KVM: s390: KVM-specific bitfields and helper functions (5a74e3d9) · Commits · git / linux-net

arch/s390/kvm/dat.h

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		/* SPDX-License-Identifier: GPL-2.0 */
		/*
		* KVM guest address space mapping code
		*
		* Copyright IBM Corp. 2024, 2025
		* Author(s): Claudio Imbrenda <imbrenda@linux.ibm.com>
		*/

		#ifndef __KVM_S390_DAT_H
		#define __KVM_S390_DAT_H

		#include <linux/radix-tree.h>
		#include <linux/refcount.h>
		#include <linux/io.h>
		#include <linux/kvm_types.h>
		#include <linux/pgalloc.h>
		#include <asm/tlbflush.h>
		#include <asm/dat-bits.h>

		#define _ASCE(x) ((union asce) { .val = (x), })
		#define NULL_ASCE _ASCE(0)

		enum {
		_DAT_TOKEN_NONE = 0,
		_DAT_TOKEN_PIC,
		};

		#define _CRSTE_TOK(l, t, p) ((union crste) { \
		.tok.i = 1, \
		.tok.tt = (l), \
		.tok.type = (t), \
		.tok.par = (p) \
		})
		#define _CRSTE_PIC(l, p) _CRSTE_TOK(l, _DAT_TOKEN_PIC, p)

		#define _CRSTE_HOLE(l) _CRSTE_PIC(l, PGM_ADDRESSING)
		#define _CRSTE_EMPTY(l) _CRSTE_TOK(l, _DAT_TOKEN_NONE, 0)

		#define _PMD_EMPTY _CRSTE_EMPTY(TABLE_TYPE_SEGMENT)

		#define _PTE_TOK(t, p) ((union pte) { .tok.i = 1, .tok.type = (t), .tok.par = (p) })
		#define _PTE_EMPTY _PTE_TOK(_DAT_TOKEN_NONE, 0)

		/* This fake table type is used for page table walks (both for normal page tables and vSIE) */
		#define TABLE_TYPE_PAGE_TABLE -1

		enum dat_walk_flags {
		DAT_WALK_CONTINUE = 0x20,
		DAT_WALK_IGN_HOLES = 0x10,
		DAT_WALK_SPLIT = 0x08,
		DAT_WALK_ALLOC = 0x04,
		DAT_WALK_ANY = 0x02,
		DAT_WALK_LEAF = 0x01,
		DAT_WALK_DEFAULT = 0
		};

		#define DAT_WALK_SPLIT_ALLOC (DAT_WALK_SPLIT \| DAT_WALK_ALLOC)
		#define DAT_WALK_ALLOC_CONTINUE (DAT_WALK_CONTINUE \| DAT_WALK_ALLOC)
		#define DAT_WALK_LEAF_ALLOC (DAT_WALK_LEAF \| DAT_WALK_ALLOC)

		union pte {
		unsigned long val;
		union page_table_entry h;
		struct {
		unsigned long :56; /* Hardware bits */
		unsigned long u : 1; /* Page unused */
		unsigned long s : 1; /* Special */
		unsigned long w : 1; /* Writable */
		unsigned long r : 1; /* Readable */
		unsigned long d : 1; /* Dirty */
		unsigned long y : 1; /* Young */
		unsigned long sd: 1; /* Soft dirty */
		unsigned long pr: 1; /* Present */
		} s;
		struct {
		unsigned char hwbytes[7];
		unsigned char swbyte;
		};
		union {
		struct {
		unsigned long type :16; /* Token type */
		unsigned long par :16; /* Token parameter */
		unsigned long :20;
		unsigned long : 1; /* Must be 0 */
		unsigned long i : 1; /* Must be 1 */
		unsigned long : 2;
		unsigned long : 7;
		unsigned long pr : 1; /* Must be 0 */
		};
		struct {
		unsigned long token:32; /* Token and parameter */
		unsigned long :32;
		};
		} tok;
		};

		/* Soft dirty, needed as macro for atomic operations on ptes */
		#define _PAGE_SD 0x002

		/* Needed as macro to perform atomic operations */
		#define PGSTE_CMMA_D_BIT 0x0000000000008000UL /* CMMA dirty soft-bit */

		enum pgste_gps_usage {
		PGSTE_GPS_USAGE_STABLE = 0,
		PGSTE_GPS_USAGE_UNUSED,
		PGSTE_GPS_USAGE_POT_VOLATILE,
		PGSTE_GPS_USAGE_VOLATILE,
		};

		union pgste {
		unsigned long val;
		struct {
		unsigned long acc : 4;
		unsigned long fp : 1;
		unsigned long : 3;
		unsigned long pcl : 1;
		unsigned long hr : 1;
		unsigned long hc : 1;
		unsigned long : 2;
		unsigned long gr : 1;
		unsigned long gc : 1;
		unsigned long : 1;
		unsigned long :16; /* val16 */
		unsigned long zero : 1;
		unsigned long nodat : 1;
		unsigned long : 4;
		unsigned long usage : 2;
		unsigned long : 8;
		unsigned long cmma_d : 1; /* Dirty flag for CMMA bits */
		unsigned long prefix_notif : 1; /* Guest prefix invalidation notification */
		unsigned long vsie_notif : 1; /* Referenced in a shadow table */
		unsigned long : 5;
		unsigned long : 8;
		};
		struct {
		unsigned short hwbytes0;
		unsigned short val16; /* Used to store chunked values, see dat_{s,g}et_ptval() */
		unsigned short hwbytes4;
		unsigned char flags; /* Maps to the software bits */
		unsigned char hwbyte7;
		} __packed;
		};

		union pmd {
		unsigned long val;
		union segment_table_entry h;
		struct {
		struct {
		unsigned long :44; /* HW */
		unsigned long : 3; /* Unused */
		unsigned long : 1; /* HW */
		unsigned long w : 1; /* Writable soft-bit */
		unsigned long r : 1; /* Readable soft-bit */
		unsigned long d : 1; /* Dirty */
		unsigned long y : 1; /* Young */
		unsigned long prefix_notif : 1; /* Guest prefix invalidation notification */
		unsigned long : 3; /* HW */
		unsigned long vsie_notif : 1; /* Referenced in a shadow table */
		unsigned long : 1; /* Unused */
		unsigned long : 4; /* HW */
		unsigned long sd : 1; /* Soft-Dirty */
		unsigned long pr : 1; /* Present */
		} fc1;
		} s;
		};

		union pud {
		unsigned long val;
		union region3_table_entry h;
		struct {
		struct {
		unsigned long :33; /* HW */
		unsigned long :14; /* Unused */
		unsigned long : 1; /* HW */
		unsigned long w : 1; /* Writable soft-bit */
		unsigned long r : 1; /* Readable soft-bit */
		unsigned long d : 1; /* Dirty */
		unsigned long y : 1; /* Young */
		unsigned long prefix_notif : 1; /* Guest prefix invalidation notification */
		unsigned long : 3; /* HW */
		unsigned long vsie_notif : 1; /* Referenced in a shadow table */
		unsigned long : 1; /* Unused */
		unsigned long : 4; /* HW */
		unsigned long sd : 1; /* Soft-Dirty */
		unsigned long pr : 1; /* Present */
		} fc1;
		} s;
		};

		union p4d {
		unsigned long val;
		union region2_table_entry h;
		};

		union pgd {
		unsigned long val;
		union region1_table_entry h;
		};

		union crste {
		unsigned long val;
		union {
		struct {
		unsigned long :52;
		unsigned long : 1;
		unsigned long fc: 1;
		unsigned long p : 1;
		unsigned long : 1;
		unsigned long : 2;
		unsigned long i : 1;
		unsigned long : 1;
		unsigned long tt: 2;
		unsigned long : 2;
		};
		struct {
		unsigned long to:52;
		unsigned long : 1;
		unsigned long fc: 1;
		unsigned long p : 1;
		unsigned long : 1;
		unsigned long tf: 2;
		unsigned long i : 1;
		unsigned long : 1;
		unsigned long tt: 2;
		unsigned long tl: 2;
		} fc0;
		struct {
		unsigned long :47;
		unsigned long av : 1; /* ACCF-Validity Control */
		unsigned long acc: 4; /* Access-Control Bits */
		unsigned long f : 1; /* Fetch-Protection Bit */
		unsigned long fc : 1; /* Format-Control */
		unsigned long p : 1; /* DAT-Protection Bit */
		unsigned long iep: 1; /* Instruction-Execution-Protection */
		unsigned long : 2;
		unsigned long i : 1; /* Segment-Invalid Bit */
		unsigned long cs : 1; /* Common-Segment Bit */
		unsigned long tt : 2; /* Table-Type Bits */
		unsigned long : 2;
		} fc1;
		} h;
		struct {
		struct {
		unsigned long :47;
		unsigned long : 1; /* HW (should be 0) */
		unsigned long w : 1; /* Writable */
		unsigned long r : 1; /* Readable */
		unsigned long d : 1; /* Dirty */
		unsigned long y : 1; /* Young */
		unsigned long prefix_notif : 1; /* Guest prefix invalidation notification */
		unsigned long : 3; /* HW */
		unsigned long vsie_notif : 1; /* Referenced in a shadow table */
		unsigned long : 1;
		unsigned long : 4; /* HW */
		unsigned long sd : 1; /* Soft-Dirty */
		unsigned long pr : 1; /* Present */
		} fc1;
		} s;
		union {
		struct {
		unsigned long type :16; /* Token type */
		unsigned long par :16; /* Token parameter */
		unsigned long :26;
		unsigned long i : 1; /* Must be 1 */
		unsigned long : 1;
		unsigned long tt : 2;
		unsigned long : 1;
		unsigned long pr : 1; /* Must be 0 */
		};
		struct {
		unsigned long token:32; /* Token and parameter */
		unsigned long :32;
		};
		} tok;
		union pmd pmd;
		union pud pud;
		union p4d p4d;
		union pgd pgd;
		};

		union skey {
		unsigned char skey;
		struct {
		unsigned char acc :4;
		unsigned char fp :1;
		unsigned char r :1;
		unsigned char c :1;
		unsigned char zero:1;
		};
		};

		static_assert(sizeof(union pgste) == sizeof(unsigned long));
		static_assert(sizeof(union pte) == sizeof(unsigned long));
		static_assert(sizeof(union pmd) == sizeof(unsigned long));
		static_assert(sizeof(union pud) == sizeof(unsigned long));
		static_assert(sizeof(union p4d) == sizeof(unsigned long));
		static_assert(sizeof(union pgd) == sizeof(unsigned long));
		static_assert(sizeof(union crste) == sizeof(unsigned long));
		static_assert(sizeof(union skey) == sizeof(char));

		struct segment_table {
		union pmd pmds[_CRST_ENTRIES];
		};

		struct region3_table {
		union pud puds[_CRST_ENTRIES];
		};

		struct region2_table {
		union p4d p4ds[_CRST_ENTRIES];
		};

		struct region1_table {
		union pgd pgds[_CRST_ENTRIES];
		};

		struct crst_table {
		union {
		union crste crstes[_CRST_ENTRIES];
		struct segment_table segment;
		struct region3_table region3;
		struct region2_table region2;
		struct region1_table region1;
		};
		};

		struct page_table {
		union pte ptes[_PAGE_ENTRIES];
		union pgste pgstes[_PAGE_ENTRIES];
		};

		static_assert(sizeof(struct crst_table) == _CRST_TABLE_SIZE);
		static_assert(sizeof(struct page_table) == PAGE_SIZE);

		/**
		* _pte() - Useful constructor for union pte
		* @pfn: the pfn this pte should point to.
		* @writable: whether the pte should be writable.
		* @dirty: whether the pte should be dirty.
		* @special: whether the pte should be marked as special
		*
		* The pte is also marked as young and present. If the pte is marked as dirty,
		* it gets marked as soft-dirty too. If the pte is not dirty, the hardware
		* protect bit is set (independently of the write softbit); this way proper
		* dirty tracking can be performed.
		*
		* Return: a union pte value.
		*/
		static inline union pte _pte(kvm_pfn_t pfn, bool writable, bool dirty, bool special)
		{
		union pte res = { .val = PFN_PHYS(pfn) };

		res.h.p = !dirty;
		res.s.y = 1;
		res.s.pr = 1;
		res.s.w = writable;
		res.s.d = dirty;
		res.s.sd = dirty;
		res.s.s = special;
		return res;
		}

		static inline union crste _crste_fc0(kvm_pfn_t pfn, int tt)
		{
		union crste res = { .val = PFN_PHYS(pfn) };

		res.h.tt = tt;
		res.h.fc0.tl = _REGION_ENTRY_LENGTH;
		res.h.fc0.tf = 0;
		return res;
		}

		/**
		* _crste() - Useful constructor for union crste with FC=1
		* @pfn: the pfn this pte should point to.
		* @tt: the table type
		* @writable: whether the pte should be writable.
		* @dirty: whether the pte should be dirty.
		*
		* The crste is also marked as young and present. If the crste is marked as
		* dirty, it gets marked as soft-dirty too. If the crste is not dirty, the
		* hardware protect bit is set (independently of the write softbit); this way
		* proper dirty tracking can be performed.
		*
		* Return: a union crste value.
		*/
		static inline union crste _crste_fc1(kvm_pfn_t pfn, int tt, bool writable, bool dirty)
		{
		union crste res = { .val = PFN_PHYS(pfn) & _SEGMENT_MASK };

		res.h.tt = tt;
		res.h.p = !dirty;
		res.h.fc = 1;
		res.s.fc1.y = 1;
		res.s.fc1.pr = 1;
		res.s.fc1.w = writable;
		res.s.fc1.d = dirty;
		res.s.fc1.sd = dirty;
		return res;
		}

		/**
		* struct vsie_rmap - reverse mapping for shadow page table entries
		* @next: pointer to next rmap in the list
		* @r_gfn: virtual rmap address in the shadow guest address space
		*/
		struct vsie_rmap {
		struct vsie_rmap *next;
		union {
		unsigned long val;
		struct {
		long level: 8;
		unsigned long : 4;
		unsigned long r_gfn:52;
		};
		};
		};

		static_assert(sizeof(struct vsie_rmap) == 2 * sizeof(long));

		static inline struct crst_table crste_table_start(union crste crstep)
		{
		return (struct crst_table *)ALIGN_DOWN((unsigned long)crstep, _CRST_TABLE_SIZE);
		}

		static inline struct page_table pte_table_start(union pte ptep)
		{
		return (struct page_table *)ALIGN_DOWN((unsigned long)ptep, _PAGE_TABLE_SIZE);
		}

		static inline bool crdte_crste(union crste *crstep, union crste old, union crste new, gfn_t gfn,
		union asce asce)
		{
		unsigned long dtt = 0x10 \| new.h.tt << 2;
		void *table = crste_table_start(crstep);

		return crdte(old.val, new.val, table, dtt, gfn_to_gpa(gfn), asce.val);
		}

		/**
		* idte_crste() - invalidate a crste entry using idte
		* @crstep: pointer to the crste to be invalidated
		* @gfn: a gfn mapped by the crste
		* @opt: options for the idte instruction
		* @asce: the asce
		* @local: whether the operation is cpu-local
		*/
		static __always_inline void idte_crste(union crste *crstep, gfn_t gfn, unsigned long opt,
		union asce asce, int local)
		{
		unsigned long table_origin = __pa(crste_table_start(crstep));
		unsigned long gaddr = gfn_to_gpa(gfn) & HPAGE_MASK;

		if (__builtin_constant_p(opt) && opt == 0) {
		/* flush without guest asce */
		asm volatile("idte %[table_origin],0,%[gaddr],%[local]"
		: "+m" (*crstep)
		: [table_origin] "a" (table_origin), [gaddr] "a" (gaddr),
		[local] "i" (local)
		: "cc");
		} else {
		/* flush with guest asce */
		asm volatile("idte %[table_origin],%[asce],%[gaddr_opt],%[local]"
		: "+m" (*crstep)
		: [table_origin] "a" (table_origin), [gaddr_opt] "a" (gaddr \| opt),
		[asce] "a" (asce.val), [local] "i" (local)
		: "cc");
		}
		}

		static inline void dat_init_pgstes(struct page_table *pt, unsigned long val)
		{
		memset64((void *)pt->pgstes, val, PTRS_PER_PTE);
		}

		static inline void dat_init_page_table(struct page_table *pt, unsigned long ptes,
		unsigned long pgstes)
		{
		memset64((void *)pt->ptes, ptes, PTRS_PER_PTE);
		dat_init_pgstes(pt, pgstes);
		}

		static inline gfn_t asce_end(union asce asce)
		{
		return 1ULL << ((asce.dt + 1) * 11 + _SEGMENT_SHIFT - PAGE_SHIFT);
		}

		#define _CRSTE(x) ((union crste) { .val = _Generic((x), \
		union pgd : (x).val, \
		union p4d : (x).val, \
		union pud : (x).val, \
		union pmd : (x).val, \
		union crste : (x).val)})

		#define _CRSTEP(x) ((union crste )_Generic(((x)), \
		union pgd : (x), \
		union p4d : (x), \
		union pud : (x), \
		union pmd : (x), \
		union crste : (x)))

		#define _CRSTP(x) ((struct crst_table )_Generic(((x)), \
		struct crst_table : (x), \
		struct segment_table : (x), \
		struct region3_table : (x), \
		struct region2_table : (x), \
		struct region1_table : (x)))

		static inline bool asce_contains_gfn(union asce asce, gfn_t gfn)
		{
		return gfn < asce_end(asce);
		}

		static inline bool is_pmd(union crste crste)
		{
		return crste.h.tt == TABLE_TYPE_SEGMENT;
		}

		static inline bool is_pud(union crste crste)
		{
		return crste.h.tt == TABLE_TYPE_REGION3;
		}

		static inline bool is_p4d(union crste crste)
		{
		return crste.h.tt == TABLE_TYPE_REGION2;
		}

		static inline bool is_pgd(union crste crste)
		{
		return crste.h.tt == TABLE_TYPE_REGION1;
		}

		static inline phys_addr_t pmd_origin_large(union pmd pmd)
		{
		return pmd.val & _SEGMENT_ENTRY_ORIGIN_LARGE;
		}

		static inline phys_addr_t pud_origin_large(union pud pud)
		{
		return pud.val & _REGION3_ENTRY_ORIGIN_LARGE;
		}

		/**
		* crste_origin_large() - Return the large frame origin of a large crste
		* @crste: The crste whose origin is to be returned. Should be either a
		* region-3 table entry or a segment table entry, in both cases with
		* FC set to 1 (large pages).
		*
		* Return: The origin of the large frame pointed to by @crste, or -1 if the
		* crste was not large (wrong table type, or FC==0)
		*/
		static inline phys_addr_t crste_origin_large(union crste crste)
		{
		if (unlikely(!crste.h.fc \|\| crste.h.tt > TABLE_TYPE_REGION3))
		return -1;
		if (is_pmd(crste))
		return pmd_origin_large(crste.pmd);
		return pud_origin_large(crste.pud);
		}

		#define crste_origin(x) (_Generic((x), \
		union pmd : (x).val & _SEGMENT_ENTRY_ORIGIN, \
		union pud : (x).val & _REGION_ENTRY_ORIGIN, \
		union p4d : (x).val & _REGION_ENTRY_ORIGIN, \
		union pgd : (x).val & _REGION_ENTRY_ORIGIN))

		static inline unsigned long pte_origin(union pte pte)
		{
		return pte.val & PAGE_MASK;
		}

		static inline bool pmd_prefix(union pmd pmd)
		{
		return pmd.h.fc && pmd.s.fc1.prefix_notif;
		}

		static inline bool pud_prefix(union pud pud)
		{
		return pud.h.fc && pud.s.fc1.prefix_notif;
		}

		static inline bool crste_leaf(union crste crste)
		{
		return (crste.h.tt <= TABLE_TYPE_REGION3) && crste.h.fc;
		}

		static inline bool crste_prefix(union crste crste)
		{
		return crste_leaf(crste) && crste.s.fc1.prefix_notif;
		}

		static inline bool crste_dirty(union crste crste)
		{
		return crste_leaf(crste) && crste.s.fc1.d;
		}

		static inline union pgste pgste_of(union pte pte)
		{
		return (union pgste *)(pte + _PAGE_ENTRIES);
		}

		static inline bool pte_hole(union pte pte)
		{
		return pte.h.i && !pte.tok.pr && pte.tok.type != _DAT_TOKEN_NONE;
		}

		static inline bool _crste_hole(union crste crste)
		{
		return crste.h.i && !crste.tok.pr && crste.tok.type != _DAT_TOKEN_NONE;
		}

		#define crste_hole(x) _crste_hole(_CRSTE(x))

		static inline bool _crste_none(union crste crste)
		{
		return crste.h.i && !crste.tok.pr && crste.tok.type == _DAT_TOKEN_NONE;
		}

		#define crste_none(x) _crste_none(_CRSTE(x))

		static inline phys_addr_t large_pud_to_phys(union pud pud, gfn_t gfn)
		{
		return pud_origin_large(pud) \| (gfn_to_gpa(gfn) & ~_REGION3_MASK);
		}

		static inline phys_addr_t large_pmd_to_phys(union pmd pmd, gfn_t gfn)
		{
		return pmd_origin_large(pmd) \| (gfn_to_gpa(gfn) & ~_SEGMENT_MASK);
		}

		static inline phys_addr_t large_crste_to_phys(union crste crste, gfn_t gfn)
		{
		if (unlikely(!crste.h.fc \|\| crste.h.tt > TABLE_TYPE_REGION3))
		return -1;
		if (is_pmd(crste))
		return large_pmd_to_phys(crste.pmd, gfn);
		return large_pud_to_phys(crste.pud, gfn);
		}

		static inline bool cspg_crste(union crste *crstep, union crste old, union crste new)
		{
		return cspg(&crstep->val, old.val, new.val);
		}

		static inline struct page_table *dereference_pmd(union pmd pmd)
		{
		return phys_to_virt(crste_origin(pmd));
		}

		static inline struct segment_table *dereference_pud(union pud pud)
		{
		return phys_to_virt(crste_origin(pud));
		}

		static inline struct region3_table *dereference_p4d(union p4d p4d)
		{
		return phys_to_virt(crste_origin(p4d));
		}

		static inline struct region2_table *dereference_pgd(union pgd pgd)
		{
		return phys_to_virt(crste_origin(pgd));
		}

		static inline struct crst_table *_dereference_crste(union crste crste)
		{
		if (unlikely(is_pmd(crste)))
		return NULL;
		return phys_to_virt(crste_origin(crste.pud));
		}

		#define dereference_crste(x) (_Generic((x), \
		union pud : _dereference_crste(_CRSTE(x)), \
		union p4d : _dereference_crste(_CRSTE(x)), \
		union pgd : _dereference_crste(_CRSTE(x)), \
		union crste : _dereference_crste(_CRSTE(x))))

		static inline struct crst_table *dereference_asce(union asce asce)
		{
		return phys_to_virt(asce.val & _ASCE_ORIGIN);
		}

		static inline void asce_flush_tlb(union asce asce)
		{
		__tlb_flush_idte(asce.val);
		}

		static inline bool pgste_get_trylock(union pte ptep, union pgste res)
		{
		union pgste *pgstep = pgste_of(ptep);
		union pgste old_pgste;

		if (READ_ONCE(pgstep->val) & PGSTE_PCL_BIT)
		return false;
		old_pgste.val = __atomic64_or_barrier(PGSTE_PCL_BIT, &pgstep->val);
		if (old_pgste.pcl)
		return false;
		old_pgste.pcl = 1;
		*res = old_pgste;
		return true;
		}

		static inline union pgste pgste_get_lock(union pte *ptep)
		{
		union pgste res;

		while (!pgste_get_trylock(ptep, &res))
		cpu_relax();
		return res;
		}

		static inline void pgste_set_unlock(union pte *ptep, union pgste pgste)
		{
		pgste.pcl = 0;
		barrier();
		WRITE_ONCE(*pgste_of(ptep), pgste);
		}

		#endif /* __KVM_S390_DAT_H */