Hi Michal,
On 3/11/2024 9:46 PM, Michal Orzel wrote:
Hi Henry,
diff --git a/xen/arch/arm/dom0less-build.c b/xen/arch/arm/dom0less-build.c
index 1e1c8d83ae..99447bfb0c 100644
--- a/xen/arch/arm/dom0less-build.c
+++ b/xen/arch/arm/dom0less-build.c
@@ -682,6 +682,49 @@ static int __init prepare_dtb_domU(struct domain *d,
struct kernel_info *kinfo)
if ( kinfo->dom0less_feature & DOM0LESS_ENHANCED_NO_XS )
{
+ if ( is_domain_direct_mapped(d) )
+ {
This whole block is dependent on static memory feature that is compiled out by
default.
Shouldn't you move it to static-memory.c ?
This makes sense. I will convert this block to a function then move to
static-memory.c in v3.
+ struct meminfo *avail_magic_regions = xzalloc(struct meminfo);
I can't see corresponding xfree(avail_magic_regions). It's not going to be used
after unused memory
regions are retrieved.
Hmmm I realized I've made a mess here and below. I will do the proper
error handling in v3.
+ struct meminfo *rsrv_mem = &bootinfo.reserved_mem;
+ struct mem_map_domain *mem_map = &d->arch.mem_map;
+ uint64_t magic_region_start = INVALID_PADDR;
What's the purpose of this initialization? magic_region_start is going to be
re-assigned before making use of this value.
Personally for variables holding an address, I would like to init the
local variable to a poison value before use. But you are right it does
not make a difference here I think. I can drop the initialization if you
prefer not having it, sure.
+ uint64_t magic_region_size = GUEST_MAGIC_SIZE;
Why not paddr_t?
Good catch, I mixed struct meminfo with the newly added struct. Will use
paddr_t.
+
+ magic_region_start = avail_magic_regions->bank[0].start;
+
+ /*
+ * Register the magic region as reserved mem to make sure this
+ * region will not be counted when allocating extended regions.
Well, this is only true in case find_unallocated_memory() is used to retrieve
free regions.
What if our direct mapped domU used partial dtb and IOMMU is in use? In this
case,
find_memory_holes() will be used and the behavior will be different.
Also, I'm not sure if it is a good idea to call find_unused_memory twice (with
lots of steps inside)
just to retrieve 16MB (btw. add_ext_regions will only return 64MB+ regions)
region for magic pages.
I'll let other maintainers share their opinion.
I agree with your point. Let's wait a bit longer for more
ideas/comments. If no other inputs, I think I will drop the
"adding to reserved_mem" part of logic and record the found unused
memory in kinfo, then use rangeset_remove_range() to remove this range
in both
find_unallocated_memory() and find_memory_holes().
Also, CCing Carlo since he was in a need of retrieving free memory regions as
well for cache coloring with dom0.
(+ Carlo)
Any inputs from your side for this topic Carlo?
Kind regards,
Henry
~Michal
