From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Jan Beulich" <JBeulich@suse.com>
Subject: Re: [v7][PATCH 06/16] hvmloader/pci: skip reserved
 ranges
Date: Wed, 15 Jul 2015 10:27:02 +0100
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To: Tiejun Chen <tiejun.chen@intel.com>
Cc: Wei Liu <wei.liu2@citrix.com>, Ian Campbell <ian.campbell@citrix.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Andrew Cooper <andrew.cooper3@citrix.com>, Ian Jackson <ian.jackson@eu.citrix.com>, xen-devel@lists.xen.org, Keir Fraser <keir@xen.org>
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>>> On 15.07.15 at 10:59, <tiejun.chen@intel.com> wrote:
> On 2015/7/15 16:34, Jan Beulich wrote:
>>>>> On 15.07.15 at 06:27, <tiejun.chen@intel.com> wrote:
>>> Furthermore, could we have this solution as follows?
>>
>> 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)?
Afaics such a guest would remain permanently unbootable, which
of course is not an option.

Jan