[PATCH] x86/hvm/dom0: fix PVH initrd and metadata placement

[Xenia Ragiadakou <xenia.ragiadakou@xxxxxxx>]

Given that start < kernel_end and end > kernel_start, the logic that
determines the best placement for dom0 initrd and metadata, does not
take into account the two cases below:
(1) start > kernel_start && end > kernel_end
(2) start < kernel_start && end < kernel_end

In case (1), the evaluation will result in end = kernel_start
i.e. end < start, and will load initrd in the middle of the kernel.
In case (2), the evaluation will result in start = kernel_end
i.e. end < start, and will load initrd at kernel_end, that is out
of the memory region under evaluation.

This patch rephrases the if condition to include the above two cases
without affecting the behaviour for the case where
start < kernel_start && end > kernel_end

Fixes: 73b47eea2104 ('x86/dom0: improve PVH initrd and metadata placement')
Signed-off-by: Xenia Ragiadakou <xenia.ragiadakou@xxxxxxx>
---
 xen/arch/x86/hvm/dom0_build.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/arch/x86/hvm/dom0_build.c b/xen/arch/x86/hvm/dom0_build.c
index c7d47d0d4c..5fc2c12f3a 100644
--- a/xen/arch/x86/hvm/dom0_build.c
+++ b/xen/arch/x86/hvm/dom0_build.c
@@ -518,7 +518,7 @@ static paddr_t __init find_memory(
         if ( end <= kernel_start || start >= kernel_end )
             ; /* No overlap, nothing to do. */
         /* Deal with the kernel already being loaded in the region. */
-        else if ( kernel_start - start > end - kernel_end )
+        else if ( kernel_start + kernel_end > start + end )
             end = kernel_start;
         else
             start = kernel_end;
-- 
2.34.1