On Fri, Jan 23, 2026 at 10:43:12AM +0800, fanhuang wrote:
> +bool e820_update_entry_type(uint64_t start, uint64_t length, uint32_t
> new_type)
> +{
> + uint64_t end = start + length;
> + assert(!e820_done);
> +
> + /* For E820_SOFT_RESERVED, validate range is within E820_RAM */
> + if (new_type == E820_SOFT_RESERVED) {
> + bool range_in_ram = false;
> +
> + for (size_t j = 0; j < e820_entries; j++) {
> + uint64_t ram_start = le64_to_cpu(e820_table[j].address);
> + uint64_t ram_end = ram_start + le64_to_cpu(e820_table[j].length);
> + uint32_t ram_type = le32_to_cpu(e820_table[j].type);
> +
> + if (ram_type == E820_RAM && ram_start <= start && ram_end >=
> end) {
> + range_in_ram = true;
> + break;
> + }
> + }
> + if (!range_in_ram) {
> + return false;
> + }
> + }
------- nit --------
this can be shortened: (j == e820_entries) implies not found.
if (new_type == E820_SOFT_RESERVED) {
for (size_t j = 0; j < e820_entries; j++) {
uint64_t ram_start = le64_to_cpu(e820_table[j].address);
uint64_t ram_end = ram_start + le64_to_cpu(e820_table[j].length);
uint32_t ram_type = le32_to_cpu(e820_table[j].type);
if (ram_type == E820_RAM && ram_start <= start && ram_end >= end)
break;
}
if j == e820_entries: /* Not found */
return false;
}
Haven't looked at the surrounding code, this seems like you might define
static bool e820_has_ram_region(start, end) { /* above code */ }
then the 820_update_entry_type lines can just be
if (new_type == E820_SOFT_RESERVED &&
!e820_has_ram_region(start, end))
return false;
only worth it if e820_has_ram_region() deduplicates other stuff.
-------------------
I don't see anything else immediately concerning and the above is more
of a nit than anything.
I haven't tested this, you might at least add the OS-facing results to
the changelog so someone can replicate your setup.
For example the early-boot print showing E820 and ACPI SRAT data.
[reasonable memdev definitions]
-numa node,nodeid=0,memdev=m0
-numa node,nodeid=1,memdev=m1,memmap-type=spm
-numa node,nodeid=2,memdev=m2,memmap-type=reserved
resulting in:
[ 0.000000] BIOS-provided physical RAM map:
[ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x00000000afffffff] usable
[ 0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000c04fffffff] usable
[ 0.000000] BIOS-e820: [mem 0x000000c050000000-0x000001004fffffff] soft
reserved
[ 0.000000] BIOS-e820: [mem 0x0000010050000000-0x000001006fffffff] reserved
[ 0.003409] ACPI: SRAT: Node 0 PXM 0 [mem 0x00000000-0xafffffff]
[ 0.003410] ACPI: SRAT: Node 0 PXM 0 [mem 0x100000000-0xc04fffffff]
[ 0.003411] ACPI: SRAT: Node 1 PXM 1 [mem 0xc050000000-0x1004fffffff] hotplug
[ 0.003411] ACPI: SRAT: Node 2 PXM 2 [mem 0x10050000000-0x1006fffffff]
hotplug
(fake entries above)
(i don't actually know if RESERVED gets added to SRAT)
This would at least show the node-association and the types are correct.
Thanks,
~Gregory
