Re: [Xen-devel] [PATCH V2 2/3] xen: eliminate scalability issues from initrd handling

From: Juergen Gross
Date: Wed Sep 17 2014 - 10:01:41 EST


On 09/17/2014 03:45 PM, David Vrabel wrote:
On 17/09/14 05:12, Juergen Gross wrote:
Size restrictions native kernels wouldn't have resulted from the initrd
getting mapped into the initial mapping. The kernel doesn't really need
the initrd to be mapped, so use infrastructure available in Xen to avoid
the mapping and hence the restriction.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
arch/x86/xen/enlighten.c | 11 +++++++++--
arch/x86/xen/xen-head.S | 1 +
2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index c0cb11f..8fd075f 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1519,6 +1519,7 @@ static void __init xen_pvh_early_guest_init(void)
asmlinkage __visible void __init xen_start_kernel(void)
{
struct physdev_set_iopl set_iopl;
+ unsigned long initrd_start = 0;
int rc;

if (!xen_start_info)
@@ -1667,10 +1668,16 @@ asmlinkage __visible void __init xen_start_kernel(void)
new_cpu_data.x86_capability[0] = cpuid_edx(1);
#endif

+ if (xen_start_info->mod_start)
+ initrd_start = __pa(xen_start_info->mod_start);
+#ifdef CONFIG_BLK_DEV_INITRD
+ if (xen_start_info->flags & SIF_MOD_START_PFN)
+ initrd_start = PFN_PHYS(xen_start_info->mod_start);
+#endif

Why the #ifdef?

I'll fix this up to be:

if (xen_start_info->mod_start) {
if (xen_start_info->flags & SIF_MOD_START_PFN)
initrd_start = PFN_PHYS_(xen_start_info->mod_start);
else
initrd_start = __pa(xen_start_info->mod_start);
}

Unless you object.

Yeah, you are right. This seems to be okay.


Juergen

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