| Message ID | 20190214104240.24428-2-jgross@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86: respect memory size limits | expand |
> On Feb 14, 2019, at 3:42 AM, Juergen Gross <jgross@suse.com> wrote: > > When limiting memory size via kernel parameter "mem=" this should be > respected even in case of memory made accessible via a PCI card. > > Today this kind of memory won't be made usable in initial memory > setup as the memory won't be visible in E820 map, but it might be > added when adding PCI devices due to corresponding ACPI table entries. > > Not respecting "mem=" can be corrected by adding a global max_mem_size > variable set by parse_memopt() which will result in rejecting adding > memory areas resulting in a memory size above the allowed limit. > > Signed-off-by: Juergen Gross <jgross@suse.com> > Acked-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: William Kucharski <william.kucharski@oracle.com>
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index 50895c2f937d..e67513e2cbbb 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -14,6 +14,7 @@ #include <linux/acpi.h> #include <linux/firmware-map.h> #include <linux/sort.h> +#include <linux/memory_hotplug.h> #include <asm/e820/api.h> #include <asm/setup.h> @@ -881,6 +882,10 @@ static int __init parse_memopt(char *p) e820__range_remove(mem_size, ULLONG_MAX - mem_size, E820_TYPE_RAM, 1); +#ifdef CONFIG_MEMORY_HOTPLUG + max_mem_size = mem_size; +#endif + return 0; } early_param("mem", parse_memopt); diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index 368267c1b71b..cfd12078172a 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -100,6 +100,8 @@ extern void __online_page_free(struct page *page); extern int try_online_node(int nid); +extern u64 max_mem_size; + extern bool memhp_auto_online; /* If movable_node boot option specified */ extern bool movable_node_enabled; diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 124e794867c5..519f9db063ff 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -96,10 +96,16 @@ void mem_hotplug_done(void) cpus_read_unlock(); } +u64 max_mem_size = U64_MAX; + /* add this memory to iomem resource */ static struct resource *register_memory_resource(u64 start, u64 size) { struct resource *res, *conflict; + + if (start + size > max_mem_size) + return ERR_PTR(-E2BIG); + res = kzalloc(sizeof(struct resource), GFP_KERNEL); if (!res) return ERR_PTR(-ENOMEM);