Re: [PATCH] PCI MSI: allow alignment restrictions on vector allocation

From: Thomas Gleixner
Date: Mon Oct 02 2017 - 12:19:47 EST

On Mon, 2 Oct 2017, Thomas Gleixner wrote:
> On Mon, 2 Oct 2017, Daniel Drake wrote:
> 2) The affinity setting of straight MSI interrupts (w/o remapping) on x86
> requires to make the affinity change from the interrupt context of the
> current active vector in order not to lose interrupts or worst case
> getting into a stale state.
> That works for single vectors, but trying to move all vectors in one
> go is more or less impossible, as there is no reliable way to
> determine that none of the other vectors is on flight.
> There might be some 'workarounds' for that, but I rather avoid that
> unless we get an official documented one from Intel/AMD.

Thinking more about it. That might be actually a non issue for MSI, but we
have that modus operandi in the current code and we need to address that
first before even thinking about multi MSI support.