_memory_idle() passes since access bit is still one, and sets all pages as idle (or not accessed). When the next write is performed, the update is not flushed therefore idle is still 1 and next mark_memory_idle() fails. Signed-off-by: Emanuele Giuseppe Esposito Message-Id: <20220926082923.299554-1-eesposit@redhat.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Skip tests that require EPT when it is not available

2022-09-27T11:58:03Z

Skip selftests that require EPT support in the VM when it is not available. For example, if running on a machine where kvm_intel.ept=N since KVM does not offer EPT support to guests if EPT is not supported on the host. This commit causes vmx_dirty_log_test to be skipped instead of failing on hosts where kvm_intel.ept=N. Signed-off-by: David Matlack Message-Id: <20220926171457.532542-1-dmatlack@google.com> Signed-off-by: Paolo Bonzini

selftests: kvm: Fix a compile error in selftests/kvm/rseq_test.c

2022-09-22T21:02:20Z

The following warning appears when executing: make -C tools/testing/selftests/kvm rseq_test.c: In function ‘main’: rseq_test.c:237:33: warning: implicit declaration of function ‘gettid’; did you mean ‘getgid’? [-Wimplicit-function-declaration] (void *)(unsigned long)gettid()); ^~~~~~ getgid /usr/bin/ld: /tmp/ccr5mMko.o: in function `main': ../kvm/tools/testing/selftests/kvm/rseq_test.c:237: undefined reference to `gettid' collect2: error: ld returned 1 exit status make: *** [../lib.mk:173: ../kvm/tools/testing/selftests/kvm/rseq_test] Error 1 Use the more compatible syscall(SYS_gettid) instead of gettid() to fix it. More subsequent reuse may cause it to be wrapped in a lib file. Signed-off-by: Jinrong Liang Message-Id: <20220802071240.84626-1-cloudliang@tencent.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Fix ambiguous mov in KVM_ASM_SAFE()

2022-08-19T11:38:05Z

Change the mov in KVM_ASM_SAFE() that zeroes @vector to a movb to make it unambiguous. This fixes a build failure with Clang since, unlike the GNU assembler, the LLVM integrated assembler rejects ambiguous X86 instructions that don't have suffixes: In file included from x86_64/hyperv_features.c:13: include/x86_64/processor.h:825:9: error: ambiguous instructions require an explicit suffix (could be 'movb', 'movw', 'movl', or 'movq') return kvm_asm_safe("wrmsr", "a"(val & -1u), "d"(val >> 32), "c"(msr)); ^ include/x86_64/processor.h:802:15: note: expanded from macro 'kvm_asm_safe' asm volatile(KVM_ASM_SAFE(insn) \ ^ include/x86_64/processor.h:788:16: note: expanded from macro 'KVM_ASM_SAFE' "1: " insn "\n\t" \ ^ :5:2: note: instantiated into assembly here mov $0, 15(%rsp) ^ It seems like this change could introduce undesirable behavior in the future, e.g. if someone used a type larger than a u8 for @vector, since KVM_ASM_SAFE() will only zero the bottom byte. I tried changing the type of @vector to an int to see what would happen. GCC failed to compile due to a size mismatch between `movb` and `%eax`. Clang succeeded in compiling, but the generated code looked correct, so perhaps it will not be an issue. That being said it seems like there could be a better solution to this issue that does not assume @vector is a u8. Fixes: 3b23054cd3f5 ("KVM: selftests: Add x86-64 support for exception fixup") Signed-off-by: David Matlack Reviewed-by: Sean Christopherson Message-Id: <20220722234838.2160385-3-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Fix KVM_EXCEPTION_MAGIC build with Clang

2022-08-19T11:38:05Z

Change KVM_EXCEPTION_MAGIC to use the all-caps "ULL", rather than lower case. This fixes a build failure with Clang: In file included from x86_64/hyperv_features.c:13: include/x86_64/processor.h:825:9: error: unexpected token in argument list return kvm_asm_safe("wrmsr", "a"(val & -1u), "d"(val >> 32), "c"(msr)); ^ include/x86_64/processor.h:802:15: note: expanded from macro 'kvm_asm_safe' asm volatile(KVM_ASM_SAFE(insn) \ ^ include/x86_64/processor.h:785:2: note: expanded from macro 'KVM_ASM_SAFE' "mov $" __stringify(KVM_EXCEPTION_MAGIC) ", %%r9\n\t" \ ^ :1:18: note: instantiated into assembly here mov $0xabacadabaull, %r9 ^ Fixes: 3b23054cd3f5 ("KVM: selftests: Add x86-64 support for exception fixup") Signed-off-by: David Matlack Reviewed-by: Sean Christopherson Message-Id: <20220722234838.2160385-2-dmatlack@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Test all possible "invalid" PERF_CAPABILITIES.LBR_FMT vals

2022-08-10T19:08:29Z

Test all possible input values to verify that KVM rejects all values except the exact host value. Due to the LBR format affecting the core functionality of LBRs, KVM can't emulate "other" formats, so even though there are a variety of legal values, KVM should reject anything but an exact host match. Suggested-by: Like Xu Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini