@@ -515,16 +515,23 @@ static paddr_t __init find_memory(
ASSERT(IS_ALIGNED(start, PAGE_SIZE) && IS_ALIGNED(end, PAGE_SIZE));
+ /*
+ * NB: Even better would be to use rangesets to determine a suitable
+ * range, in particular in case a kernel requests multiple heavily
+ * discontiguous regions (which right now we fold all into one big
+ * region).
+ */
if ( end <= kernel_start || start >= kernel_end )
- ; /* No overlap, nothing to do. */
+ {
+ /* No overlap, just check whether the region is large enough. */
+ if ( end - start >= size )
+ return start;
+ }
/* Deal with the kernel already being loaded in the region. */
- else if ( kernel_start - start > end - kernel_end )
- end = kernel_start;
- else
- start = kernel_end;
-
- if ( end - start >= size )
+ else if ( kernel_start > start && kernel_start - start >= size )
return start;
+ else if ( kernel_end < end && end - kernel_end >= size )
+ return kernel_end;
}
return INVALID_PADDR;
Zephyr image consists of multiple non-contiguous load segments that reside in different RAM regions. For instance: ELF: phdr: paddr=0x1000 memsz=0x8000 ELF: phdr: paddr=0x100000 memsz=0x28a90 ELF: phdr: paddr=0x128aa0 memsz=0x7560 ELF: memory: 0x1000 -> 0x130000 However, the logic that determines the best placement for dom0 initrd and metadata, assumes that the image is fully contained in a single RAM region, not taking into account the cases where: (1) start > kernel_start && end > kernel_end (2) start < kernel_start && end < kernel_end (3) 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. In case (3), the evaluation will result in either end = kernel_start or start = kernel_end but in both cases will be end < start, and will either load initrd in the middle of the image, or arbitrarily at kernel_end. This patch reorganizes the conditionals to include so far unconsidered cases as well, uniformly returning the lowest available address. Fixes: 73b47eea2104 ('x86/dom0: improve PVH initrd and metadata placement') Signed-off-by: Xenia Ragiadakou <xenia.ragiadakou@amd.com> Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Roger Pau Monné <roger.pau@citrix.com> --- Changes in v3: - mention Zephyr in commit message (Roger) Changes in v2: - cover further cases of overlap (Jan) - mention with an in-code comment that a proper, more fine-grained solution can be implemented using a rangeset (Roger) xen/arch/x86/hvm/dom0_build.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-)