arm64: KVM: VHE: Differenciate host/guest sysreg save/restore

With ARMv8, host and guest share the same system register file,
making the save/restore procedure completely symetrical.
With VHE, host and guest now have different requirements, as they
use different sysregs.

In order to prepare for this, add split sysreg save/restore functions
for both host and guest. No functional changes yet.

Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

arch/arm64/kvm/hyp/hyp.h

@@ -153,8 +153,10 @@ void __vgic_v3_restore_state(struct kvm_vcpu *vcpu);
 void __timer_save_state(struct kvm_vcpu *vcpu);
 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 __sysreg_save_host_state(struct kvm_cpu_context *ctxt);
+void __sysreg_restore_host_state(struct kvm_cpu_context *ctxt);
+void __sysreg_save_guest_state(struct kvm_cpu_context *ctxt);
+void __sysreg_restore_guest_state(struct kvm_cpu_context *ctxt);
 void __sysreg32_save_state(struct kvm_vcpu *vcpu);
 void __sysreg32_restore_state(struct kvm_vcpu *vcpu);
 

arch/arm64/kvm/hyp/switch.c

@@ -102,7 +102,7 @@ static int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
 	host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
 	guest_ctxt = &vcpu->arch.ctxt;
 
-	__sysreg_save_state(host_ctxt);
+	__sysreg_save_host_state(host_ctxt);
 	__debug_cond_save_host_state(vcpu);
 
 	__activate_traps(vcpu);
@@ -116,7 +116,7 @@ static int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
 	 * to Cortex-A57 erratum #852523.
 	 */
 	__sysreg32_restore_state(vcpu);
-	__sysreg_restore_state(guest_ctxt);
+	__sysreg_restore_guest_state(guest_ctxt);
 	__debug_restore_state(vcpu, kern_hyp_va(vcpu->arch.debug_ptr), guest_ctxt);
 
 	/* Jump in the fire! */
@@ -125,7 +125,7 @@ static int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
 
 	fp_enabled = __fpsimd_enabled();
 
-	__sysreg_save_state(guest_ctxt);
+	__sysreg_save_guest_state(guest_ctxt);
 	__sysreg32_save_state(vcpu);
 	__timer_save_state(vcpu);
 	__vgic_save_state(vcpu);
@@ -133,7 +133,7 @@ static int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
 	__deactivate_traps(vcpu);
 	__deactivate_vm(vcpu);
 
-	__sysreg_restore_state(host_ctxt);
+	__sysreg_restore_host_state(host_ctxt);
 
 	if (fp_enabled) {
 		__fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs);
@@ -165,7 +165,7 @@ void __hyp_text __noreturn __hyp_panic(void)
 		host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
 		__deactivate_traps(vcpu);
 		__deactivate_vm(vcpu);
-		__sysreg_restore_state(host_ctxt);
+		__sysreg_restore_host_state(host_ctxt);
 	}
 
 	/* Call panic for real */

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

@@ -24,7 +24,7 @@
 #include "hyp.h"
 
 /* ctxt is already in the HYP VA space */
-void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
+static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
 {
 	ctxt->sys_regs[MPIDR_EL1]	= read_sysreg(vmpidr_el2);
 	ctxt->sys_regs[CSSELR_EL1]	= read_sysreg(csselr_el1);
@@ -57,7 +57,17 @@ void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
 	ctxt->gp_regs.spsr[KVM_SPSR_EL1]= read_sysreg(spsr_el1);
 }
 
-void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
+void __hyp_text __sysreg_save_host_state(struct kvm_cpu_context *ctxt)
+{
+	__sysreg_save_state(ctxt);
+}
+
+void __hyp_text __sysreg_save_guest_state(struct kvm_cpu_context *ctxt)
+{
+	__sysreg_save_state(ctxt);
+}
+
+static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
 {
 	write_sysreg(ctxt->sys_regs[MPIDR_EL1],	  vmpidr_el2);
 	write_sysreg(ctxt->sys_regs[CSSELR_EL1],  csselr_el1);
@@ -90,6 +100,16 @@ void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
 	write_sysreg(ctxt->gp_regs.spsr[KVM_SPSR_EL1], spsr_el1);
 }
 
+void __hyp_text __sysreg_restore_host_state(struct kvm_cpu_context *ctxt)
+{
+	__sysreg_restore_state(ctxt);
+}
+
+void __hyp_text __sysreg_restore_guest_state(struct kvm_cpu_context *ctxt)
+{
+	__sysreg_restore_state(ctxt);
+}
+
 void __hyp_text __sysreg32_save_state(struct kvm_vcpu *vcpu)
 {
 	u64 *spsr, *sysreg;