LoongArch: KVM: Implement kvm mmu operations

/* SPDX-License-Identifier: GPL-2.0 */

/*

 * Copyright (C) 2020-2023 Loongson Technology Corporation Limited

 */

#ifndef __ASM_LOONGARCH_KVM_MMU_H__

#define __ASM_LOONGARCH_KVM_MMU_H__

#include <linux/kvm_host.h>

#include <asm/pgalloc.h>

#include <asm/tlb.h>

/*

 * KVM_MMU_CACHE_MIN_PAGES is the number of GPA page table translation levels

 * for which pages need to be cached.

 */

#define KVM_MMU_CACHE_MIN_PAGES	(CONFIG_PGTABLE_LEVELS - 1)

#define _KVM_FLUSH_PGTABLE	0x1

#define _KVM_HAS_PGMASK		0x2

#define kvm_pfn_pte(pfn, prot)	(((pfn) << PFN_PTE_SHIFT) | pgprot_val(prot))

#define kvm_pte_pfn(x)		((phys_addr_t)((x & _PFN_MASK) >> PFN_PTE_SHIFT))

typedef unsigned long kvm_pte_t;

typedef struct kvm_ptw_ctx kvm_ptw_ctx;

typedef int (*kvm_pte_ops)(kvm_pte_t *pte, phys_addr_t addr, kvm_ptw_ctx *ctx);

struct kvm_ptw_ctx {

	kvm_pte_ops     ops;

	unsigned long   flag;

	/* for kvm_arch_mmu_enable_log_dirty_pt_masked use */

	unsigned long   mask;

	unsigned long   gfn;

	/* page walk mmu info */

	unsigned int    level;

	unsigned long   pgtable_shift;

	unsigned long   invalid_entry;

	unsigned long   *invalid_ptes;

	unsigned int    *pte_shifts;

	void		*opaque;

	/* free pte table page list */

	struct list_head list;

};

kvm_pte_t *kvm_pgd_alloc(void);

static inline void kvm_set_pte(kvm_pte_t *ptep, kvm_pte_t val)

{

	WRITE_ONCE(*ptep, val);

}

static inline int kvm_pte_write(kvm_pte_t pte) { return pte & _PAGE_WRITE; }

static inline int kvm_pte_dirty(kvm_pte_t pte) { return pte & _PAGE_DIRTY; }

static inline int kvm_pte_young(kvm_pte_t pte) { return pte & _PAGE_ACCESSED; }

static inline int kvm_pte_huge(kvm_pte_t pte) { return pte & _PAGE_HUGE; }

static inline kvm_pte_t kvm_pte_mkyoung(kvm_pte_t pte)

{

	return pte | _PAGE_ACCESSED;

}

static inline kvm_pte_t kvm_pte_mkold(kvm_pte_t pte)

{

	return pte & ~_PAGE_ACCESSED;

}

static inline kvm_pte_t kvm_pte_mkdirty(kvm_pte_t pte)

{

	return pte | _PAGE_DIRTY;

}

static inline kvm_pte_t kvm_pte_mkclean(kvm_pte_t pte)

{

	return pte & ~_PAGE_DIRTY;

}

static inline kvm_pte_t kvm_pte_mkhuge(kvm_pte_t pte)

{

	return pte | _PAGE_HUGE;

}

static inline kvm_pte_t kvm_pte_mksmall(kvm_pte_t pte)

{

	return pte & ~_PAGE_HUGE;

}

static inline int kvm_need_flush(kvm_ptw_ctx *ctx)

{

	return ctx->flag & _KVM_FLUSH_PGTABLE;

}

static inline kvm_pte_t *kvm_pgtable_offset(kvm_ptw_ctx *ctx, kvm_pte_t *table,

					phys_addr_t addr)

{

	return table + ((addr >> ctx->pgtable_shift) & (PTRS_PER_PTE - 1));

}

static inline phys_addr_t kvm_pgtable_addr_end(kvm_ptw_ctx *ctx,

				phys_addr_t addr, phys_addr_t end)

{

	phys_addr_t boundary, size;

	size = 0x1UL << ctx->pgtable_shift;

	boundary = (addr + size) & ~(size - 1);

	return (boundary - 1 < end - 1) ? boundary : end;

}

static inline int kvm_pte_present(kvm_ptw_ctx *ctx, kvm_pte_t *entry)

{

	if (!ctx || ctx->level == 0)

		return !!(*entry & _PAGE_PRESENT);

	return *entry != ctx->invalid_entry;

}

static inline int kvm_pte_none(kvm_ptw_ctx *ctx, kvm_pte_t *entry)

{

	return *entry == ctx->invalid_entry;

}

static inline void kvm_ptw_enter(kvm_ptw_ctx *ctx)

{

	ctx->level--;

	ctx->pgtable_shift = ctx->pte_shifts[ctx->level];

	ctx->invalid_entry = ctx->invalid_ptes[ctx->level];

}

static inline void kvm_ptw_exit(kvm_ptw_ctx *ctx)

{

	ctx->level++;

	ctx->pgtable_shift = ctx->pte_shifts[ctx->level];

	ctx->invalid_entry = ctx->invalid_ptes[ctx->level];

}

#endif /* __ASM_LOONGARCH_KVM_MMU_H__ */