[PATCH] xen/dt: Don't advertise Xen static-heap region to hwdom

[PATCH] xen/dt: Don't advertise Xen static-heap region to hwdom

[Michal Orzel]

bootinfo.reserved_mem is used to store different types of memory that
Xen considers as reserved: domU static mem, normal /reserved-memory,
FDT memreserve and Xen static heap. make_memory_node(), invoked during
FDT generation for a hwdom for reserved memory, only skips the domU
static memory and FDT memreserve. This results in advertising Xen static
heap (if used) to a hwdom as /memory. This memory is not mapped in P2M
and guest attempt to access it fails. Interestingly, if the
/reserved-memory node is placed after /chosen, there is no problem because
of the check at the beginning of make_memory_node() that finds the first
memory range using the correct type.

Fixes: 4596329291f5 ("docs, xen/arm: Introduce static heap memory")
Signed-off-by: Michal Orzel <michal.orzel@amd.com>
---
 xen/common/device-tree/domain-build.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/xen/common/device-tree/domain-build.c b/xen/common/device-tree/domain-build.c
index 30a59abfa722..634a26946c24 100644
--- a/xen/common/device-tree/domain-build.c
+++ b/xen/common/device-tree/domain-build.c
@@ -541,8 +541,7 @@ int __init make_memory_node(const struct kernel_info *kinfo, int addrcells,
         u64 start = mem->bank[i].start;
         u64 size = mem->bank[i].size;
 
-        if ( (mem->bank[i].type == MEMBANK_STATIC_DOMAIN) ||
-             (mem->bank[i].type == MEMBANK_FDT_RESVMEM) )
+        if ( mem->bank[i].type != MEMBANK_DEFAULT )
             continue;
 
         nr_cells += reg_size;
-- 
2.43.0

Re: [PATCH] xen/dt: Don't advertise Xen static-heap region to hwdom

[Oleksii Kurochko]

On 10/29/26 11:43 AM, Michal Orzel wrote:
> bootinfo.reserved_mem is used to store different types of memory that
> Xen considers as reserved: domU static mem, normal /reserved-memory,
> FDT memreserve and Xen static heap. make_memory_node(), invoked during
> FDT generation for a hwdom for reserved memory, only skips the domU
> static memory and FDT memreserve. This results in advertising Xen static
> heap (if used) to a hwdom as /memory. This memory is not mapped in P2M
> and guest attempt to access it fails. Interestingly, if the
> /reserved-memory node is placed after /chosen, there is no problem because
> of the check at the beginning of make_memory_node() that finds the first
> memory range using the correct type.>
> Fixes: 4596329291f5 ("docs, xen/arm: Introduce static heap memory")
> Signed-off-by: Michal Orzel <michal.orzel@amd.com>

LGTM:

Reviewed-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>

~ Oleksii