Re: [PATCH for-2.6.35] virtio-pci: disable msi at startup

From: Avi Kivity
Date: Wed Jun 23 2010 - 11:17:10 EST


On 06/23/2010 05:43 PM, Michael S. Tsirkin wrote:


If we don't already do so, we
should probably FLR anything that moves when a kexec kernel starts.
Probably only whatever we want to use. But whether this will make it
more, or less robust, is an open question.

I'm thinking of a sound card left on (maybe not something you have in kdump scenarios) or an industrial controller. Those cards have side effects and you want to quiesce them even if you don't know what they are.

Shouldn't a reset be equivalent to power cycling?

If we did this, driver would need to restore registers
such as BAR etc.

We could save/restore the registers we care about.
It seems easier to clear registers we care about.

We know the registers we care about, we don't know the ones we don't. I'm talking about FLRing all cards, not just those you want to use.

It's also too late
now: changing behaviour will break old drivers.

Why? the FLR is triggered by the guest kernel, so all drivers will be aware it was FLRed.

--
error compiling committee.c: too many arguments to function

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