arm64: KVM: Implement 32bit system register save/restore

Implement the 32bit system register save/restore as a direct
translation of the assembly code version.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>

arch/arm64/kvm/hyp/hyp.h

@@ -40,6 +40,8 @@ void __timer_restore_state(struct kvm_vcpu *vcpu);
 
 void __sysreg_save_state(struct kvm_cpu_context *ctxt);
 void __sysreg_restore_state(struct kvm_cpu_context *ctxt);
+void __sysreg32_save_state(struct kvm_vcpu *vcpu);
+void __sysreg32_restore_state(struct kvm_vcpu *vcpu);
 
 #endif /* __ARM64_KVM_HYP_H__ */
 

arch/arm64/kvm/hyp/sysreg-sr.c

@@ -88,3 +88,50 @@ void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
 	write_sysreg(ctxt->gp_regs.elr_el1,	elr_el1);
 	write_sysreg(ctxt->gp_regs.spsr[KVM_SPSR_EL1], spsr_el1);
 }
+
+void __hyp_text __sysreg32_save_state(struct kvm_vcpu *vcpu)
+{
+	u64 *spsr, *sysreg;
+
+	if (read_sysreg(hcr_el2) & HCR_RW)
+		return;
+
+	spsr = vcpu->arch.ctxt.gp_regs.spsr;
+	sysreg = vcpu->arch.ctxt.sys_regs;
+
+	spsr[KVM_SPSR_ABT] = read_sysreg(spsr_abt);
+	spsr[KVM_SPSR_UND] = read_sysreg(spsr_und);
+	spsr[KVM_SPSR_IRQ] = read_sysreg(spsr_irq);
+	spsr[KVM_SPSR_FIQ] = read_sysreg(spsr_fiq);
+
+	sysreg[DACR32_EL2] = read_sysreg(dacr32_el2);
+	sysreg[IFSR32_EL2] = read_sysreg(ifsr32_el2);
+
+	if (!(read_sysreg(cptr_el2) & CPTR_EL2_TFP))
+		sysreg[FPEXC32_EL2] = read_sysreg(fpexc32_el2);
+
+	if (vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY)
+		sysreg[DBGVCR32_EL2] = read_sysreg(dbgvcr32_el2);
+}
+
+void __hyp_text __sysreg32_restore_state(struct kvm_vcpu *vcpu)
+{
+	u64 *spsr, *sysreg;
+
+	if (read_sysreg(hcr_el2) & HCR_RW)
+		return;
+
+	spsr = vcpu->arch.ctxt.gp_regs.spsr;
+	sysreg = vcpu->arch.ctxt.sys_regs;
+
+	write_sysreg(spsr[KVM_SPSR_ABT], spsr_abt);
+	write_sysreg(spsr[KVM_SPSR_UND], spsr_und);
+	write_sysreg(spsr[KVM_SPSR_IRQ], spsr_irq);
+	write_sysreg(spsr[KVM_SPSR_FIQ], spsr_fiq);
+
+	write_sysreg(sysreg[DACR32_EL2], dacr32_el2);
+	write_sysreg(sysreg[IFSR32_EL2], ifsr32_el2);
+
+	if (vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY)
+		write_sysreg(sysreg[DBGVCR32_EL2], dbgvcr32_el2);
+}