From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 2/2] Device assignment: Fix MSI IRQ affinity setting
Date: Thu, 24 May 2012 23:39:08 +0200 (CEST)
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Cc: Richard Weinberger <richard@nod.at>, kvm@vger.kernel.org,
	avi@redhat.com, Marcelo Tosatti <mtosatti@redhat.com>,
	Bjorn Helgaas <bhelgaas@google.com>
To: Alex Williamson <alex.williamson@redhat.com>
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On Thu, 24 May 2012, Alex Williamson wrote:
> On Thu, 2012-05-24 at 18:02 +0100, Richard Weinberger wrote:
> > +            if (address == msi_start + PCI_MSI_DATA_32)
> > +                handle_cfg_write_msi(pci_dev, assigned_dev);
> 
> Why didn't we just use range_covers_byte(address, len, pci_dev->msi_cap
> + PCI_MSI_DATA_32) to start with?  But how does this handle the enable
> bit?

The problem with the current implementation is that it only changes
the routing if the msi entry goes from masked to unmasked state.

Linux does not mask the entries on affinity changes and never did,
neither for MSI nor for MSI-X.

I know it's probably not according to the spec, but we can't fix that
retroactively.

Thanks,

	tglx