[PATCH 15/21] arm64: KVM: Add panic handling

[Marc Zyngier]

Add the panic handler, together with the small bits of assembly
code to call the kernel's panic implementation.

Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
---
 arch/arm64/kvm/hyp/hyp-entry.S | 11 ++++++++++-
 arch/arm64/kvm/hyp/hyp.h       |  1 +
 arch/arm64/kvm/hyp/switch.c    | 35 +++++++++++++++++++++++++++++++++++
 3 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index e11a129..7218eed 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -141,7 +141,16 @@ el1_irq:
 	mov	x1, #ARM_EXCEPTION_IRQ
 	b	__guest_exit
 
-.macro invalid_vector	label, target = __kvm_hyp_panic
+ENTRY(__hyp_do_panic)
+	mov	lr, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT |\
+		      PSR_MODE_EL1h)
+	msr	spsr_el2, lr
+	ldr	lr, =panic
+	msr	elr_el2, lr
+	eret
+ENDPROC(__hyp_do_panic)
+
+.macro invalid_vector	label, target = __hyp_panic
 	.align	2
 \label:
 	b \target
diff --git a/arch/arm64/kvm/hyp/hyp.h b/arch/arm64/kvm/hyp/hyp.h
index 240fb79..d5d500d 100644
--- a/arch/arm64/kvm/hyp/hyp.h
+++ b/arch/arm64/kvm/hyp/hyp.h
@@ -74,6 +74,7 @@ void __fpsimd_save_state(struct user_fpsimd_state *fp_regs);
 void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs);
 
 u64 __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context *host_ctxt);
+void __noreturn __hyp_do_panic(unsigned long, ...);
 
 #endif /* __ARM64_KVM_HYP_H__ */
 
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index 06d3e20..cdc2a96 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -140,3 +140,38 @@ int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
 
 	return exit_code;
 }
+
+static const char *__hyp_panic_string = "HYP panic:\nPS:%08x PC:%p ESR:%p\nFAR:%p HPFAR:%p PAR:%p\nVCPU:%p\n";
+
+void __hyp_text __noreturn __hyp_panic(void)
+{
+	u64 spsr = read_sysreg(spsr_el2);
+	u64 elr = read_sysreg(elr_el2);
+	u64 par = read_sysreg(par_el1);
+
+	if (read_sysreg(vttbr_el2)) {
+		struct kvm_vcpu *vcpu;
+		struct kvm_cpu_context *host_ctxt;
+
+		vcpu = (struct kvm_vcpu *)read_sysreg(tpidr_el2);
+		host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
+		__deactivate_traps(vcpu);
+		__deactivate_vm(vcpu);
+		__sysreg_restore_state(host_ctxt);
+
+		write_sysreg(host_ctxt->gp_regs.sp_el1, sp_el1);
+	}
+
+	/* Call panic for real */
+	while (1) {
+		unsigned long str_va = (unsigned long)__hyp_panic_string;
+
+		str_va -= HYP_PAGE_OFFSET;
+		str_va += PAGE_OFFSET;
+		__hyp_do_panic(str_va,
+			       spsr,  elr,
+			       read_sysreg(esr_el2),   read_sysreg(far_el2),
+			       read_sysreg(hpfar_el2), par,
+			       read_sysreg(tpidr_el2));
+	}
+}
-- 
2.1.4