Xen devel - Mar 2013 - [PATCH 1/2] xen: Improve calculation of beginning of virtual address space

Xen changeset 26447 (x86: re-introduce map_domain_page() et al) once again
altered virtual address space. Current algorithm calculating its start could
not cope with that change. New version establishes this value on the base of
image start address and is more generic.

Signed-off-by: Daniel Kiper
<daniel.kiper-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>

diff -Npru crash-6.1.4.orig/xen_hyper.c crash-6.1.4/xen_hyper.c
--- crash-6.1.4.orig/xen_hyper.c	2013-02-14 21:38:54.000000000 +0100
+++ crash-6.1.4/xen_hyper.c	2013-03-15 13:11:16.595713662 +0100
@@ -43,10 +43,14 @@ xen_hyper_init(void)
 #endif
 
 #ifdef X86_64
-	if (xen_major_version() >= 4)
-		xht->xen_virt_start = 0xffff82c480000000;
-	else
-		xht->xen_virt_start = 0xffff828c80000000;
+	xht->xen_virt_start = symbol_value("start");
+
+	/*
+	 * Xen virtual mapping is aligned to 1 GiB boundary.
+	 * Image starts no more than 1 GiB below
+	 * beginning of virtual address space.
+	 */
+	xht->xen_virt_start &= 0xffffffffc0000000;
 #endif
 
 	if (machine_type("X86_64") &&

On Fri, Mar 15, 2013 at 04:09:21PM +0100, Daniel Kiper
wrote:
> Xen changeset 26447 (x86: re-introduce map_domain_page() et al) once again
> altered virtual address space. Current algorithm calculating its start
could
> not cope with that change. New version establishes this value on the base
of
> image start address and is more generic.
And it works with the older (3.4) hypervisors binary
image?
> 
> Signed-off-by: Daniel Kiper
<daniel.kiper-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
> 
> diff -Npru crash-6.1.4.orig/xen_hyper.c crash-6.1.4/xen_hyper.c
> --- crash-6.1.4.orig/xen_hyper.c	2013-02-14 21:38:54.000000000 +0100
> +++ crash-6.1.4/xen_hyper.c	2013-03-15 13:11:16.595713662 +0100
> @@ -43,10 +43,14 @@ xen_hyper_init(void)
>  #endif
>  
>  #ifdef X86_64
> -	if (xen_major_version() >= 4)
> -		xht->xen_virt_start = 0xffff82c480000000;
> -	else
> -		xht->xen_virt_start = 0xffff828c80000000;
> +	xht->xen_virt_start = symbol_value("start");
> +
> +	/*
> +	 * Xen virtual mapping is aligned to 1 GiB boundary.
> +	 * Image starts no more than 1 GiB below
> +	 * beginning of virtual address space.
> +	 */
> +	xht->xen_virt_start &= 0xffffffffc0000000;
>  #endif
>  
>  	if (machine_type("X86_64") &&
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel-GuqFBffKawuEi8DpZVb4nw@public.gmane.org
> http://lists.xen.org/xen-devel
>

On Fri, Mar 15, 2013 at 12:56:36PM -0400, Konrad Rzeszutek Wilk
wrote:
> On Fri, Mar 15, 2013 at 04:09:21PM +0100, Daniel Kiper wrote:
> > Xen changeset 26447 (x86: re-introduce map_domain_page() et al) once
again
> > altered virtual address space. Current algorithm calculating its start
could
> > not cope with that change. New version establishes this value on the
base of
> > image start address and is more generic.
>
> And it works with the older (3.4) hypervisors binary image?
It works without any issue.

Daniel