1 /*
2 * Copyright (C) 2015 - ARM Ltd
3 * Author: Marc Zyngier <marc.zyngier@arm.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program. If not, see <http://www.gnu.org/licenses/>.
16 */
17
18 #include <asm/kvm_hyp.h>
19 #include <asm/kvm_mmu.h>
20 #include <asm/tlbflush.h>
21
__tlb_switch_to_guest_vhe(struct kvm * kvm)22 static void __hyp_text __tlb_switch_to_guest_vhe(struct kvm *kvm)
23 {
24 u64 val;
25
26 /*
27 * With VHE enabled, we have HCR_EL2.{E2H,TGE} = {1,1}, and
28 * most TLB operations target EL2/EL0. In order to affect the
29 * guest TLBs (EL1/EL0), we need to change one of these two
30 * bits. Changing E2H is impossible (goodbye TTBR1_EL2), so
31 * let's flip TGE before executing the TLB operation.
32 */
33 write_sysreg(kvm->arch.vttbr, vttbr_el2);
34 val = read_sysreg(hcr_el2);
35 val &= ~HCR_TGE;
36 write_sysreg(val, hcr_el2);
37 isb();
38 }
39
__tlb_switch_to_guest_nvhe(struct kvm * kvm)40 static void __hyp_text __tlb_switch_to_guest_nvhe(struct kvm *kvm)
41 {
42 write_sysreg(kvm->arch.vttbr, vttbr_el2);
43 isb();
44 }
45
46 static hyp_alternate_select(__tlb_switch_to_guest,
47 __tlb_switch_to_guest_nvhe,
48 __tlb_switch_to_guest_vhe,
49 ARM64_HAS_VIRT_HOST_EXTN);
50
__tlb_switch_to_host_vhe(struct kvm * kvm)51 static void __hyp_text __tlb_switch_to_host_vhe(struct kvm *kvm)
52 {
53 /*
54 * We're done with the TLB operation, let's restore the host's
55 * view of HCR_EL2.
56 */
57 write_sysreg(0, vttbr_el2);
58 write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);
59 }
60
__tlb_switch_to_host_nvhe(struct kvm * kvm)61 static void __hyp_text __tlb_switch_to_host_nvhe(struct kvm *kvm)
62 {
63 write_sysreg(0, vttbr_el2);
64 }
65
66 static hyp_alternate_select(__tlb_switch_to_host,
67 __tlb_switch_to_host_nvhe,
68 __tlb_switch_to_host_vhe,
69 ARM64_HAS_VIRT_HOST_EXTN);
70
__kvm_tlb_flush_vmid_ipa(struct kvm * kvm,phys_addr_t ipa)71 void __hyp_text __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
72 {
73 dsb(ishst);
74
75 /* Switch to requested VMID */
76 kvm = kern_hyp_va(kvm);
77 __tlb_switch_to_guest()(kvm);
78
79 /*
80 * We could do so much better if we had the VA as well.
81 * Instead, we invalidate Stage-2 for this IPA, and the
82 * whole of Stage-1. Weep...
83 */
84 ipa >>= 12;
85 __tlbi(ipas2e1is, ipa);
86
87 /*
88 * We have to ensure completion of the invalidation at Stage-2,
89 * since a table walk on another CPU could refill a TLB with a
90 * complete (S1 + S2) walk based on the old Stage-2 mapping if
91 * the Stage-1 invalidation happened first.
92 */
93 dsb(ish);
94 __tlbi(vmalle1is);
95 dsb(ish);
96 isb();
97
98 /*
99 * If the host is running at EL1 and we have a VPIPT I-cache,
100 * then we must perform I-cache maintenance at EL2 in order for
101 * it to have an effect on the guest. Since the guest cannot hit
102 * I-cache lines allocated with a different VMID, we don't need
103 * to worry about junk out of guest reset (we nuke the I-cache on
104 * VMID rollover), but we do need to be careful when remapping
105 * executable pages for the same guest. This can happen when KSM
106 * takes a CoW fault on an executable page, copies the page into
107 * a page that was previously mapped in the guest and then needs
108 * to invalidate the guest view of the I-cache for that page
109 * from EL1. To solve this, we invalidate the entire I-cache when
110 * unmapping a page from a guest if we have a VPIPT I-cache but
111 * the host is running at EL1. As above, we could do better if
112 * we had the VA.
113 *
114 * The moral of this story is: if you have a VPIPT I-cache, then
115 * you should be running with VHE enabled.
116 */
117 if (!has_vhe() && icache_is_vpipt())
118 __flush_icache_all();
119
120 __tlb_switch_to_host()(kvm);
121 }
122
__kvm_tlb_flush_vmid(struct kvm * kvm)123 void __hyp_text __kvm_tlb_flush_vmid(struct kvm *kvm)
124 {
125 dsb(ishst);
126
127 /* Switch to requested VMID */
128 kvm = kern_hyp_va(kvm);
129 __tlb_switch_to_guest()(kvm);
130
131 __tlbi(vmalls12e1is);
132 dsb(ish);
133 isb();
134
135 __tlb_switch_to_host()(kvm);
136 }
137
__kvm_tlb_flush_local_vmid(struct kvm_vcpu * vcpu)138 void __hyp_text __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu)
139 {
140 struct kvm *kvm = kern_hyp_va(kern_hyp_va(vcpu)->kvm);
141
142 /* Switch to requested VMID */
143 __tlb_switch_to_guest()(kvm);
144
145 __tlbi(vmalle1);
146 dsb(nsh);
147 isb();
148
149 __tlb_switch_to_host()(kvm);
150 }
151
__kvm_flush_vm_context(void)152 void __hyp_text __kvm_flush_vm_context(void)
153 {
154 dsb(ishst);
155 __tlbi(alle1is);
156 asm volatile("ic ialluis" : : );
157 dsb(ish);
158 }
159
