Re: [Qemu-devel] [PATCH v8 12/17] pci: Convert msi_init() to Error and fix callers to check it

[Cao jin]

On 06/13/2016 06:16 PM, Marcel Apfelbaum wrote:
> On 06/10/2016 12:54 PM, Cao jin wrote:

> > diff --git a/hw/net/e1000e.c b/hw/net/e1000e.c
> > index 692283f..a06d184 100644
> > --- a/hw/net/e1000e.c
> > +++ b/hw/net/e1000e.c
> > @@ -268,13 +268,9 @@ e1000e_init_msi(E1000EState *s)
> >   {
> >       int res;
> >
> > -    res = msi_init(PCI_DEVICE(s),
> > -                   0xD0,   /* MSI capability offset              */
> > -                   1,      /* MAC MSI interrupts                 */
> > -                   true,   /* 64-bit message addresses supported */
> > -                   false); /* Per vector mask supported          */
> > +    res = msi_init(PCI_DEVICE(s), 0xD0, 1, true, false, NULL);
>
> Why did you chose to remove author's comments?

Because msi_init() has its function comments now, which is the same is 
the author`s comments, I guess author add these comments because 
function has no comment before, remove comments also is to save screen 
space:)

some macros of some devices is also unnecessary I think, because we have 
comments of msi_init().

> > +
> > +#define VMXNET3_USE_64BIT         (true)
> > +#define VMXNET3_PER_VECTOR_MASK   (false)
> > +

like these macros, but it does't take too much space as above one I 
feel, so I didn't touch them.

> > @@ -56,14 +57,17 @@ static int xio3130_upstream_initfn(PCIDevice *d)
> >   {
> >       PCIEPort *p = PCIE_PORT(d);
> >       int rc;
> > +    Error *err = NULL;
> >
> >       pci_bridge_initfn(d, TYPE_PCIE_BUS);
> >       pcie_port_init_reg(d);
> >
> >       rc = msi_init(d, XIO3130_MSI_OFFSET, XIO3130_MSI_NR_VECTOR,
> >                     XIO3130_MSI_SUPPORTED_FLAGS & PCI_MSI_FLAGS_64BIT,
> > -                  XIO3130_MSI_SUPPORTED_FLAGS & PCI_MSI_FLAGS_MASKBIT);
> > +                  XIO3130_MSI_SUPPORTED_FLAGS &
> > PCI_MSI_FLAGS_MASKBIT, &err);
> >       if (rc < 0) {
> > +        assert(rc == -ENOTSUP);
> > +        error_report_err(err);
>
> Hi Jin, Markus
>
> It looks a little weird to me to check for negative error code
> and then assert for a specific error as the only "valid error".
> Maybe we should assert inside msi_init to leave the callers "clean"?
Hi Marcel,

I think it is because: except assigned device(vfio), the emulated pci 
devices won`t have config space overlapped(-EINVAL), unless programming 
error.

If implemented as you said, I guess there need a judgement (if..else..) 
to check if current device is assigned in msi_init(), or else assert the 
error

> I am well aware a lot of time was spent for this series, but I just
> spotted it and I want to be sure we are doing it right.
>
> Thanks,
> Marcel

--
Yours Sincerely,

Cao jin