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Subject: Re: [PATCH v5 16/16] x86/tdx: Add cmdline option to force use of
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To:     "Michael S. Tsirkin" <mst@redhat.com>
Cc:     Kuppuswamy Sathyanarayanan 
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From:   Andi Kleen <ak@linux.intel.com>
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> I thought you basically create an OperationRegion of SystemMemory type,
> and off you go. Maybe the OSPM in Linux is clever and protects
> some memory, I wouldn't know.


I investigated this now, and it looks like acpi is using 
ioremap_cache(). We can hook into that and force non sharing. It's 
probably safe to assume that this is not used on real IO devices.

I think there are still some other BIOS mappings that use just plain 
ioremap() though.


-Andi