linux_dsm_epyc7002/arch/powerpc/kvm/book3s_64_mmu_radix.c

/*
 * 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.
 *
 * Copyright 2016 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
 */

#include <linux/types.h>
#include <linux/string.h>
#include <linux/kvm.h>
#include <linux/kvm_host.h>

#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>

/*
 * Supported radix tree geometry.
 * Like p9, we support either 5 or 9 bits at the first (lowest) level,
 * for a page size of 64k or 4k.
 */
static int p9_supported_radix_bits[4] = { 5, 9, 9, 13 };

int kvmppc_mmu_radix_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
			   struct kvmppc_pte *gpte, bool data, bool iswrite)
{
	struct kvm *kvm = vcpu->kvm;
	u32 pid;
	int ret, level, ps;
	__be64 prte, rpte;
	unsigned long root, pte, index;
	unsigned long rts, bits, offset;
	unsigned long gpa;
	unsigned long proc_tbl_size;

	/* Work out effective PID */
	switch (eaddr >> 62) {
	case 0:
		pid = vcpu->arch.pid;
		break;
	case 3:
		pid = 0;
		break;
	default:
		return -EINVAL;
	}
	proc_tbl_size = 1 << ((kvm->arch.process_table & PRTS_MASK) + 12);
	if (pid * 16 >= proc_tbl_size)
		return -EINVAL;

	/* Read partition table to find root of tree for effective PID */
	ret = kvm_read_guest(kvm, kvm->arch.process_table + pid * 16,
			     &prte, sizeof(prte));
	if (ret)
		return ret;

	root = be64_to_cpu(prte);
	rts = ((root & RTS1_MASK) >> (RTS1_SHIFT - 3)) |
		((root & RTS2_MASK) >> RTS2_SHIFT);
	bits = root & RPDS_MASK;
	root = root & RPDB_MASK;

	/* P9 DD1 interprets RTS (radix tree size) differently */
	offset = rts + 31;
	if (cpu_has_feature(CPU_FTR_POWER9_DD1))
		offset -= 3;

	/* current implementations only support 52-bit space */
	if (offset != 52)
		return -EINVAL;

	for (level = 3; level >= 0; --level) {
		if (level && bits != p9_supported_radix_bits[level])
			return -EINVAL;
		if (level == 0 && !(bits == 5 || bits == 9))
			return -EINVAL;
		offset -= bits;
		index = (eaddr >> offset) & ((1UL << bits) - 1);
		/* check that low bits of page table base are zero */
		if (root & ((1UL << (bits + 3)) - 1))
			return -EINVAL;
		ret = kvm_read_guest(kvm, root + index * 8,
				     &rpte, sizeof(rpte));
		if (ret)
			return ret;
		pte = __be64_to_cpu(rpte);
		if (!(pte & _PAGE_PRESENT))
			return -ENOENT;
		if (pte & _PAGE_PTE)
			break;
		bits = pte & 0x1f;
		root = pte & 0x0fffffffffffff00ul;
	}
	/* need a leaf at lowest level; 512GB pages not supported */
	if (level < 0 || level == 3)
		return -EINVAL;

	/* offset is now log base 2 of the page size */
	gpa = pte & 0x01fffffffffff000ul;
	if (gpa & ((1ul << offset) - 1))
		return -EINVAL;
	gpa += eaddr & ((1ul << offset) - 1);
	for (ps = MMU_PAGE_4K; ps < MMU_PAGE_COUNT; ++ps)
		if (offset == mmu_psize_defs[ps].shift)
			break;
	gpte->page_size = ps;

	gpte->eaddr = eaddr;
	gpte->raddr = gpa;

	/* Work out permissions */
	gpte->may_read = !!(pte & _PAGE_READ);
	gpte->may_write = !!(pte & _PAGE_WRITE);
	gpte->may_execute = !!(pte & _PAGE_EXEC);
	if (kvmppc_get_msr(vcpu) & MSR_PR) {
		if (pte & _PAGE_PRIVILEGED) {
			gpte->may_read = 0;
			gpte->may_write = 0;
			gpte->may_execute = 0;
		}
	} else {
		if (!(pte & _PAGE_PRIVILEGED)) {
			/* Check AMR/IAMR to see if strict mode is in force */
			if (vcpu->arch.amr & (1ul << 62))
				gpte->may_read = 0;
			if (vcpu->arch.amr & (1ul << 63))
				gpte->may_write = 0;
			if (vcpu->arch.iamr & (1ul << 62))
				gpte->may_execute = 0;
		}
	}

	return 0;
}