From: David Hildenbrand <david@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: David Hildenbrand <david@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Mike Rapoport <rppt@kernel.org>, Michal Hocko <mhocko@suse.com>,
Oscar Salvador <osalvador@suse.de>,
Jianyong Wu <Jianyong.Wu@arm.com>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
Vineet Gupta <vgupta@kernel.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Huacai Chen <chenhuacai@kernel.org>,
Jiaxun Yang <jiaxun.yang@flygoat.com>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Eric Biederman <ebiederm@xmission.com>,
Arnd Bergmann <arnd@arndb.de>,
linux-snps-arc@lists.infradead.org, linux-ia64@vger.kernel.org,
linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org,
linux-s390@vger.kernel.org, linux-mm@kvack.org,
kexec@lists.infradead.org
Subject: [PATCH v1 3/4] memblock: add MEMBLOCK_DRIVER_MANAGED to mimic IORESOURCE_SYSRAM_DRIVER_MANAGED
Date: Mon, 27 Sep 2021 17:05:17 +0200 [thread overview]
Message-ID: <20210927150518.8607-4-david@redhat.com> (raw)
In-Reply-To: <20210927150518.8607-1-david@redhat.com>
Let's add a flag that corresponds to IORESOURCE_SYSRAM_DRIVER_MANAGED.
Similar to MEMBLOCK_HOTPLUG, most infrastructure has to treat such memory
like ordinary MEMBLOCK_NONE memory -- 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.
Let's document why kexec_walk_memblock() won't try placing images on
areas marked MEMBLOCK_DRIVER_MANAGED -- similar to
IORESOURCE_SYSRAM_DRIVER_MANAGED handling in locate_mem_hole_callback()
via kexec_walk_resources().
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.
Signed-off-by: David Hildenbrand <david@redhat.com>
---
include/linux/memblock.h | 16 ++++++++++++++--
kernel/kexec_file.c | 5 +++++
mm/memblock.c | 4 ++++
3 files changed, 23 insertions(+), 2 deletions(-)
diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index b49a58f621bc..7d8d656d5082 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -33,12 +33,17 @@ extern unsigned long long max_possible_pfn;
* @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 via a driver,
+ * corresponding to IORESOURCE_SYSRAM_DRIVER_MANAGED in the kernel resource
+ * tree. Especially kexec should never use this memory for placing images and
+ * shouldn't expose this memory to the second kernel.
*/
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 */
};
/**
@@ -209,7 +214,8 @@ static inline void __next_physmem_range(u64 *idx, struct memblock_type *type,
*/
#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
@@ -220,7 +226,8 @@ static inline void __next_physmem_range(u64 *idx, struct memblock_type *type,
*/
#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
@@ -250,6 +257,11 @@ static inline bool memblock_is_nomap(struct memblock_region *m)
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,
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 33400ff051a8..8347fc158d2b 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -556,6 +556,11 @@ static int kexec_walk_memblock(struct kexec_buf *kbuf,
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) {
diff --git a/mm/memblock.c b/mm/memblock.c
index 47a56b223141..540a35317fb0 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -979,6 +979,10 @@ static bool should_skip_region(struct memblock_type *type,
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;
}
--
2.31.1
next prev parent reply other threads:[~2021-09-27 15:06 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-27 15:05 [PATCH v1 0/4] mm/memory_hotplug: full support for David Hildenbrand
2021-09-27 15:05 ` [PATCH v1 1/4] mm/memory_hotplug: handle memblock_add_node() failures in add_memory_resource() David Hildenbrand
2021-09-27 15:05 ` [PATCH v1 2/4] memblock: allow to specify flags with memblock_add_node() David Hildenbrand
2021-09-27 15:19 ` Geert Uytterhoeven
2021-09-28 9:38 ` Heiko Carstens
2021-09-29 16:25 ` Mike Rapoport
2021-09-29 16:30 ` David Hildenbrand
2021-09-27 15:05 ` David Hildenbrand [this message]
2021-09-29 16:39 ` [PATCH v1 3/4] memblock: add MEMBLOCK_DRIVER_MANAGED to mimic IORESOURCE_SYSRAM_DRIVER_MANAGED Mike Rapoport
2021-09-29 16:54 ` David Hildenbrand
2021-09-30 21:21 ` Mike Rapoport
2021-10-01 8:04 ` David Hildenbrand
2021-10-01 14:03 ` Mike Rapoport
2021-09-27 15:05 ` [PATCH v1 4/4] mm/memory_hotplug: indicate MEMBLOCK_DRIVER_MANAGED with IORESOURCE_SYSRAM_DRIVER_MANAGED David Hildenbrand
2021-09-27 15:07 ` [PATCH v1 0/4] mm/memory_hotplug: full support for David Hildenbrand
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210927150518.8607-4-david@redhat.com \
--to=david@redhat.com \
--cc=Jianyong.Wu@arm.com \
--cc=akpm@linux-foundation.org \
--cc=aneesh.kumar@linux.ibm.com \
--cc=arnd@arndb.de \
--cc=borntraeger@de.ibm.com \
--cc=chenhuacai@kernel.org \
--cc=ebiederm@xmission.com \
--cc=geert@linux-m68k.org \
--cc=gor@linux.ibm.com \
--cc=hca@linux.ibm.com \
--cc=jiaxun.yang@flygoat.com \
--cc=kexec@lists.infradead.org \
--cc=linux-ia64@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-m68k@lists.linux-m68k.org \
--cc=linux-mips@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-s390@vger.kernel.org \
--cc=linux-snps-arc@lists.infradead.org \
--cc=mhocko@suse.com \
--cc=osalvador@suse.de \
--cc=rppt@kernel.org \
--cc=tsbogend@alpha.franken.de \
--cc=vgupta@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).