arch/arm64/include/asm/kvm_pkvm.h

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2020 - Google LLC
 * Author: Quentin Perret <qperret@google.com>
 */
#ifndef __ARM64_KVM_PKVM_H__
#define __ARM64_KVM_PKVM_H__

#include <linux/memblock.h>
#include <asm/kvm_pgtable.h>

/* Maximum number of VMs that can co-exist under pKVM. */
#define KVM_MAX_PVMS 255

#define HYP_MEMBLOCK_REGIONS 128

int pkvm_init_host_vm(struct kvm *kvm);
int pkvm_create_hyp_vm(struct kvm *kvm);
void pkvm_destroy_hyp_vm(struct kvm *kvm);

extern struct memblock_region kvm_nvhe_sym(hyp_memory)[];
extern unsigned int kvm_nvhe_sym(hyp_memblock_nr);

static inline unsigned long
hyp_vmemmap_memblock_size(struct memblock_region *reg, size_t vmemmap_entry_size)
{
	unsigned long nr_pages = reg->size >> PAGE_SHIFT;
	unsigned long start, end;

	start = (reg->base >> PAGE_SHIFT) * vmemmap_entry_size;
	end = start + nr_pages * vmemmap_entry_size;
	start = ALIGN_DOWN(start, PAGE_SIZE);
	end = ALIGN(end, PAGE_SIZE);

	return end - start;
}

static inline unsigned long hyp_vmemmap_pages(size_t vmemmap_entry_size)
{
	unsigned long res = 0, i;

	for (i = 0; i < kvm_nvhe_sym(hyp_memblock_nr); i++) {
		res += hyp_vmemmap_memblock_size(&kvm_nvhe_sym(hyp_memory)[i],
						 vmemmap_entry_size);
	}

	return res >> PAGE_SHIFT;
}

static inline unsigned long hyp_vm_table_pages(void)
{
	return PAGE_ALIGN(KVM_MAX_PVMS * sizeof(void *)) >> PAGE_SHIFT;
}

static inline unsigned long __hyp_pgtable_max_pages(unsigned long nr_pages)
{
	unsigned long total = 0, i;

	/* Provision the worst case scenario */
	for (i = 0; i < KVM_PGTABLE_MAX_LEVELS; i++) {
		nr_pages = DIV_ROUND_UP(nr_pages, PTRS_PER_PTE);
		total += nr_pages;
	}

	return total;
}

static inline unsigned long __hyp_pgtable_total_pages(void)
{
	unsigned long res = 0, i;

	/* Cover all of memory with page-granularity */
	for (i = 0; i < kvm_nvhe_sym(hyp_memblock_nr); i++) {
		struct memblock_region *reg = &kvm_nvhe_sym(hyp_memory)[i];
		res += __hyp_pgtable_max_pages(reg->size >> PAGE_SHIFT);
	}

	return res;
}

static inline unsigned long hyp_s1_pgtable_pages(void)
{
	unsigned long res;

	res = __hyp_pgtable_total_pages();

	/* Allow 1 GiB for private mappings */
	res += __hyp_pgtable_max_pages(SZ_1G >> PAGE_SHIFT);

	return res;
}

static inline unsigned long host_s2_pgtable_pages(void)
{
	unsigned long res;

	/*
	 * Include an extra 16 pages to safely upper-bound the worst case of
	 * concatenated pgds.
	 */
	res = __hyp_pgtable_total_pages() + 16;

	/* Allow 1 GiB for MMIO mappings */
	res += __hyp_pgtable_max_pages(SZ_1G >> PAGE_SHIFT);

	return res;
}

#endif	/* __ARM64_KVM_PKVM_H__ */