Re: [Qemu-devel] [PULL 05/22] virtio-pmem: add virtio device

[Peter Maydell]

On Tue, 2 Jul 2019 at 16:07, Michael S. Tsirkin <address@hidden> wrote:
>
> From: Pankaj Gupta <address@hidden>
>
> This is the implementation of virtio-pmem device. Support will require
> machine changes for the architectures that will support it, so it will
> not yet be compiled. It can be unlocked with VIRTIO_PMEM_SUPPORTED per
> machine and disabled globally via VIRTIO_PMEM.
>
> We cannot use the "addr" property as that is already used e.g. for
> virtio-pci/pci devices. And we will have e.g. virtio-pmem-pci as a proxy.
> So we have to choose a different one (unfortunately). "memaddr" it is.
> That name should ideally be used by all other virtio-* based memory
> devices in the future.
>     -device virtio-pmem-pci,id=p0,bus=bux0,addr=0x01,memaddr=0x1000000...
>
> Acked-by: Markus Armbruster <address@hidden>
> [ QAPI bits ]
> Signed-off-by: Pankaj Gupta <address@hidden>
> [ MemoryDevice/MemoryRegion changes, cleanups, addr property "memaddr",
>   split up patches, unplug handler ]
> Signed-off-by: David Hildenbrand <address@hidden>
> Message-Id: <address@hidden>
> Reviewed-by: Michael S. Tsirkin <address@hidden>
> Signed-off-by: Michael S. Tsirkin <address@hidden>

> +static void virtio_pmem_fill_device_info(const VirtIOPMEM *pmem,
> +                                         VirtioPMEMDeviceInfo *vi)
> +{
> +    vi->memaddr = pmem->start;
> +    vi->size = pmem->memdev ? memory_region_size(&pmem->memdev->mr) : 0;
> +    vi->memdev = object_get_canonical_path(OBJECT(pmem->memdev));

Hi; Coverity points out (CID 1403009) that when we're assigning
vi->size we handle the "pmem->memdev is NULL" case; but we then
pass it into object_get_canonical_path(), which unconditionally
dereferences it and will crash if it is NULL. If this pointer
can be NULL then we need to do something else here.

> +}

thanks
-- PMM