The earlyprintk for Xen PV guests utilizes a simple hypercall (console_io) to provide output to Xen emergency console.
Note that the Xen hypervisor should be booted with 'loglevel=all' to output said information. Reported-by: H. Peter Anvin <[email protected]> Signed-off-by: Konrad Rzeszutek Wilk <[email protected]> --- Documentation/kernel-parameters.txt | 3 +++ 1 file changed, 3 insertions(+) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 7660877..73d51ed 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -757,6 +757,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. earlyprintk= [X86,SH,BLACKFIN] earlyprintk=vga + earlyprintk=xen earlyprintk=serial[,ttySn[,baudrate]] earlyprintk=ttySn[,baudrate] earlyprintk=dbgp[debugController#] @@ -774,6 +775,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted. The VGA output is eventually overwritten by the real console. + The xen output can only be used by Xen PV guests. + ekgdboc= [X86,KGDB] Allow early kernel console debugging ekgdboc=kbd -- 1.8.0.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
