From 5132411985e14b8dda69173abee8ea9ba942698f Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 14 Dec 2018 12:29:43 +0100 Subject: [PATCH] kvm: selftests: ucall: improve ucall placement in memory, fix unsigned comparison Based on a patch by Andrew Jones. Reported-by: Dan Carpenter Signed-off-by: Paolo Bonzini --- tools/testing/selftests/kvm/lib/ucall.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/tools/testing/selftests/kvm/lib/ucall.c b/tools/testing/selftests/kvm/lib/ucall.c index 4777f9bb5194..694bc2eaa63e 100644 --- a/tools/testing/selftests/kvm/lib/ucall.c +++ b/tools/testing/selftests/kvm/lib/ucall.c @@ -34,7 +34,7 @@ void ucall_init(struct kvm_vm *vm, ucall_type_t type, void *arg) return; if (type == UCALL_MMIO) { - vm_paddr_t gpa, start, end, step; + vm_paddr_t gpa, start, end, step, offset; bool ret; if (arg) { @@ -53,17 +53,15 @@ void ucall_init(struct kvm_vm *vm, ucall_type_t type, void *arg) * KVM_EXIT_MMIO. Well, at least that's how it works for AArch64. * Here we start with a guess that the addresses around two * thirds of the VA space are unmapped and then work both down - * and up from there in 1/6 VA space sized steps. + * and up from there in 1/12 VA space sized steps. */ start = 1ul << (vm->va_bits * 2 / 3); end = 1ul << vm->va_bits; - step = 1ul << (vm->va_bits / 6); - for (gpa = start; gpa >= 0; gpa -= step) { - if (ucall_mmio_init(vm, gpa & ~(vm->page_size - 1))) + step = 1ul << (vm->va_bits / 12); + for (offset = 0; offset < end - start; offset += step) { + if (ucall_mmio_init(vm, (gpa - offset) & ~(vm->page_size - 1))) return; - } - for (gpa = start + step; gpa < end; gpa += step) { - if (ucall_mmio_init(vm, gpa & ~(vm->page_size - 1))) + if (ucall_mmio_init(vm, (gpa + offset) & ~(vm->page_size - 1))) return; } TEST_ASSERT(false, "Can't find a ucall mmio address"); -- 2.30.2