path: root/arch/s390/kvm/dat.h

/* 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>

/*
 * Base address and length must be sent at the start of each block, therefore
 * it's cheaper to send some clean data, as long as it's less than the size of
 * two longs.
 */
#define KVM_S390_MAX_BIT_DISTANCE (2 * sizeof(void *))
/* For consistency */
#define KVM_S390_CMMA_SIZE_MAX ((u32)KVM_S390_SKEYS_MAX)

#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_USES_SKEYS	= 0x40,
	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;
};

#define _SEGMENT_FR_MASK	(_SEGMENT_MASK >> PAGE_SHIFT)
#define _REGION3_FR_MASK	(_REGION3_MASK >> PAGE_SHIFT)
#define _PAGES_PER_SEGMENT	_PAGE_ENTRIES
#define _PAGES_PER_REGION3	(_PAGES_PER_SEGMENT * _CRST_ENTRIES)

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

/* Needed as macro to perform atomic operations */
#define PGSTE_PCL_BIT		0x0080000000000000UL	/* PCL lock, HW bit */
#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<