1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * KVM/MIPS: Binary Patching for privileged instructions, reduces traps.
7 *
8 * Copyright (C) 2012  MIPS Technologies, Inc.  All rights reserved.
9 * Authors: Sanjay Lal <sanjayl@kymasys.com>
10 */
11
12#include <linux/errno.h>
13#include <linux/err.h>
14#include <linux/kvm_host.h>
15#include <linux/module.h>
16#include <linux/vmalloc.h>
17#include <linux/fs.h>
18#include <linux/bootmem.h>
19#include <asm/cacheflush.h>
20
21#include "commpage.h"
22
23#define SYNCI_TEMPLATE  0x041f0000
24#define SYNCI_BASE(x)   (((x) >> 21) & 0x1f)
25#define SYNCI_OFFSET    ((x) & 0xffff)
26
27#define LW_TEMPLATE     0x8c000000
28#define CLEAR_TEMPLATE  0x00000020
29#define SW_TEMPLATE     0xac000000
30
31int kvm_mips_trans_cache_index(uint32_t inst, uint32_t *opc,
32			       struct kvm_vcpu *vcpu)
33{
34	int result = 0;
35	unsigned long kseg0_opc;
36	uint32_t synci_inst = 0x0;
37
38	/* Replace the CACHE instruction, with a NOP */
39	kseg0_opc =
40	    CKSEG0ADDR(kvm_mips_translate_guest_kseg0_to_hpa
41		       (vcpu, (unsigned long) opc));
42	memcpy((void *)kseg0_opc, (void *)&synci_inst, sizeof(uint32_t));
43	local_flush_icache_range(kseg0_opc, kseg0_opc + 32);
44
45	return result;
46}
47
48/*
49 * Address based CACHE instructions are transformed into synci(s). A little
50 * heavy for just D-cache invalidates, but avoids an expensive trap
51 */
52int kvm_mips_trans_cache_va(uint32_t inst, uint32_t *opc,
53			    struct kvm_vcpu *vcpu)
54{
55	int result = 0;
56	unsigned long kseg0_opc;
57	uint32_t synci_inst = SYNCI_TEMPLATE, base, offset;
58
59	base = (inst >> 21) & 0x1f;
60	offset = inst & 0xffff;
61	synci_inst |= (base << 21);
62	synci_inst |= offset;
63
64	kseg0_opc =
65	    CKSEG0ADDR(kvm_mips_translate_guest_kseg0_to_hpa
66		       (vcpu, (unsigned long) opc));
67	memcpy((void *)kseg0_opc, (void *)&synci_inst, sizeof(uint32_t));
68	local_flush_icache_range(kseg0_opc, kseg0_opc + 32);
69
70	return result;
71}
72
73int kvm_mips_trans_mfc0(uint32_t inst, uint32_t *opc, struct kvm_vcpu *vcpu)
74{
75	int32_t rt, rd, sel;
76	uint32_t mfc0_inst;
77	unsigned long kseg0_opc, flags;
78
79	rt = (inst >> 16) & 0x1f;
80	rd = (inst >> 11) & 0x1f;
81	sel = inst & 0x7;
82
83	if ((rd == MIPS_CP0_ERRCTL) && (sel == 0)) {
84		mfc0_inst = CLEAR_TEMPLATE;
85		mfc0_inst |= ((rt & 0x1f) << 16);
86	} else {
87		mfc0_inst = LW_TEMPLATE;
88		mfc0_inst |= ((rt & 0x1f) << 16);
89		mfc0_inst |=
90		    offsetof(struct mips_coproc,
91			     reg[rd][sel]) + offsetof(struct kvm_mips_commpage,
92						      cop0);
93	}
94
95	if (KVM_GUEST_KSEGX(opc) == KVM_GUEST_KSEG0) {
96		kseg0_opc =
97		    CKSEG0ADDR(kvm_mips_translate_guest_kseg0_to_hpa
98			       (vcpu, (unsigned long) opc));
99		memcpy((void *)kseg0_opc, (void *)&mfc0_inst, sizeof(uint32_t));
100		local_flush_icache_range(kseg0_opc, kseg0_opc + 32);
101	} else if (KVM_GUEST_KSEGX((unsigned long) opc) == KVM_GUEST_KSEG23) {
102		local_irq_save(flags);
103		memcpy((void *)opc, (void *)&mfc0_inst, sizeof(uint32_t));
104		local_flush_icache_range((unsigned long)opc,
105					 (unsigned long)opc + 32);
106		local_irq_restore(flags);
107	} else {
108		kvm_err("%s: Invalid address: %p\n", __func__, opc);
109		return -EFAULT;
110	}
111
112	return 0;
113}
114
115int kvm_mips_trans_mtc0(uint32_t inst, uint32_t *opc, struct kvm_vcpu *vcpu)
116{
117	int32_t rt, rd, sel;
118	uint32_t mtc0_inst = SW_TEMPLATE;
119	unsigned long kseg0_opc, flags;
120
121	rt = (inst >> 16) & 0x1f;
122	rd = (inst >> 11) & 0x1f;
123	sel = inst & 0x7;
124
125	mtc0_inst |= ((rt & 0x1f) << 16);
126	mtc0_inst |=
127	    offsetof(struct mips_coproc,
128		     reg[rd][sel]) + offsetof(struct kvm_mips_commpage, cop0);
129
130	if (KVM_GUEST_KSEGX(opc) == KVM_GUEST_KSEG0) {
131		kseg0_opc =
132		    CKSEG0ADDR(kvm_mips_translate_guest_kseg0_to_hpa
133			       (vcpu, (unsigned long) opc));
134		memcpy((void *)kseg0_opc, (void *)&mtc0_inst, sizeof(uint32_t));
135		local_flush_icache_range(kseg0_opc, kseg0_opc + 32);
136	} else if (KVM_GUEST_KSEGX((unsigned long) opc) == KVM_GUEST_KSEG23) {
137		local_irq_save(flags);
138		memcpy((void *)opc, (void *)&mtc0_inst, sizeof(uint32_t));
139		local_flush_icache_range((unsigned long)opc,
140					 (unsigned long)opc + 32);
141		local_irq_restore(flags);
142	} else {
143		kvm_err("%s: Invalid address: %p\n", __func__, opc);
144		return -EFAULT;
145	}
146
147	return 0;
148}
149