Re: [Xen-devel] [PATCH] xen/hvc-console: Make it work with HVM guests.

From: Julien Grall
Date: Thu Oct 24 2013 - 12:31:06 EST

On 10/24/2013 03:49 PM, Konrad Rzeszutek Wilk wrote:
On Wed, Oct 23, 2013 at 11:08:01PM +0100, Julien Grall wrote:

On 10/23/2013 05:15 PM, Konrad Rzeszutek Wilk wrote:
On Sun, Oct 06, 2013 at 09:52:40PM +0100, Julien Grall wrote:
Actually, I looked closer the code, with the new solution
xen_raw_printk/xen_raw_console_write can't be call on ARM during
early init.

On ARM, xen_domain_type is initialized during a core initcall. So
it's not possible to call the function before.

OK, so won't work and won't harm. That is OK I think.

I use xen_raw_printk every time to debug early code and when someone has an issue with Linux (for instance no log in the console), we advise them to use xen_raw_printk.
It's annoying for every ARM developer to modify ourself the function each time we need it...

I'm sure the solution "move xen call earlier" will come up in few mails, so there was a discussion for swiotlb few weeks ago ( And the final decision was to avoid specific Xen call in arch_setup.

So I think, for now the best solution is to call unconditionally dom0_write_console on ARM (32 and 64 bits).

#ifdef CONFIG_X86
if (xen_domain) {
} else if (...) {

It will avoid to carry non-upstream patch for ARM and point out every time developer to this patch.

Stefano, Ian, any opinion?

Julien Grall
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