cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
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kvm_book3s.h (17406B)


      1/* SPDX-License-Identifier: GPL-2.0-only */
      2/*
      3 *
      4 * Copyright SUSE Linux Products GmbH 2009
      5 *
      6 * Authors: Alexander Graf <agraf@suse.de>
      7 */
      8
      9#ifndef __ASM_KVM_BOOK3S_H__
     10#define __ASM_KVM_BOOK3S_H__
     11
     12#include <linux/types.h>
     13#include <linux/kvm_host.h>
     14#include <asm/kvm_book3s_asm.h>
     15
     16struct kvmppc_bat {
     17	u64 raw;
     18	u32 bepi;
     19	u32 bepi_mask;
     20	u32 brpn;
     21	u8 wimg;
     22	u8 pp;
     23	bool vs		: 1;
     24	bool vp		: 1;
     25};
     26
     27struct kvmppc_sid_map {
     28	u64 guest_vsid;
     29	u64 guest_esid;
     30	u64 host_vsid;
     31	bool valid	: 1;
     32};
     33
     34#define SID_MAP_BITS    9
     35#define SID_MAP_NUM     (1 << SID_MAP_BITS)
     36#define SID_MAP_MASK    (SID_MAP_NUM - 1)
     37
     38#ifdef CONFIG_PPC_BOOK3S_64
     39#define SID_CONTEXTS	1
     40#else
     41#define SID_CONTEXTS	128
     42#define VSID_POOL_SIZE	(SID_CONTEXTS * 16)
     43#endif
     44
     45struct hpte_cache {
     46	struct hlist_node list_pte;
     47	struct hlist_node list_pte_long;
     48	struct hlist_node list_vpte;
     49	struct hlist_node list_vpte_long;
     50#ifdef CONFIG_PPC_BOOK3S_64
     51	struct hlist_node list_vpte_64k;
     52#endif
     53	struct rcu_head rcu_head;
     54	u64 host_vpn;
     55	u64 pfn;
     56	ulong slot;
     57	struct kvmppc_pte pte;
     58	int pagesize;
     59};
     60
     61/*
     62 * Struct for a virtual core.
     63 * Note: entry_exit_map combines a bitmap of threads that have entered
     64 * in the bottom 8 bits and a bitmap of threads that have exited in the
     65 * next 8 bits.  This is so that we can atomically set the entry bit
     66 * iff the exit map is 0 without taking a lock.
     67 */
     68struct kvmppc_vcore {
     69	int n_runnable;
     70	int num_threads;
     71	int entry_exit_map;
     72	int napping_threads;
     73	int first_vcpuid;
     74	u16 pcpu;
     75	u16 last_cpu;
     76	u8 vcore_state;
     77	u8 in_guest;
     78	struct kvm_vcpu *runnable_threads[MAX_SMT_THREADS];
     79	struct list_head preempt_list;
     80	spinlock_t lock;
     81	struct rcuwait wait;
     82	spinlock_t stoltb_lock;	/* protects stolen_tb and preempt_tb */
     83	u64 stolen_tb;
     84	u64 preempt_tb;
     85	struct kvm_vcpu *runner;
     86	struct kvm *kvm;
     87	u64 tb_offset;		/* guest timebase - host timebase */
     88	u64 tb_offset_applied;	/* timebase offset currently in force */
     89	ulong lpcr;
     90	u32 arch_compat;
     91	ulong pcr;
     92	ulong dpdes;		/* doorbell state (POWER8) */
     93	ulong vtb;		/* virtual timebase */
     94	ulong conferring_threads;
     95	unsigned int halt_poll_ns;
     96	atomic_t online_count;
     97};
     98
     99struct kvmppc_vcpu_book3s {
    100	struct kvmppc_sid_map sid_map[SID_MAP_NUM];
    101	struct {
    102		u64 esid;
    103		u64 vsid;
    104	} slb_shadow[64];
    105	u8 slb_shadow_max;
    106	struct kvmppc_bat ibat[8];
    107	struct kvmppc_bat dbat[8];
    108	u64 hid[6];
    109	u64 gqr[8];
    110	u64 sdr1;
    111	u64 hior;
    112	u64 msr_mask;
    113	u64 vtb;
    114#ifdef CONFIG_PPC_BOOK3S_32
    115	u32 vsid_pool[VSID_POOL_SIZE];
    116	u32 vsid_next;
    117#else
    118	u64 proto_vsid_first;
    119	u64 proto_vsid_max;
    120	u64 proto_vsid_next;
    121#endif
    122	int context_id[SID_CONTEXTS];
    123
    124	bool hior_explicit;		/* HIOR is set by ioctl, not PVR */
    125
    126	struct hlist_head hpte_hash_pte[HPTEG_HASH_NUM_PTE];
    127	struct hlist_head hpte_hash_pte_long[HPTEG_HASH_NUM_PTE_LONG];
    128	struct hlist_head hpte_hash_vpte[HPTEG_HASH_NUM_VPTE];
    129	struct hlist_head hpte_hash_vpte_long[HPTEG_HASH_NUM_VPTE_LONG];
    130#ifdef CONFIG_PPC_BOOK3S_64
    131	struct hlist_head hpte_hash_vpte_64k[HPTEG_HASH_NUM_VPTE_64K];
    132#endif
    133	int hpte_cache_count;
    134	spinlock_t mmu_lock;
    135};
    136
    137#define VSID_REAL	0x07ffffffffc00000ULL
    138#define VSID_BAT	0x07ffffffffb00000ULL
    139#define VSID_64K	0x0800000000000000ULL
    140#define VSID_1T		0x1000000000000000ULL
    141#define VSID_REAL_DR	0x2000000000000000ULL
    142#define VSID_REAL_IR	0x4000000000000000ULL
    143#define VSID_PR		0x8000000000000000ULL
    144
    145extern void kvmppc_mmu_pte_flush(struct kvm_vcpu *vcpu, ulong ea, ulong ea_mask);
    146extern void kvmppc_mmu_pte_vflush(struct kvm_vcpu *vcpu, u64 vp, u64 vp_mask);
    147extern void kvmppc_mmu_pte_pflush(struct kvm_vcpu *vcpu, ulong pa_start, ulong pa_end);
    148extern void kvmppc_set_msr(struct kvm_vcpu *vcpu, u64 new_msr);
    149extern void kvmppc_mmu_book3s_64_init(struct kvm_vcpu *vcpu);
    150extern void kvmppc_mmu_book3s_32_init(struct kvm_vcpu *vcpu);
    151extern void kvmppc_mmu_book3s_hv_init(struct kvm_vcpu *vcpu);
    152extern int kvmppc_mmu_map_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *pte,
    153			       bool iswrite);
    154extern void kvmppc_mmu_unmap_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *pte);
    155extern int kvmppc_mmu_map_segment(struct kvm_vcpu *vcpu, ulong eaddr);
    156extern void kvmppc_mmu_flush_segment(struct kvm_vcpu *vcpu, ulong eaddr, ulong seg_size);
    157extern void kvmppc_mmu_flush_segments(struct kvm_vcpu *vcpu);
    158extern int kvmppc_book3s_hv_page_fault(struct kvm_vcpu *vcpu,
    159			unsigned long addr, unsigned long status);
    160extern long kvmppc_hv_find_lock_hpte(struct kvm *kvm, gva_t eaddr,
    161			unsigned long slb_v, unsigned long valid);
    162extern int kvmppc_hv_emulate_mmio(struct kvm_vcpu *vcpu,
    163			unsigned long gpa, gva_t ea, int is_store);
    164
    165extern void kvmppc_mmu_hpte_cache_map(struct kvm_vcpu *vcpu, struct hpte_cache *pte);
    166extern struct hpte_cache *kvmppc_mmu_hpte_cache_next(struct kvm_vcpu *vcpu);
    167extern void kvmppc_mmu_hpte_cache_free(struct hpte_cache *pte);
    168extern void kvmppc_mmu_hpte_destroy(struct kvm_vcpu *vcpu);
    169extern int kvmppc_mmu_hpte_init(struct kvm_vcpu *vcpu);
    170extern void kvmppc_mmu_invalidate_pte(struct kvm_vcpu *vcpu, struct hpte_cache *pte);
    171extern int kvmppc_mmu_hpte_sysinit(void);
    172extern void kvmppc_mmu_hpte_sysexit(void);
    173extern int kvmppc_mmu_hv_init(void);
    174extern int kvmppc_book3s_hcall_implemented(struct kvm *kvm, unsigned long hc);
    175
    176extern int kvmppc_book3s_radix_page_fault(struct kvm_vcpu *vcpu,
    177			unsigned long ea, unsigned long dsisr);
    178extern unsigned long __kvmhv_copy_tofrom_guest_radix(int lpid, int pid,
    179					gva_t eaddr, void *to, void *from,
    180					unsigned long n);
    181extern long kvmhv_copy_from_guest_radix(struct kvm_vcpu *vcpu, gva_t eaddr,
    182					void *to, unsigned long n);
    183extern long kvmhv_copy_to_guest_radix(struct kvm_vcpu *vcpu, gva_t eaddr,
    184				      void *from, unsigned long n);
    185extern int kvmppc_mmu_walk_radix_tree(struct kvm_vcpu *vcpu, gva_t eaddr,
    186				      struct kvmppc_pte *gpte, u64 root,
    187				      u64 *pte_ret_p);
    188extern int kvmppc_mmu_radix_translate_table(struct kvm_vcpu *vcpu, gva_t eaddr,
    189			struct kvmppc_pte *gpte, u64 table,
    190			int table_index, u64 *pte_ret_p);
    191extern int kvmppc_mmu_radix_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
    192			struct kvmppc_pte *gpte, bool data, bool iswrite);
    193extern void kvmppc_radix_tlbie_page(struct kvm *kvm, unsigned long addr,
    194				    unsigned int pshift, unsigned int lpid);
    195extern void kvmppc_unmap_pte(struct kvm *kvm, pte_t *pte, unsigned long gpa,
    196			unsigned int shift,
    197			const struct kvm_memory_slot *memslot,
    198			unsigned int lpid);
    199extern bool kvmppc_hv_handle_set_rc(struct kvm *kvm, bool nested,
    200				    bool writing, unsigned long gpa,
    201				    unsigned int lpid);
    202extern int kvmppc_book3s_instantiate_page(struct kvm_vcpu *vcpu,
    203				unsigned long gpa,
    204				struct kvm_memory_slot *memslot,
    205				bool writing, bool kvm_ro,
    206				pte_t *inserted_pte, unsigned int *levelp);
    207extern int kvmppc_init_vm_radix(struct kvm *kvm);
    208extern void kvmppc_free_radix(struct kvm *kvm);
    209extern void kvmppc_free_pgtable_radix(struct kvm *kvm, pgd_t *pgd,
    210				      unsigned int lpid);
    211extern int kvmppc_radix_init(void);
    212extern void kvmppc_radix_exit(void);
    213extern void kvm_unmap_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
    214			    unsigned long gfn);
    215extern bool kvm_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
    216			  unsigned long gfn);
    217extern bool kvm_test_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
    218			       unsigned long gfn);
    219extern long kvmppc_hv_get_dirty_log_radix(struct kvm *kvm,
    220			struct kvm_memory_slot *memslot, unsigned long *map);
    221extern void kvmppc_radix_flush_memslot(struct kvm *kvm,
    222			const struct kvm_memory_slot *memslot);
    223extern int kvmhv_get_rmmu_info(struct kvm *kvm, struct kvm_ppc_rmmu_info *info);
    224
    225/* XXX remove this export when load_last_inst() is generic */
    226extern int kvmppc_ld(struct kvm_vcpu *vcpu, ulong *eaddr, int size, void *ptr, bool data);
    227extern void kvmppc_book3s_queue_irqprio(struct kvm_vcpu *vcpu, unsigned int vec);
    228extern void kvmppc_book3s_dequeue_irqprio(struct kvm_vcpu *vcpu,
    229					  unsigned int vec);
    230extern void kvmppc_inject_interrupt(struct kvm_vcpu *vcpu, int vec, u64 flags);
    231extern void kvmppc_trigger_fac_interrupt(struct kvm_vcpu *vcpu, ulong fac);
    232extern void kvmppc_set_bat(struct kvm_vcpu *vcpu, struct kvmppc_bat *bat,
    233			   bool upper, u32 val);
    234extern void kvmppc_giveup_ext(struct kvm_vcpu *vcpu, ulong msr);
    235extern int kvmppc_emulate_paired_single(struct kvm_vcpu *vcpu);
    236extern kvm_pfn_t kvmppc_gpa_to_pfn(struct kvm_vcpu *vcpu, gpa_t gpa,
    237			bool writing, bool *writable);
    238extern void kvmppc_add_revmap_chain(struct kvm *kvm, struct revmap_entry *rev,
    239			unsigned long *rmap, long pte_index, int realmode);
    240extern void kvmppc_update_dirty_map(const struct kvm_memory_slot *memslot,
    241			unsigned long gfn, unsigned long psize);
    242extern void kvmppc_invalidate_hpte(struct kvm *kvm, __be64 *hptep,
    243			unsigned long pte_index);
    244void kvmppc_clear_ref_hpte(struct kvm *kvm, __be64 *hptep,
    245			unsigned long pte_index);
    246extern void *kvmppc_pin_guest_page(struct kvm *kvm, unsigned long addr,
    247			unsigned long *nb_ret);
    248extern void kvmppc_unpin_guest_page(struct kvm *kvm, void *addr,
    249			unsigned long gpa, bool dirty);
    250extern long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
    251			long pte_index, unsigned long pteh, unsigned long ptel,
    252			pgd_t *pgdir, bool realmode, unsigned long *idx_ret);
    253extern long kvmppc_do_h_remove(struct kvm *kvm, unsigned long flags,
    254			unsigned long pte_index, unsigned long avpn,
    255			unsigned long *hpret);
    256extern long kvmppc_hv_get_dirty_log_hpt(struct kvm *kvm,
    257			struct kvm_memory_slot *memslot, unsigned long *map);
    258extern void kvmppc_harvest_vpa_dirty(struct kvmppc_vpa *vpa,
    259			struct kvm_memory_slot *memslot,
    260			unsigned long *map);
    261extern unsigned long kvmppc_filter_lpcr_hv(struct kvm *kvm,
    262			unsigned long lpcr);
    263extern void kvmppc_update_lpcr(struct kvm *kvm, unsigned long lpcr,
    264			unsigned long mask);
    265extern void kvmppc_set_fscr(struct kvm_vcpu *vcpu, u64 fscr);
    266
    267extern int kvmhv_p9_tm_emulation_early(struct kvm_vcpu *vcpu);
    268extern int kvmhv_p9_tm_emulation(struct kvm_vcpu *vcpu);
    269extern void kvmhv_emulate_tm_rollback(struct kvm_vcpu *vcpu);
    270
    271extern void kvmppc_entry_trampoline(void);
    272extern void kvmppc_hv_entry_trampoline(void);
    273extern u32 kvmppc_alignment_dsisr(struct kvm_vcpu *vcpu, unsigned int inst);
    274extern ulong kvmppc_alignment_dar(struct kvm_vcpu *vcpu, unsigned int inst);
    275extern int kvmppc_h_pr(struct kvm_vcpu *vcpu, unsigned long cmd);
    276extern void kvmppc_pr_init_default_hcalls(struct kvm *kvm);
    277extern int kvmppc_hcall_impl_pr(unsigned long cmd);
    278extern int kvmppc_hcall_impl_hv_realmode(unsigned long cmd);
    279extern void kvmppc_copy_to_svcpu(struct kvm_vcpu *vcpu);
    280extern void kvmppc_copy_from_svcpu(struct kvm_vcpu *vcpu);
    281
    282long kvmppc_read_intr(void);
    283void kvmppc_bad_interrupt(struct pt_regs *regs);
    284void kvmhv_p9_set_lpcr(struct kvm_split_mode *sip);
    285void kvmhv_p9_restore_lpcr(struct kvm_split_mode *sip);
    286void kvmppc_set_msr_hv(struct kvm_vcpu *vcpu, u64 msr);
    287void kvmppc_inject_interrupt_hv(struct kvm_vcpu *vcpu, int vec, u64 srr1_flags);
    288
    289#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
    290void kvmppc_save_tm_pr(struct kvm_vcpu *vcpu);
    291void kvmppc_restore_tm_pr(struct kvm_vcpu *vcpu);
    292void kvmppc_save_tm_sprs(struct kvm_vcpu *vcpu);
    293void kvmppc_restore_tm_sprs(struct kvm_vcpu *vcpu);
    294#else
    295static inline void kvmppc_save_tm_pr(struct kvm_vcpu *vcpu) {}
    296static inline void kvmppc_restore_tm_pr(struct kvm_vcpu *vcpu) {}
    297static inline void kvmppc_save_tm_sprs(struct kvm_vcpu *vcpu) {}
    298static inline void kvmppc_restore_tm_sprs(struct kvm_vcpu *vcpu) {}
    299#endif
    300
    301long kvmhv_nested_init(void);
    302void kvmhv_nested_exit(void);
    303void kvmhv_vm_nested_init(struct kvm *kvm);
    304long kvmhv_set_partition_table(struct kvm_vcpu *vcpu);
    305long kvmhv_copy_tofrom_guest_nested(struct kvm_vcpu *vcpu);
    306void kvmhv_set_ptbl_entry(unsigned int lpid, u64 dw0, u64 dw1);
    307void kvmhv_release_all_nested(struct kvm *kvm);
    308long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu);
    309long kvmhv_do_nested_tlbie(struct kvm_vcpu *vcpu);
    310long do_h_rpt_invalidate_pat(struct kvm_vcpu *vcpu, unsigned long lpid,
    311			     unsigned long type, unsigned long pg_sizes,
    312			     unsigned long start, unsigned long end);
    313int kvmhv_run_single_vcpu(struct kvm_vcpu *vcpu,
    314			  u64 time_limit, unsigned long lpcr);
    315void kvmhv_save_hv_regs(struct kvm_vcpu *vcpu, struct hv_guest_state *hr);
    316void kvmhv_restore_hv_return_state(struct kvm_vcpu *vcpu,
    317				   struct hv_guest_state *hr);
    318long int kvmhv_nested_page_fault(struct kvm_vcpu *vcpu);
    319
    320void kvmppc_giveup_fac(struct kvm_vcpu *vcpu, ulong fac);
    321
    322extern int kvm_irq_bypass;
    323
    324static inline struct kvmppc_vcpu_book3s *to_book3s(struct kvm_vcpu *vcpu)
    325{
    326	return vcpu->arch.book3s;
    327}
    328
    329/* Also add subarch specific defines */
    330
    331#ifdef CONFIG_KVM_BOOK3S_32_HANDLER
    332#include <asm/kvm_book3s_32.h>
    333#endif
    334#ifdef CONFIG_KVM_BOOK3S_64_HANDLER
    335#include <asm/kvm_book3s_64.h>
    336#endif
    337
    338static inline void kvmppc_set_gpr(struct kvm_vcpu *vcpu, int num, ulong val)
    339{
    340	vcpu->arch.regs.gpr[num] = val;
    341}
    342
    343static inline ulong kvmppc_get_gpr(struct kvm_vcpu *vcpu, int num)
    344{
    345	return vcpu->arch.regs.gpr[num];
    346}
    347
    348static inline void kvmppc_set_cr(struct kvm_vcpu *vcpu, u32 val)
    349{
    350	vcpu->arch.regs.ccr = val;
    351}
    352
    353static inline u32 kvmppc_get_cr(struct kvm_vcpu *vcpu)
    354{
    355	return vcpu->arch.regs.ccr;
    356}
    357
    358static inline void kvmppc_set_xer(struct kvm_vcpu *vcpu, ulong val)
    359{
    360	vcpu->arch.regs.xer = val;
    361}
    362
    363static inline ulong kvmppc_get_xer(struct kvm_vcpu *vcpu)
    364{
    365	return vcpu->arch.regs.xer;
    366}
    367
    368static inline void kvmppc_set_ctr(struct kvm_vcpu *vcpu, ulong val)
    369{
    370	vcpu->arch.regs.ctr = val;
    371}
    372
    373static inline ulong kvmppc_get_ctr(struct kvm_vcpu *vcpu)
    374{
    375	return vcpu->arch.regs.ctr;
    376}
    377
    378static inline void kvmppc_set_lr(struct kvm_vcpu *vcpu, ulong val)
    379{
    380	vcpu->arch.regs.link = val;
    381}
    382
    383static inline ulong kvmppc_get_lr(struct kvm_vcpu *vcpu)
    384{
    385	return vcpu->arch.regs.link;
    386}
    387
    388static inline void kvmppc_set_pc(struct kvm_vcpu *vcpu, ulong val)
    389{
    390	vcpu->arch.regs.nip = val;
    391}
    392
    393static inline ulong kvmppc_get_pc(struct kvm_vcpu *vcpu)
    394{
    395	return vcpu->arch.regs.nip;
    396}
    397
    398static inline u64 kvmppc_get_msr(struct kvm_vcpu *vcpu);
    399static inline bool kvmppc_need_byteswap(struct kvm_vcpu *vcpu)
    400{
    401	return (kvmppc_get_msr(vcpu) & MSR_LE) != (MSR_KERNEL & MSR_LE);
    402}
    403
    404static inline ulong kvmppc_get_fault_dar(struct kvm_vcpu *vcpu)
    405{
    406	return vcpu->arch.fault_dar;
    407}
    408
    409/* Expiry time of vcpu DEC relative to host TB */
    410static inline u64 kvmppc_dec_expires_host_tb(struct kvm_vcpu *vcpu)
    411{
    412	return vcpu->arch.dec_expires - vcpu->arch.vcore->tb_offset;
    413}
    414
    415static inline bool is_kvmppc_resume_guest(int r)
    416{
    417	return (r == RESUME_GUEST || r == RESUME_GUEST_NV);
    418}
    419
    420static inline bool is_kvmppc_hv_enabled(struct kvm *kvm);
    421static inline bool kvmppc_supports_magic_page(struct kvm_vcpu *vcpu)
    422{
    423	/* Only PR KVM supports the magic page */
    424	return !is_kvmppc_hv_enabled(vcpu->kvm);
    425}
    426
    427extern int kvmppc_h_logical_ci_load(struct kvm_vcpu *vcpu);
    428extern int kvmppc_h_logical_ci_store(struct kvm_vcpu *vcpu);
    429
    430/* Magic register values loaded into r3 and r4 before the 'sc' assembly
    431 * instruction for the OSI hypercalls */
    432#define OSI_SC_MAGIC_R3			0x113724FA
    433#define OSI_SC_MAGIC_R4			0x77810F9B
    434
    435#define INS_DCBZ			0x7c0007ec
    436/* TO = 31 for unconditional trap */
    437#define INS_TW				0x7fe00008
    438
    439#define SPLIT_HACK_MASK			0xff000000
    440#define SPLIT_HACK_OFFS			0xfb000000
    441
    442/*
    443 * This packs a VCPU ID from the [0..KVM_MAX_VCPU_IDS) space down to the
    444 * [0..KVM_MAX_VCPUS) space, using knowledge of the guest's core stride
    445 * (but not its actual threading mode, which is not available) to avoid
    446 * collisions.
    447 *
    448 * The implementation leaves VCPU IDs from the range [0..KVM_MAX_VCPUS) (block
    449 * 0) unchanged: if the guest is filling each VCORE completely then it will be
    450 * using consecutive IDs and it will fill the space without any packing.
    451 *
    452 * For higher VCPU IDs, the packed ID is based on the VCPU ID modulo
    453 * KVM_MAX_VCPUS (effectively masking off the top bits) and then an offset is
    454 * added to avoid collisions.
    455 *
    456 * VCPU IDs in the range [KVM_MAX_VCPUS..(KVM_MAX_VCPUS*2)) (block 1) are only
    457 * possible if the guest is leaving at least 1/2 of each VCORE empty, so IDs
    458 * can be safely packed into the second half of each VCORE by adding an offset
    459 * of (stride / 2).
    460 *
    461 * Similarly, if VCPU IDs in the range [(KVM_MAX_VCPUS*2)..(KVM_MAX_VCPUS*4))
    462 * (blocks 2 and 3) are seen, the guest must be leaving at least 3/4 of each
    463 * VCORE empty so packed IDs can be offset by (stride / 4) and (stride * 3 / 4).
    464 *
    465 * Finally, VCPU IDs from blocks 5..7 will only be seen if the guest is using a
    466 * stride of 8 and 1 thread per core so the remaining offsets of 1, 5, 3 and 7
    467 * must be free to use.
    468 *
    469 * (The offsets for each block are stored in block_offsets[], indexed by the
    470 * block number if the stride is 8. For cases where the guest's stride is less
    471 * than 8, we can re-use the block_offsets array by multiplying the block
    472 * number by (MAX_SMT_THREADS / stride) to reach the correct entry.)
    473 */
    474static inline u32 kvmppc_pack_vcpu_id(struct kvm *kvm, u32 id)
    475{
    476	const int block_offsets[MAX_SMT_THREADS] = {0, 4, 2, 6, 1, 5, 3, 7};
    477	int stride = kvm->arch.emul_smt_mode;
    478	int block = (id / KVM_MAX_VCPUS) * (MAX_SMT_THREADS / stride);
    479	u32 packed_id;
    480
    481	if (WARN_ONCE(block >= MAX_SMT_THREADS, "VCPU ID too large to pack"))
    482		return 0;
    483	packed_id = (id % KVM_MAX_VCPUS) + block_offsets[block];
    484	if (WARN_ONCE(packed_id >= KVM_MAX_VCPUS, "VCPU ID packing failed"))
    485		return 0;
    486	return packed_id;
    487}
    488
    489#endif /* __ASM_KVM_BOOK3S_H__ */