Re: [Xen-devel] [v7][PATCH 06/16] hvmloader/pci: skip reserved ranges

["Chen, Tiejun" <tiejun.chen@xxxxxxxxx>]

> > > Yet more special casing code you want to add. I said no to this
> > > model, and unless you can address the issue _without_ adding
> > > a lot of special casing code, the answer will remain no (subject
> > What about this?
> >
> > @@ -301,6 +301,19 @@ void pci_setup(void)
> >                pci_mem_start <<= 1;
> >        }
> >
> > +    for ( i = 0; i < memory_map.nr_map ; i++ )
> > +    {
> > +        uint64_t reserved_start, reserved_size;
> > +        reserved_start = memory_map.map[i].addr;
> > +        reserved_size = memory_map.map[i].size;
> > +        if ( check_overlap(pci_mem_start, pci_mem_end - pci_mem_start,
> > +                           reserved_start, reserved_size) )
> > +        {
> > +            printf("Reserved device memory conflicts current PCI memory.\n");
> > +            BUG();
> > +        }
> > +    }
> So what would the cure be if someone ran into this BUG() (other
> than removing the device associated with the conflicting RMRR)?
Maybe I  can move this chunk of codes downward those actual allocation 
to check if RDM conflicts with the final allocation, and then just 
disable those associated devices by writing PCI_COMMAND without BUG() 
like this draft code,
    /* If pci bars conflict with RDM we need to disable this pci device. */
    for ( devfn = 0; devfn < 256; devfn++ )
    {
        bar_sz = pci_readl(devfn, bar_reg);
        bar_data = pci_readl(devfn, bar_reg);
        bar_data_upper = pci_readl(devfn, bar_reg + 4);
        /* Until here we don't conflict high memory. */
        if ( bar_data_upper )
            continue;

        for ( i = 0; i < memory_map.nr_map ; i++ )
        {
            uint64_t reserved_start, reserved_size;
            reserved_start = memory_map.map[i].addr;
            reserved_size = memory_map.map[i].size;
            if ( check_overlap(bar_data & ~(bar_sz - 1), bar_sz,
                               reserved_start, reserved_size) )
            {
                printf("Reserved device memory conflicts with this pci 
bar,"
                       " so just disable this device.\n");
                /* Now disable this device */
                cmd = pci_readw(devfn, PCI_COMMAND);
                pci_writew(devfn, PCI_COMMAND, ~cmd);
            }
        }
    }

If this is still not fine to you, look I have to raise a request to 
co-maintainers since its hard to step next in practice.
Hi all guys, what about your idea?

Thanks
Tiejun

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel