Re: [RFC] xen/x86: allow overlaps with non-RAM regions

[Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>]

On Thu, Apr 24, 2025 at 09:59:00AM +0200, Roger Pau Monné wrote:
> On Wed, Apr 23, 2025 at 04:51:16PM -0700, Lira, Victor M wrote:
> > [    4.570354] Intel(R) 2.5G Ethernet Linux Driver
> > 
> > [    4.579535] Copyright(c) 2018 Intel Corporation.
> > 
> > [    4.588898] sky2: driver version 1.30
> > 
> > (XEN) [   21.644361] d0v3 unable to fixup memory read from 0xfe91000c size 
> > 4: -1
> 
> This fault is unexpected, according to the identity mappings done at
> domain build time:
> 
> d0: identity mappings for IOMMU:
>  [00000000a0, 00000000ff] RW
>  [0000009bff, 0000009fff] RW
>  [00000cabc9, 00000cc14c] RW
>  [00000cc389, 00000cc389] RW
>  [00000cc70a, 00000cd1fe] RW
>  [00000ce000, 00000cffff] RW
>  [00000fd000, 00000fd2ff] RW
> 
> The page at 0xfe910 should be covered by the last range above.  I
> think we have a bug somewhere that unexpectedly unmaps that address.

You sure? 0xfe910 is outside of [00000fd000, 00000fd2ff].

-- 
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab

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