b6eca183e2
While providing guests, it's desirable to resize it's memory on demand. By now, it's possible to do so by creating a guest with a small base memory, hot-plugging all the rest, and using 'movable_node' kernel command-line parameter, which puts all hot-plugged memory in ZONE_MOVABLE, allowing it to be removed whenever needed. But there is an issue regarding guest reboot: If memory is hot-plugged, and then the guest is rebooted, all hot-plugged memory goes to ZONE_NORMAL, which offers no guaranteed hot-removal. It usually prevents this memory to be hot-removed from the guest. It's possible to use device-tree information to fix that behavior, as it stores flags for LMB ranges on ibm,dynamic-memory-vN. It involves marking each memblock with the correct flags as hotpluggable memory, which mm/memblock.c puts in ZONE_MOVABLE during boot if 'movable_node' is passed. For carrying such information, the new flag DRCONF_MEM_HOTREMOVABLE was proposed and accepted into Power Architecture documentation. This flag should be: - true (b=1) if the hypervisor may want to hot-remove it later, and - false (b=0) if it does not care. During boot, guest kernel reads the device-tree, early_init_drmem_lmb() is called for every added LMBs. Here, checking for this new flag and marking memblocks as hotplugable memory is enough to get the desirable behavior. This should cause no change if 'movable_node' parameter is not passed in kernel command-line. Signed-off-by: Leonardo Bras <leonardo@linux.ibm.com> Reviewed-by: Bharata B Rao <bharata@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200402195156.626430-1-leonardo@linux.ibm.com
126 lines
2.8 KiB
C
126 lines
2.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* drmem.h: Power specific logical memory block representation
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*
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* Copyright 2017 IBM Corporation
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*/
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#ifndef _ASM_POWERPC_LMB_H
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#define _ASM_POWERPC_LMB_H
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struct drmem_lmb {
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u64 base_addr;
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u32 drc_index;
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u32 aa_index;
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u32 flags;
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#ifdef CONFIG_MEMORY_HOTPLUG
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int nid;
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#endif
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};
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struct drmem_lmb_info {
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struct drmem_lmb *lmbs;
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int n_lmbs;
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u32 lmb_size;
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};
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extern struct drmem_lmb_info *drmem_info;
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#define for_each_drmem_lmb_in_range(lmb, start, end) \
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for ((lmb) = (start); (lmb) < (end); (lmb)++)
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#define for_each_drmem_lmb(lmb) \
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for_each_drmem_lmb_in_range((lmb), \
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&drmem_info->lmbs[0], \
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&drmem_info->lmbs[drmem_info->n_lmbs])
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/*
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* The of_drconf_cell_v1 struct defines the layout of the LMB data
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* specified in the ibm,dynamic-memory device tree property.
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* The property itself is a 32-bit value specifying the number of
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* LMBs followed by an array of of_drconf_cell_v1 entries, one
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* per LMB.
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*/
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struct of_drconf_cell_v1 {
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__be64 base_addr;
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__be32 drc_index;
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__be32 reserved;
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__be32 aa_index;
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__be32 flags;
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};
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/*
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* Version 2 of the ibm,dynamic-memory property is defined as a
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* 32-bit value specifying the number of LMB sets followed by an
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* array of of_drconf_cell_v2 entries, one per LMB set.
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*/
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struct of_drconf_cell_v2 {
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u32 seq_lmbs;
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u64 base_addr;
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u32 drc_index;
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u32 aa_index;
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u32 flags;
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} __packed;
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#define DRCONF_MEM_ASSIGNED 0x00000008
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#define DRCONF_MEM_AI_INVALID 0x00000040
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#define DRCONF_MEM_RESERVED 0x00000080
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#define DRCONF_MEM_HOTREMOVABLE 0x00000100
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static inline u32 drmem_lmb_size(void)
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{
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return drmem_info->lmb_size;
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}
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#define DRMEM_LMB_RESERVED 0x80000000
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static inline void drmem_mark_lmb_reserved(struct drmem_lmb *lmb)
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{
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lmb->flags |= DRMEM_LMB_RESERVED;
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}
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static inline void drmem_remove_lmb_reservation(struct drmem_lmb *lmb)
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{
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lmb->flags &= ~DRMEM_LMB_RESERVED;
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}
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static inline bool drmem_lmb_reserved(struct drmem_lmb *lmb)
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{
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return lmb->flags & DRMEM_LMB_RESERVED;
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}
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u64 drmem_lmb_memory_max(void);
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void __init walk_drmem_lmbs(struct device_node *dn,
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void (*func)(struct drmem_lmb *, const __be32 **));
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int drmem_update_dt(void);
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#ifdef CONFIG_PPC_PSERIES
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void __init walk_drmem_lmbs_early(unsigned long node,
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void (*func)(struct drmem_lmb *, const __be32 **));
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#endif
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static inline void invalidate_lmb_associativity_index(struct drmem_lmb *lmb)
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{
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lmb->aa_index = 0xffffffff;
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}
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#ifdef CONFIG_MEMORY_HOTPLUG
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static inline void lmb_set_nid(struct drmem_lmb *lmb)
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{
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lmb->nid = memory_add_physaddr_to_nid(lmb->base_addr);
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}
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static inline void lmb_clear_nid(struct drmem_lmb *lmb)
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{
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lmb->nid = -1;
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}
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#else
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static inline void lmb_set_nid(struct drmem_lmb *lmb)
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{
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}
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static inline void lmb_clear_nid(struct drmem_lmb *lmb)
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{
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}
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#endif
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#endif /* _ASM_POWERPC_LMB_H */
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