kernel/linux.git/tools/testing/selftests/kvm/include/userfaultfd_util.h, branch v6.12.80

Merge tag 'kvm-x86-selftests_utils-6.10' of https://github.com/kvm-x86/linux into HEAD

2024-05-12T07:18:11+00:00

KVM selftests treewide updates for 6.10: - Define _GNU_SOURCE for all selftests to fix a warning that was introduced by a change to kselftest_harness.h late in the 6.9 cycle, and because forcing every test to #define _GNU_SOURCE is painful. - Provide a global psuedo-RNG instance for all tests, so that library code can generate random, but determinstic numbers. - Use the global pRNG to randomly force emulation of select writes from guest code on x86, e.g. to help validate KVM's emulation of locked accesses. - Rename kvm_util_base.h back to kvm_util.h, as the weird layer of indirection was added purely to avoid manually #including ucall_common.h in a handful of locations. - Allocate and initialize x86's GDT, IDT, TSS, segments, and default exception handlers at VM creation, instead of forcing tests to manually trigger the related setup.

KVM: selftests: Define _GNU_SOURCE for all selftests code

2024-04-29T19:49:10+00:00

Define _GNU_SOURCE is the base CFLAGS instead of relying on selftests to manually #define _GNU_SOURCE, which is repetitive and error prone. E.g. kselftest_harness.h requires _GNU_SOURCE for asprintf(), but if a selftest includes kvm_test_harness.h after stdio.h, the include guards result in the effective version of stdio.h consumed by kvm_test_harness.h not defining asprintf(): In file included from x86_64/fix_hypercall_test.c:12: In file included from include/kvm_test_harness.h:11: ../kselftest_harness.h:1169:2: error: call to undeclared function 'asprintf'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 1169 | asprintf(&test_name, "%s%s%s.%s", f->name, | ^ When including the rseq selftest's "library" code, #undef _GNU_SOURCE so that rseq.c controls whether or not it wants to build with _GNU_SOURCE. Reported-by: Muhammad Usama Anjum Acked-by: Claudio Imbrenda Acked-by: Oliver Upton Acked-by: Anup Patel Reviewed-by: Muhammad Usama Anjum Link: https://lore.kernel.org/r/20240423190308.2883084-1-seanjc@google.com Signed-off-by: Sean Christopherson

KVM: selftests: Allow many vCPUs and reader threads per UFFD in demand paging test

2024-04-09T21:28:53+00:00

At the moment, demand_paging_test does not support profiling/testing multiple vCPU threads concurrently faulting on a single uffd because (a) "-u" (run test in userfaultfd mode) creates a uffd for each vCPU's region, so that each uffd services a single vCPU thread. (b) "-u -o" (userfaultfd mode + overlapped vCPU memory accesses) simply doesn't work: the test tries to register the same memory to multiple uffds, causing an error. Add support for many vcpus per uffd by (1) Keeping "-u" behavior unchanged. (2) Making "-u -a" create a single uffd for all of guest memory. (3) Making "-u -o" implicitly pass "-a", solving the problem in (b). In cases (2) and (3) all vCPU threads fault on a single uffd. With potentially multiple vCPUs per UFFD, it makes sense to allow configuring the number of reader threads per UFFD as well: add the "-r" flag to do so. Signed-off-by: Anish Moorthy Acked-by: James Houghton Link: https://lore.kernel.org/r/20240215235405.368539-12-amoorthy@google.com [sean: fix kernel style violations, use calloc() for arrays] Signed-off-by: Sean Christopherson

KVM: selftests: Add a userfaultfd library

2022-11-10T19:10:27+00:00

Move the generic userfaultfd code out of demand_paging_test.c into a common library, userfaultfd_util. This library consists of a setup and a stop function. The setup function starts a thread for handling page faults using the handler callback function. This setup returns a uffd_desc object which is then used in the stop function (to wait and destroy the threads). Reviewed-by: Oliver Upton Reviewed-by: Ben Gardon Signed-off-by: Ricardo Koller Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20221017195834.2295901-2-ricarkol@google.com