The patch titled
Subject: memblock: add MEMBLOCK_DRIVER_MANAGED to mimic IORESOURCE_SYSRAM_DRIVER_MANAGED
has been added to the -mm tree. Its filename is
memblock-add-memblock_driver_managed-to-mimic-ioresource_sysram_driver_managed.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/memblock-add-memblock_driver_managed-to-mimic-ioresource_sysram_driver_managed.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/memblock-add-memblock_driver_managed-to-mimic-ioresource_sysram_driver_managed.patch
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------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: memblock: add MEMBLOCK_DRIVER_MANAGED to mimic IORESOURCE_SYSRAM_DRIVER_MANAGED
Let's add a flag that corresponds to IORESOURCE_SYSRAM_DRIVER_MANAGED,
indicating that we're dealing with a memory region that is never indicated
in the firmware-provided memory map, but always detected and added by a
driver.
Similar to MEMBLOCK_HOTPLUG, most infrastructure has to treat such memory
regions like ordinary MEMBLOCK_NONE memory regions -- for example, when
selecting memory regions to add to the vmcore for dumping in the
crashkernel via for_each_mem_range().
However, especially kexec_file is not supposed to select such memblocks
via for_each_free_mem_range() / for_each_free_mem_range_reverse() to place
kexec images, similar to how we handle IORESOURCE_SYSRAM_DRIVER_MANAGED
without CONFIG_ARCH_KEEP_MEMBLOCK.
We'll make sure that memory hotplug code sets the flag where applicable
(IORESOURCE_SYSRAM_DRIVER_MANAGED) next. This prepares architectures that
need CONFIG_ARCH_KEEP_MEMBLOCK, such as arm64, for virtio-mem support.
Note that kexec *must not* indicate this memory to the second kernel and
*must not* place kexec-images on this memory. Let's add a comment to
kexec_walk_memblock(), documenting how we handle MEMBLOCK_DRIVER_MANAGED
now just like using IORESOURCE_SYSRAM_DRIVER_MANAGED in
locate_mem_hole_callback() for kexec_walk_resources().
Also note that MEMBLOCK_HOTPLUG cannot be reused due to different
semantics:
MEMBLOCK_HOTPLUG: memory is indicated as "System RAM" in the
firmware-provided memory map and added to the system early during
boot; kexec *has to* indicate this memory to the second kernel and
can place kexec-images on this memory. After memory hotunplug,
kexec has to be re-armed. We mostly ignore this flag when
"movable_node" is not set on the kernel command line, because
then we're told to not care about hotunpluggability of such
memory regions.
MEMBLOCK_DRIVER_MANAGED: memory is not indicated as "System RAM" in
the firmware-provided memory map; this memory is always detected
and added to the system by a driver; memory might not actually be
physically hotunpluggable. kexec *must not* indicate this memory to
the second kernel and *must not* place kexec-images on this memory.
Link: https://lkml.kernel.org/r/20211004093605.5830-5-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@xxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Huacai Chen <chenhuacai@xxxxxxxxxx>
Cc: Jianyong Wu <Jianyong.Wu@xxxxxxx>
Cc: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Shahab Vahedi <shahab@xxxxxxxxxxxx>
Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Vineet Gupta <vgupta@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/memblock.h | 16 ++++++++++++++--
kernel/kexec_file.c | 5 +++++
mm/memblock.c | 4 ++++
3 files changed, 23 insertions(+), 2 deletions(-)
--- a/include/linux/memblock.h~memblock-add-memblock_driver_managed-to-mimic-ioresource_sysram_driver_managed
+++ a/include/linux/memblock.h
@@ -37,12 +37,17 @@ extern unsigned long long max_possible_p
* @MEMBLOCK_NOMAP: don't add to kernel direct mapping and treat as
* reserved in the memory map; refer to memblock_mark_nomap() description
* for further details
+ * @MEMBLOCK_DRIVER_MANAGED: memory region that is always detected and added
+ * via a driver, and never indicated in the firmware-provided memory map as
+ * system RAM. This corresponds to IORESOURCE_SYSRAM_DRIVER_MANAGED in the
+ * kernel resource tree.
*/
enum memblock_flags {
MEMBLOCK_NONE = 0x0, /* No special request */
MEMBLOCK_HOTPLUG = 0x1, /* hotpluggable region */
MEMBLOCK_MIRROR = 0x2, /* mirrored region */
MEMBLOCK_NOMAP = 0x4, /* don't add to kernel direct mapping */
+ MEMBLOCK_DRIVER_MANAGED = 0x8, /* always detected via a driver */
};
/**
@@ -213,7 +218,8 @@ static inline void __next_physmem_range(
*/
#define for_each_mem_range(i, p_start, p_end) \
__for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE, \
- MEMBLOCK_HOTPLUG, p_start, p_end, NULL)
+ MEMBLOCK_HOTPLUG | MEMBLOCK_DRIVER_MANAGED, \
+ p_start, p_end, NULL)
/**
* for_each_mem_range_rev - reverse iterate through memblock areas from
@@ -224,7 +230,8 @@ static inline void __next_physmem_range(
*/
#define for_each_mem_range_rev(i, p_start, p_end) \
__for_each_mem_range_rev(i, &memblock.memory, NULL, NUMA_NO_NODE, \
- MEMBLOCK_HOTPLUG, p_start, p_end, NULL)
+ MEMBLOCK_HOTPLUG | MEMBLOCK_DRIVER_MANAGED,\
+ p_start, p_end, NULL)
/**
* for_each_reserved_mem_range - iterate over all reserved memblock areas
@@ -254,6 +261,11 @@ static inline bool memblock_is_nomap(str
return m->flags & MEMBLOCK_NOMAP;
}
+static inline bool memblock_is_driver_managed(struct memblock_region *m)
+{
+ return m->flags & MEMBLOCK_DRIVER_MANAGED;
+}
+
int memblock_search_pfn_nid(unsigned long pfn, unsigned long *start_pfn,
unsigned long *end_pfn);
void __next_mem_pfn_range(int *idx, int nid, unsigned long *out_start_pfn,
--- a/kernel/kexec_file.c~memblock-add-memblock_driver_managed-to-mimic-ioresource_sysram_driver_managed
+++ a/kernel/kexec_file.c
@@ -556,6 +556,11 @@ static int kexec_walk_memblock(struct ke
if (kbuf->image->type == KEXEC_TYPE_CRASH)
return func(&crashk_res, kbuf);
+ /*
+ * Using MEMBLOCK_NONE will properly skip MEMBLOCK_DRIVER_MANAGED. See
+ * IORESOURCE_SYSRAM_DRIVER_MANAGED handling in
+ * locate_mem_hole_callback().
+ */
if (kbuf->top_down) {
for_each_free_mem_range_reverse(i, NUMA_NO_NODE, MEMBLOCK_NONE,
&mstart, &mend, NULL) {
--- a/mm/memblock.c~memblock-add-memblock_driver_managed-to-mimic-ioresource_sysram_driver_managed
+++ a/mm/memblock.c
@@ -979,6 +979,10 @@ static bool should_skip_region(struct me
if (!(flags & MEMBLOCK_NOMAP) && memblock_is_nomap(m))
return true;
+ /* skip driver-managed memory unless we were asked for it explicitly */
+ if (!(flags & MEMBLOCK_DRIVER_MANAGED) && memblock_is_driver_managed(m))
+ return true;
+
return false;
}
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
memory-hotplugrst-fix-two-instances-of-movablecore-that-should-be-movable_node.patch
memory-hotplugrst-fix-wrong-sys-module-memory_hotplug-parameters-path.patch
memory-hotplugrst-document-the-auto-movable-online-policy.patch
mm-memory_hotplug-remove-config_x86_64_acpi_numa-dependency-from-config_memory_hotplug.patch
mm-memory_hotplug-remove-config_memory_hotplug_sparse.patch
mm-memory_hotplug-restrict-config_memory_hotplug-to-64-bit.patch
mm-memory_hotplug-remove-highmem-leftovers.patch
mm-memory_hotplug-remove-stale-function-declarations.patch
x86-remove-memory-hotplug-support-on-x86_32.patch
mm-memory_hotplug-handle-memblock_add_node-failures-in-add_memory_resource.patch
memblock-improve-memblock_hotplug-documentation.patch
memblock-allow-to-specify-flags-with-memblock_add_node.patch
memblock-add-memblock_driver_managed-to-mimic-ioresource_sysram_driver_managed.patch
mm-memory_hotplug-indicate-memblock_driver_managed-with-ioresource_sysram_driver_managed.patch
x86-xen-update-xen_oldmem_pfn_is_ram-documentation.patch
x86-xen-simplify-xen_oldmem_pfn_is_ram.patch
x86-xen-print-a-warning-when-hvmop_get_mem_type-fails.patch
proc-vmcore-let-pfn_is_ram-return-a-bool.patch
proc-vmcore-convert-oldmem_pfn_is_ram-callback-to-more-generic-vmcore-callbacks.patch
virtio-mem-factor-out-hotplug-specifics-from-virtio_mem_init-into-virtio_mem_init_hotplug.patch
virtio-mem-factor-out-hotplug-specifics-from-virtio_mem_probe-into-virtio_mem_init_hotplug.patch
virtio-mem-factor-out-hotplug-specifics-from-virtio_mem_remove-into-virtio_mem_deinit_hotplug.patch
virtio-mem-kdump-mode-to-sanitize-proc-vmcore-access.patch
kernel-resource-clean-up-and-optimize-iomem_is_exclusive.patch
kernel-resource-disallow-access-to-exclusive-system-ram-regions.patch
virtio-mem-disallow-mapping-virtio-mem-memory-via-dev-mem.patch
