From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH v4 11/15] pci: Add pci_iomap_shared{,_range}
Date: Fri, 24 Sep 2021 15:43:40 -0700
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>, "Kuppuswamy, Sathyanarayanan" <sathyanarayanan.kuppuswamy@linux.intel.com>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, Peter Zijlstra <peterz@infradead.org>, Andy Lutomirski <luto@kernel.org>, Bjorn Helgaas <bhelgaas@google.com>, Richard Henderson <rth@twiddle.net>, Thomas Bogendoerfer <tsbogend@alpha.franken.de>, James E J Bottomley <James.Bottomley@hansenpartnership.com>, Helge Deller <deller@gmx.de>, "David S . Miller" <davem@davemloft.net>, Arnd Bergmann <arnd@arndb.de>, Jonathan Corbet <corbet@lwn.net>, Peter H Anvin <hpa@zytor.com>, Dave Hansen <dave.hansen@intel.com>, Tony Luck <tony.luck@intel.com>, Kirill Shutemov <kirill.shutemov@lin>


>> Hmm, yes that's true. I guess we can make it default to opt-in for
>> pci_iomap.
>>
>> It only really matters for device less ioremaps.
> OK. And same thing for other things with device, such as
> devm_platform_ioremap_resource.
> If we agree on all that, this will basically remove virtio
> changes from the picture ;)

Hi we revisited this now. One problem with removing the ioremap opt-in 
is that it's still possible for drivers to get at devices without going 
through probe. For example they can walk the PCI device list. Some 
drivers do that for various reasons. So if we remove the opt-in we would 
need to audit and possibly fix all that, which would be potentially a 
lot of churn. That's why I think it's better to keep the opt-in.


-Andi