[PATCH v3 2/4] LoongArch: KVM: Move host CSR_EENTRY save and restore in context switch

[Bibo Mao]

CSR register LOONGARCH_CSR_EENTRY is shared between host cpu and guest
vCPU, KVM need save and restore LOONGARCH_CSR_EENTRY register. Here move
CSR register LOONGARCH_CSR_EENTRY saving in context switch function,
rather than VM enter entry.

At most time VM enter/exit is much more frequent than vCPU thread context
switch.

Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx>
---
 arch/loongarch/kvm/vcpu.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
index 028eb3d5a33b..e82b2c84ce17 100644
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -319,7 +319,6 @@ static int kvm_pre_enter_guest(struct kvm_vcpu *vcpu)
 		 * and it may also clear KVM_REQ_TLB_FLUSH_GPA pending bit
 		 */
 		kvm_late_check_requests(vcpu);
-		vcpu->arch.host_eentry = csr_read64(LOONGARCH_CSR_EENTRY);
 		/* Clear KVM_LARCH_SWCSR_LATEST as CSR will change when enter guest */
 		vcpu->arch.aux_inuse &= ~KVM_LARCH_SWCSR_LATEST;
 
@@ -1624,9 +1623,11 @@ static int _kvm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 	 * If not, any old guest state from this vCPU will have been clobbered.
 	 */
 	context = per_cpu_ptr(vcpu->kvm->arch.vmcs, cpu);
-	if (migrated || (context->last_vcpu != vcpu))
+	if (migrated || (context->last_vcpu != vcpu)) {
 		vcpu->arch.aux_inuse &= ~KVM_LARCH_HWCSR_USABLE;
-	context->last_vcpu = vcpu;
+		context->last_vcpu = vcpu;
+		vcpu->arch.host_eentry = csr_read64(LOONGARCH_CSR_EENTRY);
+	}
 
 	/* Restore timer state regardless */
 	kvm_restore_timer(vcpu);
-- 
2.39.3