Re: [tip:x86/debug] x86/kdump: No need to disable ioapic/ lapic incrash path

From: Fernando Luis Vázquez Cao
Date: Wed Mar 07 2012 - 05:53:22 EST


On 03/01/2012 08:19 AM, Eric W. Biederman wrote:

Don Zickus<dzickus@xxxxxxxxxx> writes:
It probably is, except I never hacked on idt code before and my assembly
isn't that good. I have been trying to find examples to copy from to give
it a try. So far I was using early_idt_handlers with early_printk to see
if I could capture some printk messages while jumping from the first
kernel to the second kernel (when the other early_idt_handlers would kick
in for the second kernel).

Tips? Better examples?
That is a particularly good example. When I took a quick look earlier
that is the first place we reload the idt in the kernel boot so that is
one of two places that needs to be modified.

Hi Eric, Don

Sorry for chiming in so late.

We run into the same NMI problems and wrote some patches that tackle
the kernel boot side of things. They have been extensively tested using
qemu-kvm and things seem to be working as expected (after receiving an
early NMI the kernel continues without problem; after the iret there is no
stack corruption or register corruption).

I will be replying to this email with the patches.

Thanks,
Fernando
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