arm64: KVM: Implement vgic-v3 save/restore

Implement the vgic-v3 save restore as a direct translation of
the assembly code version.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

arch/arm64/kvm/hyp/Makefile

@@ -3,3 +3,4 @@
 #
 
 obj-$(CONFIG_KVM_ARM_HOST) += vgic-v2-sr.o
+obj-$(CONFIG_KVM_ARM_HOST) += vgic-v3-sr.o

arch/arm64/kvm/hyp/hyp.h

@@ -32,5 +32,8 @@
 void __vgic_v2_save_state(struct kvm_vcpu *vcpu);
 void __vgic_v2_restore_state(struct kvm_vcpu *vcpu);
 
+void __vgic_v3_save_state(struct kvm_vcpu *vcpu);
+void __vgic_v3_restore_state(struct kvm_vcpu *vcpu);
+
 #endif /* __ARM64_KVM_HYP_H__ */
 

arch/arm64/kvm/hyp/vgic-v3-sr.c

+/*
+ * Copyright (C) 2012-2015 - ARM Ltd
+ * Author: Marc Zyngier <marc.zyngier@arm.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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/compiler.h>
+#include <linux/irqchip/arm-gic-v3.h>
+#include <linux/kvm_host.h>
+
+#include <asm/kvm_mmu.h>
+
+#include "hyp.h"
+
+#define vtr_to_max_lr_idx(v)		((v) & 0xf)
+#define vtr_to_nr_pri_bits(v)		(((u32)(v) >> 29) + 1)
+
+#define read_gicreg(r)							\
+	({								\
+		u64 reg;						\
+		asm volatile("mrs_s %0, " __stringify(r) : "=r" (reg));	\
+		reg;							\
+	})
+
+#define write_gicreg(v,r)						\
+	do {								\
+		u64 __val = (v);					\
+		asm volatile("msr_s " __stringify(r) ", %0" : : "r" (__val));\
+	} while (0)
+
+/* vcpu is already in the HYP VA space */
+void __hyp_text __vgic_v3_save_state(struct kvm_vcpu *vcpu)
+{
+	struct vgic_v3_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v3;
+	u64 val;
+	u32 max_lr_idx, nr_pri_bits;
+
+	/*
+	 * Make sure stores to the GIC via the memory mapped interface
+	 * are now visible to the system register interface.
+	 */
+	dsb(st);
+
+	cpu_if->vgic_vmcr  = read_gicreg(ICH_VMCR_EL2);
+	cpu_if->vgic_misr  = read_gicreg(ICH_MISR_EL2);
+	cpu_if->vgic_eisr  = read_gicreg(ICH_EISR_EL2);
+	cpu_if->vgic_elrsr = read_gicreg(ICH_ELSR_EL2);
+
+	write_gicreg(0, ICH_HCR_EL2);
+	val = read_gicreg(ICH_VTR_EL2);
+	max_lr_idx = vtr_to_max_lr_idx(val);
+	nr_pri_bits = vtr_to_nr_pri_bits(val);
+
+	switch (max_lr_idx) {
+	case 15:
+		cpu_if->vgic_lr[VGIC_V3_LR_INDEX(15)] = read_gicreg(ICH_LR15_EL2);
+	case 14:
+		cpu_if->vgic_lr[VGIC_V3_LR_INDEX(14)] = read_gicreg(ICH_LR14_EL2);
+	case 13:
+		cpu_if->vgic_lr[VGIC_V3_LR_INDEX(13)] = read_gicreg(ICH_LR13_EL2);
+	case 12:
+		cpu_if->vgic_lr[VGIC_V3_LR_INDEX(12)] = read_gicreg(ICH_LR12_EL2);
+	case 11:
+		cpu_if->vgic_lr[VGIC_V3_LR_INDEX(11)] = read_gicreg(ICH_LR11_EL2);
+	case 10:
+		cpu_if->vgic_lr[VGIC_V3_LR_INDEX(10)] = read_gicreg(ICH_LR10_EL2);
+	case 9:
+		cpu_if->vgic_lr[VGIC_V3_LR_INDEX(9)] = read_gicreg(ICH_LR9_EL2);
+	case 8:
+		cpu_if->vgic_lr[VGIC_V3_LR_INDEX(8)] = read_gicreg(ICH_LR8_EL2);
+	case 7:
+		cpu_if->vgic_lr[VGIC_V3_LR_INDEX(7)] = read_gicreg(ICH_LR7_EL2);
+	case 6:
+		cpu_if->vgic_lr[VGIC_V3_LR_INDEX(6)] = read_gicreg(ICH_LR6_EL2);
+	case 5:
+		cpu_if->vgic_lr[VGIC_V3_LR_INDEX(5)] = read_gicreg(ICH_LR5_EL2);
+	case 4:
+		cpu_if->vgic_lr[VGIC_V3_LR_INDEX(4)] = read_gicreg(ICH_LR4_EL2);
+	case 3:
+		cpu_if->vgic_lr[VGIC_V3_LR_INDEX(3)] = read_gicreg(ICH_LR3_EL2);
+	case 2:
+		cpu_if->vgic_lr[VGIC_V3_LR_INDEX(2)] = read_gicreg(ICH_LR2_EL2);
+	case 1:
+		cpu_if->vgic_lr[VGIC_V3_LR_INDEX(1)] = read_gicreg(ICH_LR1_EL2);
+	case 0:
+		cpu_if->vgic_lr[VGIC_V3_LR_INDEX(0)] = read_gicreg(ICH_LR0_EL2);
+	}
+
+	switch (nr_pri_bits) {
+	case 7:
+		cpu_if->vgic_ap0r[3] = read_gicreg(ICH_AP0R3_EL2);
+		cpu_if->vgic_ap0r[2] = read_gicreg(ICH_AP0R2_EL2);
+	case 6:
+		cpu_if->vgic_ap0r[1] = read_gicreg(ICH_AP0R1_EL2);
+	default:
+		cpu_if->vgic_ap0r[0] = read_gicreg(ICH_AP0R0_EL2);
+	}
+
+	switch (nr_pri_bits) {
+	case 7:
+		cpu_if->vgic_ap1r[3] = read_gicreg(ICH_AP1R3_EL2);
+		cpu_if->vgic_ap1r[2] = read_gicreg(ICH_AP1R2_EL2);
+	case 6:
+		cpu_if->vgic_ap1r[1] = read_gicreg(ICH_AP1R1_EL2);
+	default:
+		cpu_if->vgic_ap1r[0] = read_gicreg(ICH_AP1R0_EL2);
+	}
+
+	val = read_gicreg(ICC_SRE_EL2);
+	write_gicreg(val | ICC_SRE_EL2_ENABLE, ICC_SRE_EL2);
+	isb(); /* Make sure ENABLE is set at EL2 before setting SRE at EL1 */
+	write_gicreg(1, ICC_SRE_EL1);
+}
+
+void __hyp_text __vgic_v3_restore_state(struct kvm_vcpu *vcpu)
+{
+	struct vgic_v3_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v3;
+	u64 val;
+	u32 max_lr_idx, nr_pri_bits;
+
+	/*
+	 * VFIQEn is RES1 if ICC_SRE_EL1.SRE is 1. This causes a
+	 * Group0 interrupt (as generated in GICv2 mode) to be
+	 * delivered as a FIQ to the guest, with potentially fatal
+	 * consequences. So we must make sure that ICC_SRE_EL1 has
+	 * been actually programmed with the value we want before
+	 * starting to mess with the rest of the GIC.
+	 */
+	write_gicreg(cpu_if->vgic_sre, ICC_SRE_EL1);
+	isb();
+
+	write_gicreg(cpu_if->vgic_hcr, ICH_HCR_EL2);
+	write_gicreg(cpu_if->vgic_vmcr, ICH_VMCR_EL2);
+
+	val = read_gicreg(ICH_VTR_EL2);
+	max_lr_idx = vtr_to_max_lr_idx(val);
+	nr_pri_bits = vtr_to_nr_pri_bits(val);
+
+	switch (nr_pri_bits) {
+	case 7:
+		 write_gicreg(cpu_if->vgic_ap1r[3], ICH_AP1R3_EL2);
+		 write_gicreg(cpu_if->vgic_ap1r[2], ICH_AP1R2_EL2);
+	case 6:
+		 write_gicreg(cpu_if->vgic_ap1r[1], ICH_AP1R1_EL2);
+	default:
+		 write_gicreg(cpu_if->vgic_ap1r[0], ICH_AP1R0_EL2);
+	}	 	                           
+		 	                           
+	switch (nr_pri_bits) {
+	case 7:
+		 write_gicreg(cpu_if->vgic_ap0r[3], ICH_AP0R3_EL2);
+		 write_gicreg(cpu_if->vgic_ap0r[2], ICH_AP0R2_EL2);
+	case 6:
+		 write_gicreg(cpu_if->vgic_ap0r[1], ICH_AP0R1_EL2);
+	default:
+		 write_gicreg(cpu_if->vgic_ap0r[0], ICH_AP0R0_EL2);
+	}
+
+	switch (max_lr_idx) {
+	case 15:
+		write_gicreg(cpu_if->vgic_lr[VGIC_V3_LR_INDEX(15)], ICH_LR15_EL2);
+	case 14:
+		write_gicreg(cpu_if->vgic_lr[VGIC_V3_LR_INDEX(14)], ICH_LR14_EL2);
+	case 13:
+		write_gicreg(cpu_if->vgic_lr[VGIC_V3_LR_INDEX(13)], ICH_LR13_EL2);
+	case 12:
+		write_gicreg(cpu_if->vgic_lr[VGIC_V3_LR_INDEX(12)], ICH_LR12_EL2);
+	case 11:
+		write_gicreg(cpu_if->vgic_lr[VGIC_V3_LR_INDEX(11)], ICH_LR11_EL2);
+	case 10:
+		write_gicreg(cpu_if->vgic_lr[VGIC_V3_LR_INDEX(10)], ICH_LR10_EL2);
+	case 9:
+		write_gicreg(cpu_if->vgic_lr[VGIC_V3_LR_INDEX(9)], ICH_LR9_EL2);
+	case 8:
+		write_gicreg(cpu_if->vgic_lr[VGIC_V3_LR_INDEX(8)], ICH_LR8_EL2);
+	case 7:
+		write_gicreg(cpu_if->vgic_lr[VGIC_V3_LR_INDEX(7)], ICH_LR7_EL2);
+	case 6:
+		write_gicreg(cpu_if->vgic_lr[VGIC_V3_LR_INDEX(6)], ICH_LR6_EL2);
+	case 5:
+		write_gicreg(cpu_if->vgic_lr[VGIC_V3_LR_INDEX(5)], ICH_LR5_EL2);
+	case 4:
+		write_gicreg(cpu_if->vgic_lr[VGIC_V3_LR_INDEX(4)], ICH_LR4_EL2);
+	case 3:
+		write_gicreg(cpu_if->vgic_lr[VGIC_V3_LR_INDEX(3)], ICH_LR3_EL2);
+	case 2:
+		write_gicreg(cpu_if->vgic_lr[VGIC_V3_LR_INDEX(2)], ICH_LR2_EL2);
+	case 1:
+		write_gicreg(cpu_if->vgic_lr[VGIC_V3_LR_INDEX(1)], ICH_LR1_EL2);
+	case 0:
+		write_gicreg(cpu_if->vgic_lr[VGIC_V3_LR_INDEX(0)], ICH_LR0_EL2);
+	}
+
+	/*
+	 * Ensures that the above will have reached the
+	 * (re)distributors. This ensure the guest will read the
+	 * correct values from the memory-mapped interface.
+	 */
+	isb();
+	dsb(sy);
+
+	/*
+	 * Prevent the guest from touching the GIC system registers if
+	 * SRE isn't enabled for GICv3 emulation.
+	 */
+	if (!cpu_if->vgic_sre) {
+		write_gicreg(read_gicreg(ICC_SRE_EL2) & ~ICC_SRE_EL2_ENABLE,
+			     ICC_SRE_EL2);
+	}
+}
+
+u64 __hyp_text __vgic_v3_read_ich_vtr_el2(void)
+{
+	return read_gicreg(ICH_VTR_EL2);
+}