path: root/arch/arm/kvm/mmu.c

/*
 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
 * Author: Christoffer Dall <c.dall@virtualopensystems.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2, as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include <linux/mman.h>
#include <linux/kvm_host.h>
#include <linux/io.h>
#include <linux/hugetlb.h>
#include <trace/events/kvm.h>
#include <asm/pgalloc.h>
#include <asm/cacheflush.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_mmu.h>
#include <asm/kvm_mmio.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_emulate.h>

#include "trace.h"

extern char  __hyp_idmap_text_start[], __hyp_idmap_text_end[];

static pgd_t *boot_hyp_pgd;
static pgd_t *hyp_pgd;
static DEFINE_MUTEX(kvm_hyp_pgd_mutex);

static void *init_bounce_page;
static unsigned long hyp_idmap_start;
static unsigned long hyp_idmap_end;
static phys_addr_t hyp_idmap_vector;

#define kvm_pmd_huge(_x)	(pmd_huge(_x) || pmd_trans_huge(_x))

static void kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
{
	/*
	 * This function also gets called when dealing with HYP page
	 * tables. As HYP doesn't have an associated struct kvm (and
	 * the HYP page tables are fairly static), we don't do
	 * anything there.
	 */
	if (kvm)
		kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, kvm, ipa);
}

static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
				  int min, int max)
{
	void *page;

	BUG_ON(max > KVM_NR_MEM_OBJS);
	if (cache->nobjs >= min)
		return 0;
	while (cache->nobjs < max) {
		page = (void *)__get_free_page(PGALLOC_GFP);
		if (!page)
			return -ENOMEM;
		cache->objects[cache->nobjs++] = page;
	}
	return 0;
}

static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
{
	while (mc->nobjs)
		free_page((unsigned long)mc->objects[--mc->nobjs]);
}

static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
{
	void *p;

	BUG_ON(!mc || !mc->nobjs);
	p = mc->objects[--mc->nobjs];
	return p;
}

static bool page_empty(void *ptr)
{
	struct page *ptr_page = virt_to_page(ptr);
	return page_count(ptr_page) == 1;
}

static void clear_pud_entry(struct kvm *kvm, pud_t *pud, phys_addr_t addr)
{
	if (pud_huge(*pud)) {
		pud_clear(pud);
		kvm_tlb_flush_vmid_ipa(kvm, addr);
	} else {
		pmd_t *pmd_table = pmd_offset(pud, 0);
		pud_clear(pud);
		kvm_tlb_flush_vmid_ipa(kvm, addr);
		pmd_free(NULL, pmd_table);
	}
	put_page(virt_to_page(pud));
}

static void clear_pmd_entry(struct kvm *kvm, pmd_t *pmd, phys_addr_t addr)
{
	if (kvm_pmd_huge(*pmd)) {
		pmd_clear(pmd);
		kvm_tlb_flush_vmid_ipa(kvm, addr);
	} else {
		pte_t *pte_table = pte_offset_kernel(pmd, 0);
		pmd_clear(pmd);
		kvm_tlb_flush_vmid_ipa(kvm, addr);
		pte_free_kernel(NULL, pte_table);
	}
	put_page(virt_to_page(pmd));
}

static void clear_pte_entry(struct kvm *kvm, pte_t *pte, phys_addr_t addr)
{
	if (pte_present(*pte)) {
		kvm_set_pte(pte, __pte(0));
		put_page(virt_to_page(pte));
		kvm_tlb_flush_vmid_ipa(kvm, addr);
	}
}

static void unmap_range(struct kvm *kvm, pgd_t *pgdp,
			unsigned long long start, u64 size)
{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;
	unsigned long long addr = start, end = start + size;
	u64 next;

	while (addr < end) {
		pgd = pgdp + pgd_index(addr);
		pud = pud_offset(pgd, addr);
		if (pud_none(*pud)) {
			addr = pud_addr_end(addr, end);
			continue;
		}

		if (pud_huge(*pud)) {
			/*
			 * If we are dealing with a huge pud, just clear it and
			 * move on.
			 */
			clear_pud_entry