On Mon, 7 Mar 2022 at 22:52, Michael S. Tsirkin <m...@redhat.com> wrote: > > On Mon, Mar 07, 2022 at 05:13:16PM +0000, Peter Maydell wrote: > > Also fails on cross-win64-system: > > > > https://gitlab.com/qemu-project/qemu/-/jobs/2172339938 > > > > ../hw/virtio/virtio.c: In function 'qmp_x_query_virtio_vhost_queue_status': > > ../hw/virtio/virtio.c:4358:30: error: cast from pointer to integer of > > different size [-Werror=pointer-to-int-cast] > > 4358 | status->desc = (uint64_t)(unsigned long)hdev->vqs[queue].desc; > > | ^ > > ../hw/virtio/virtio.c:4359:31: error: cast from pointer to integer of > > different size [-Werror=pointer-to-int-cast] > > 4359 | status->avail = (uint64_t)(unsigned long)hdev->vqs[queue].avail; > > | ^ > > ../hw/virtio/virtio.c:4360:30: error: cast from pointer to integer of > > different size [-Werror=pointer-to-int-cast] > > 4360 | status->used = (uint64_t)(unsigned long)hdev->vqs[queue].used; > > | ^ > > cc1: all warnings being treated as errors
> I dropped these for now but I really question the value of this warning, > as you can see the reason we have the buggy cast to unsigned long > is because someone wanted to shut up the warning on a 32 bit system. > > Now, I could maybe get behind this if it simply warned about a cast that > loses information (cast to a smaller integer) or integer/pointer cast > that does not go through uintptr_t without regard to size. This *is* warning about losing information. On 64-bit Windows pointers are 64 bits but 'long' is 32 bits, so the path pointer -> long -> uint64_t drops the top half of the pointer. thanks -- PMM
