Re: [Qemu-devel] [PATCH 1/3] libqos: Remove PCI assumptions in virtio driver

[Stefan Hajnoczi]

On Fri, Oct 03, 2014 at 01:53:13PM +0200, Marc Marí wrote:
> El Thu, 2 Oct 2014 13:02:25 +0100
> Stefan Hajnoczi <address@hidden> escribió:
> > On Thu, Sep 04, 2014 at 06:24:37PM +0200, Marc Marí wrote:
> > > @@ -60,25 +60,25 @@ static void
> > > qvirtio_pci_assign_device(QVirtioDevice *d, void *data) *vpcidev =
> > > (QVirtioPCIDevice *)d; }
> > >  
> > > -static uint8_t qvirtio_pci_config_readb(QVirtioDevice *d, void
> > > *addr) +static uint8_t qvirtio_pci_config_readb(QVirtioDevice *d,
> > > uint64_t addr) {
> > >      QVirtioPCIDevice *dev = (QVirtioPCIDevice *)d;
> > > -    return qpci_io_readb(dev->pdev, addr);
> > > +    return qpci_io_readb(dev->pdev, (void *)addr);
> > 
> > You do not need casts in C for void* to any pointer type or any
> > pointer type to void*.  Please drop them.
> 
> addr is of type uint64_t, not a pointer. So if there's no cast it will
> fail to compile (expected ‘void *’ but argument is of type ‘uint64_t’)

Hmm...on 32-bit hosts that causes an error:

a.c:7:17: warning: cast to pointer from integer of different size 
[-Wint-to-pointer-cast]
  printf("%p\n", (void*)u64);

You need to cast to uintptr_t first:

  (void*)(uintptr_t)addr

This assumes that PCI IO Space addresses are 32-bit when running 32-bit
hosts.  Not sure whether or not that's true, but at least for x86 it
works since the legacy PIO address space is 16-bit.

Stefan

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