1 /*
2  * Copyright (C) 2012-2015 - 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 <linux/compiler.h>
19 #include <linux/irqchip/arm-gic.h>
20 #include <linux/kvm_host.h>
21 #include <linux/swab.h>
22 
23 #include <asm/kvm_emulate.h>
24 #include <asm/kvm_hyp.h>
25 #include <asm/kvm_mmu.h>
26 
27 static bool __hyp_text __is_be(struct kvm_vcpu *vcpu)
28 {
29 	if (vcpu_mode_is_32bit(vcpu))
30 		return !!(read_sysreg_el2(spsr) & PSR_AA32_E_BIT);
31 
32 	return !!(read_sysreg(SCTLR_EL1) & SCTLR_ELx_EE);
33 }
34 
35 /*
36  * __vgic_v2_perform_cpuif_access -- perform a GICV access on behalf of the
37  *				     guest.
38  *
39  * @vcpu: the offending vcpu
40  *
41  * Returns:
42  *  1: GICV access successfully performed
43  *  0: Not a GICV access
44  * -1: Illegal GICV access successfully performed
45  */
46 int __hyp_text __vgic_v2_perform_cpuif_access(struct kvm_vcpu *vcpu)
47 {
48 	struct kvm *kvm = kern_hyp_va(vcpu->kvm);
49 	struct vgic_dist *vgic = &kvm->arch.vgic;
50 	phys_addr_t fault_ipa;
51 	void __iomem *addr;
52 	int rd;
53 
54 	/* Build the full address */
55 	fault_ipa  = kvm_vcpu_get_fault_ipa(vcpu);
56 	fault_ipa |= kvm_vcpu_get_hfar(vcpu) & GENMASK(11, 0);
57 
58 	/* If not for GICV, move on */
59 	if (fault_ipa <  vgic->vgic_cpu_base ||
60 	    fault_ipa >= (vgic->vgic_cpu_base + KVM_VGIC_V2_CPU_SIZE))
61 		return 0;
62 
63 	/* Reject anything but a 32bit access */
64 	if (kvm_vcpu_dabt_get_as(vcpu) != sizeof(u32)) {
65 		__kvm_skip_instr(vcpu);
66 		return -1;
67 	}
68 
69 	/* Not aligned? Don't bother */
70 	if (fault_ipa & 3) {
71 		__kvm_skip_instr(vcpu);
72 		return -1;
73 	}
74 
75 	rd = kvm_vcpu_dabt_get_rd(vcpu);
76 	addr  = hyp_symbol_addr(kvm_vgic_global_state)->vcpu_hyp_va;
77 	addr += fault_ipa - vgic->vgic_cpu_base;
78 
79 	if (kvm_vcpu_dabt_iswrite(vcpu)) {
80 		u32 data = vcpu_get_reg(vcpu, rd);
81 		if (__is_be(vcpu)) {
82 			/* guest pre-swabbed data, undo this for writel() */
83 			data = swab32(data);
84 		}
85 		writel_relaxed(data, addr);
86 	} else {
87 		u32 data = readl_relaxed(addr);
88 		if (__is_be(vcpu)) {
89 			/* guest expects swabbed data */
90 			data = swab32(data);
91 		}
92 		vcpu_set_reg(vcpu, rd, data);
93 	}
94 
95 	__kvm_skip_instr(vcpu);
96 
97 	return 1;
98 }
99