The patch titled
Subject: virtio-mem: support CONFIG_PROC_VMCORE_DEVICE_RAM
has been added to the -mm mm-unstable branch. Its filename is
virtio-mem-support-config_proc_vmcore_device_ram.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/virtio-mem-support-config_proc_vmcore_device_ram.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: virtio-mem: support CONFIG_PROC_VMCORE_DEVICE_RAM
Date: Wed, 4 Dec 2024 13:54:42 +0100
Let's implement the get_device_ram() vmcore callback, so architectures
that select NEED_PROC_VMCORE_NEED_DEVICE_RAM, like s390 soon, can include
that memory in a crash dump.
Merge ranges, and process ranges that might contain a mixture of plugged
and unplugged, to reduce the total number of ranges.
Link: https://lkml.kernel.org/r/20241204125444.1734652-12-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx>
Cc: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
Cc: Cornelia Huck <cohuck@xxxxxxxxxx>
Cc: Dave Young <dyoung@xxxxxxxxxx>
Cc: Eric Farman <farman@xxxxxxxxxxxxx>
Cc: Eugenio Pérez <eperezma@xxxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Janosch Frank <frankja@xxxxxxxxxxxxx>
Cc: Jason Wang <jasowang@xxxxxxxxxx>
Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
Cc: Sven Schnelle <svens@xxxxxxxxxxxxx>
Cc: Thomas Huth <thuth@xxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/virtio/virtio_mem.c | 88 ++++++++++++++++++++++++++++++++++
fs/proc/Kconfig | 1
2 files changed, 89 insertions(+)
--- a/drivers/virtio/virtio_mem.c~virtio-mem-support-config_proc_vmcore_device_ram
+++ a/drivers/virtio/virtio_mem.c
@@ -2728,6 +2728,91 @@ static bool virtio_mem_vmcore_pfn_is_ram
mutex_unlock(&vm->hotplug_mutex);
return is_ram;
}
+
+#ifdef CONFIG_PROC_VMCORE_DEVICE_RAM
+static int virtio_mem_vmcore_add_device_ram(struct virtio_mem *vm,
+ struct list_head *list, uint64_t start, uint64_t end)
+{
+ int rc;
+
+ rc = vmcore_alloc_add_range(list, start, end - start);
+ if (rc)
+ dev_err(&vm->vdev->dev,
+ "Error adding device RAM range: %d\n", rc);
+ return rc;
+}
+
+static int virtio_mem_vmcore_get_device_ram(struct vmcore_cb *cb,
+ struct list_head *list)
+{
+ struct virtio_mem *vm = container_of(cb, struct virtio_mem,
+ vmcore_cb);
+ const uint64_t device_start = vm->addr;
+ const uint64_t device_end = vm->addr + vm->usable_region_size;
+ uint64_t chunk_size, cur_start, cur_end, plugged_range_start = 0;
+ LIST_HEAD(tmp_list);
+ int rc;
+
+ if (!vm->plugged_size)
+ return 0;
+
+ /* Process memory sections, unless the device block size is bigger. */
+ chunk_size = max_t(uint64_t, PFN_PHYS(PAGES_PER_SECTION),
+ vm->device_block_size);
+
+ mutex_lock(&vm->hotplug_mutex);
+
+ /*
+ * We process larger chunks and indicate the complete chunk if any
+ * block in there is plugged. This reduces the number of pfn_is_ram()
+ * callbacks and mimic what is effectively being done when the old
+ * kernel would add complete memory sections/blocks to the elfcore hdr.
+ */
+ cur_start = device_start;
+ for (cur_start = device_start; cur_start < device_end; cur_start = cur_end) {
+ cur_end = ALIGN_DOWN(cur_start + chunk_size, chunk_size);
+ cur_end = min_t(uint64_t, cur_end, device_end);
+
+ rc = virtio_mem_send_state_request(vm, cur_start,
+ cur_end - cur_start);
+
+ if (rc < 0) {
+ dev_err(&vm->vdev->dev,
+ "Error querying block states: %d\n", rc);
+ goto out;
+ } else if (rc != VIRTIO_MEM_STATE_UNPLUGGED) {
+ /* Merge ranges with plugged memory. */
+ if (!plugged_range_start)
+ plugged_range_start = cur_start;
+ continue;
+ }
+
+ /* Flush any plugged range. */
+ if (plugged_range_start) {
+ rc = virtio_mem_vmcore_add_device_ram(vm, &tmp_list,
+ plugged_range_start,
+ cur_start);
+ if (rc)
+ goto out;
+ plugged_range_start = 0;
+ }
+ }
+
+ /* Flush any plugged range. */
+ if (plugged_range_start)
+ rc = virtio_mem_vmcore_add_device_ram(vm, &tmp_list,
+ plugged_range_start,
+ cur_start);
+out:
+ mutex_unlock(&vm->hotplug_mutex);
+ if (rc < 0) {
+ vmcore_free_ranges(&tmp_list);
+ return rc;
+ }
+ list_splice_tail(&tmp_list, list);
+ return 0;
+}
+#endif /* CONFIG_PROC_VMCORE_DEVICE_RAM */
#endif /* CONFIG_PROC_VMCORE */
static int virtio_mem_init_kdump(struct virtio_mem *vm)
@@ -2737,6 +2822,9 @@ static int virtio_mem_init_kdump(struct
#ifdef CONFIG_PROC_VMCORE
dev_info(&vm->vdev->dev, "memory hot(un)plug disabled in kdump kernel\n");
vm->vmcore_cb.pfn_is_ram = virtio_mem_vmcore_pfn_is_ram;
+#ifdef CONFIG_PROC_VMCORE_DEVICE_RAM
+ vm->vmcore_cb.get_device_ram = virtio_mem_vmcore_get_device_ram;
+#endif /* CONFIG_PROC_VMCORE_DEVICE_RAM */
register_vmcore_cb(&vm->vmcore_cb);
return 0;
#else /* CONFIG_PROC_VMCORE */
--- a/fs/proc/Kconfig~virtio-mem-support-config_proc_vmcore_device_ram
+++ a/fs/proc/Kconfig
@@ -67,6 +67,7 @@ config NEED_PROC_VMCORE_DEVICE_RAM
config PROC_VMCORE_DEVICE_RAM
def_bool y
depends on PROC_VMCORE && NEED_PROC_VMCORE_DEVICE_RAM
+ depends on VIRTIO_MEM
help
If the elfcore hdr is allocated and prepared by the dump kernel
("2nd kernel") instead of the crashed kernel, RAM provided by memory
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
mm-mempolicy-fix-migrate_to_node-assuming-there-is-at-least-one-vma-in-a-mm.patch
mm-filemap-dont-call-folio_test_locked-without-a-reference-in-next_uptodate_folio.patch
docs-tmpfs-update-the-large-folios-policy-for-tmpfs-and-shmem.patch
mm-memory_hotplug-move-debug_pagealloc_map_pages-into-online_pages_range.patch
mm-page_isolation-dont-pass-gfp-flags-to-isolate_single_pageblock.patch
mm-page_isolation-dont-pass-gfp-flags-to-start_isolate_page_range.patch
mm-page_alloc-make-__alloc_contig_migrate_range-static.patch
mm-page_alloc-sort-out-the-alloc_contig_range-gfp-flags-mess.patch
mm-page_alloc-forward-the-gfp-flags-from-alloc_contig_range-to-post_alloc_hook.patch
powernv-memtrace-use-__gfp_zero-with-alloc_contig_pages.patch
mm-hugetlb-dont-map-folios-writable-without-vm_write-when-copying-during-fork.patch
fs-proc-vmcore-convert-vmcore_cb_lock-into-vmcore_mutex.patch
fs-proc-vmcore-replace-vmcoredd_mutex-by-vmcore_mutex.patch
fs-proc-vmcore-disallow-vmcore-modifications-while-the-vmcore-is-open.patch
fs-proc-vmcore-prefix-all-pr_-with-vmcore.patch
fs-proc-vmcore-move-vmcore-definitions-out-of-kcoreh.patch
fs-proc-vmcore-factor-out-allocating-a-vmcore-range-and-adding-it-to-a-list.patch
fs-proc-vmcore-factor-out-freeing-a-list-of-vmcore-ranges.patch
fs-proc-vmcore-introduce-proc_vmcore_device_ram-to-detect-device-ram-ranges-in-2nd-kernel.patch
virtio-mem-mark-device-ready-before-registering-callbacks-in-kdump-mode.patch
virtio-mem-remember-usable-region-size.patch
virtio-mem-support-config_proc_vmcore_device_ram.patch
s390-kdump-virtio-mem-kdump-support-config_proc_vmcore_device_ram.patch
