On Fri, Apr 10, 2020 at 04:17:01PM -0700, Sean Christopherson wrote: > Add variants of GUEST_ASSERT to pass values back to the host, e.g. to > help debug/understand a failure when the the cause of the assert isn't > necessarily binary. > > It'd probably be possible to auto-calculate the number of arguments and > just have a single GUEST_ASSERT, but there are a limited number of > variants and silently eating arguments could lead to subtle code bugs. > > Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> > --- > .../testing/selftests/kvm/include/kvm_util.h | 25 +++++++++++++++---- > 1 file changed, 20 insertions(+), 5 deletions(-) > > diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h > index d4c3e4d9cd92..e38d91bd8ec1 100644 > --- a/tools/testing/selftests/kvm/include/kvm_util.h > +++ b/tools/testing/selftests/kvm/include/kvm_util.h > @@ -313,11 +313,26 @@ uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc); > > #define GUEST_SYNC(stage) ucall(UCALL_SYNC, 2, "hello", stage) > #define GUEST_DONE() ucall(UCALL_DONE, 0) > -#define GUEST_ASSERT(_condition) do { \ > - if (!(_condition)) \ > - ucall(UCALL_ABORT, 2, \ > - "Failed guest assert: " \ > - #_condition, __LINE__); \ > +#define __GUEST_ASSERT(_condition, _nargs, _args...) do { \ > + if (!(_condition)) \ > + ucall(UCALL_ABORT, 2 + _nargs, \ Need () around _nargs > + "Failed guest assert: " \ > + #_condition, __LINE__, _args); \ > } while (0) We can free up another arg and add __FILE__. Something like the following (untested): #include "linux/stringify.h" #define __GUEST_ASSERT(_condition, _nargs, _args...) do { \ if (!(_condition)) \ ucall(UCALL_ABORT, (_nargs) + 1, \ "Failed guest assert: " \ #_condition " at " __FILE__ ":" __stringify(__LINE__), _args); \ } while (0) > > +#define GUEST_ASSERT(_condition) \ > + __GUEST_ASSERT((_condition), 0, 0) > + > +#define GUEST_ASSERT_1(_condition, arg1) \ > + __GUEST_ASSERT((_condition), 1, (arg1)) > + > +#define GUEST_ASSERT_2(_condition, arg1, arg2) \ > + __GUEST_ASSERT((_condition), 2, (arg1), (arg2)) > + > +#define GUEST_ASSERT_3(_condition, arg1, arg2, arg3) \ > + __GUEST_ASSERT((_condition), 3, (arg1), (arg2), (arg3)) > + > +#define GUEST_ASSERT_4(_condition, arg1, arg2, arg3, arg4) \ > + __GUEST_ASSERT((_condition), 4, (arg1), (arg2), (arg3), (arg4)) > + nit: don't need the () around any of the macro params above > #endif /* SELFTEST_KVM_UTIL_H */ > -- > 2.26.0 > We could instead add test specific ucalls. To do so, we should first add UCALL_TEST_SPECIFIC = 32 to the ucall enum, and then tests could extend it enum { MY_UCALL_1 = UCALL_TEST_SPECIFIC, MY_UCALL_2, }; With appropriately named test specific ucalls it may allow for clearer code. At least GUEST_ASSERT_<N> wouldn't take on new meanings for each test. Thanks, drew