From 890a4212de718fcbb4ba4ee36569af31908d9dc5 Mon Sep 17 00:00:00 2001 From: Sumanth Korikkar Date: Mon, 8 Jan 2024 14:27:46 +0100 Subject: [PATCH] s390/mm: implement MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers MEM_PREPARE_ONLINE memory notifier makes memory block physical accessible via sclp assign command. The notifier ensures self-contained memory maps are accessible and hence enabling the "memmap on memory" on s390. MEM_FINISH_OFFLINE memory notifier shifts the memory block to an inaccessible state via sclp unassign command. Implementation considerations: * When MHP_MEMMAP_ON_MEMORY is disabled, the system retains the old behavior. This means the memory map is allocated from default memory. * If MACHINE_HAS_EDAT1 is unavailable, MHP_MEMMAP_ON_MEMORY is automatically disabled. This ensures that vmemmap pagetables do not consume additional memory from the default memory allocator. * The MEM_GOING_ONLINE notifier has been modified to perform no operation, as MEM_PREPARE_ONLINE already executes the sclp assign command. * The MEM_CANCEL_ONLINE/MEM_OFFLINE notifier now performs no operation, as MEM_FINISH_OFFLINE already executes the sclp unassign command. Link: https://lkml.kernel.org/r/20240108132747.3238763-5-sumanthk@linux.ibm.com Reviewed-by: Gerald Schaefer Reviewed-by: David Hildenbrand Signed-off-by: Sumanth Korikkar Cc: Alexander Gordeev Cc: Aneesh Kumar K.V Cc: Anshuman Khandual Cc: Heiko Carstens Cc: Michal Hocko Cc: Oscar Salvador Cc: Vasily Gorbik Signed-off-by: Andrew Morton --- drivers/s390/char/sclp_cmd.c | 41 ++++++++++++++++++++++++++++++------ 1 file changed, 35 insertions(+), 6 deletions(-) diff --git a/drivers/s390/char/sclp_cmd.c b/drivers/s390/char/sclp_cmd.c index 355e63e44e95..7815e9bea69a 100644 --- a/drivers/s390/char/sclp_cmd.c +++ b/drivers/s390/char/sclp_cmd.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -26,6 +27,7 @@ #include #include #include +#include #include "sclp.h" @@ -340,13 +342,38 @@ static int sclp_mem_notifier(struct notifier_block *nb, if (contains_standby_increment(start, start + size)) rc = -EPERM; break; - case MEM_GOING_ONLINE: + case MEM_PREPARE_ONLINE: + /* + * Access the altmap_start_pfn and altmap_nr_pages fields + * within the struct memory_notify specifically when dealing + * with only MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers. + * + * When altmap is in use, take the specified memory range + * online, which includes the altmap. + */ + if (arg->altmap_nr_pages) { + start = PFN_PHYS(arg->altmap_start_pfn); + size += PFN_PHYS(arg->altmap_nr_pages); + } rc = sclp_mem_change_state(start, size, 1); + if (rc || !arg->altmap_nr_pages) + break; + /* + * Set CMMA state to nodat here, since the struct page memory + * at the beginning of the memory block will not go through the + * buddy allocator later. + */ + __arch_set_page_nodat((void *)__va(start), arg->altmap_nr_pages); break; - case MEM_CANCEL_ONLINE: - sclp_mem_change_state(start, size, 0); - break; - case MEM_OFFLINE: + case MEM_FINISH_OFFLINE: + /* + * When altmap is in use, take the specified memory range + * offline, which includes the altmap. + */ + if (arg->altmap_nr_pages) { + start = PFN_PHYS(arg->altmap_start_pfn); + size += PFN_PHYS(arg->altmap_nr_pages); + } sclp_mem_change_state(start, size, 0); break; default: @@ -397,7 +424,9 @@ static void __init add_memory_merged(u16 rn) if (!size) goto skip_add; for (addr = start; addr < start + size; addr += block_size) - add_memory(0, addr, block_size, MHP_NONE); + add_memory(0, addr, block_size, + MACHINE_HAS_EDAT1 ? + MHP_MEMMAP_ON_MEMORY | MHP_OFFLINE_INACCESSIBLE : MHP_NONE); skip_add: first_rn = rn; num = 1; -- 2.25.1