[PATCH 04/23] KVM: PPC: Book3S HV: Handle making H_ENTER_NESTED hcall in a separate function

[Suraj Jitindar Singh <sjitindarsingh@gmail.com>]

A pseries guest (that is a guest acting as a guest hypervisor) which
would like to run it's own guest (a nested guest) must perform this by
invoking the top level hypervisor via the H_ENTER_NESTED hcall.

Separate out the code which handles calling this into a separate
function for code clarity and readability.

No functional change.

Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
---
 arch/powerpc/kvm/book3s_hv.c | 88 ++++++++++++++++++++++++--------------------
 1 file changed, 49 insertions(+), 39 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index ce960301bfaa..4901738a3c31 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -3367,7 +3367,55 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc)
 }
 
 /*
+ * Handle making the H_ENTER_NESTED hcall if we're pseries.
+ */
+static int kvmhv_pseries_enter_guest(struct kvm_vcpu *vcpu, u64 time_limit,
+				     unsigned long lpcr)
+{
+	/* call our hypervisor to load up HV regs and go */
+	struct hv_guest_state hvregs;
+	/* we need to save/restore host & guest psscr since L0 doesn't for us */
+	unsigned long host_psscr;
+	int trap;
+
+	host_psscr = mfspr(SPRN_PSSCR_PR);
+	mtspr(SPRN_PSSCR_PR, vcpu->arch.psscr);
+	kvmhv_save_hv_regs(vcpu, &hvregs);
+	hvregs.lpcr = lpcr;
+	vcpu->arch.regs.msr = vcpu->arch.shregs.msr;
+	hvregs.version = HV_GUEST_STATE_VERSION;
+	if (vcpu->arch.nested) {
+		hvregs.lpid = vcpu->arch.nested->shadow_lpid;
+		hvregs.vcpu_token = vcpu->arch.nested_vcpu_id;
+	} else {
+		hvregs.lpid = vcpu->kvm->arch.lpid;
+		hvregs.vcpu_token = vcpu->vcpu_id;
+	}
+	hvregs.hdec_expiry = time_limit;
+	trap = plpar_hcall_norets(H_ENTER_NESTED, __pa(&hvregs),
+				  __pa(&vcpu->arch.regs));
+	kvmhv_restore_hv_return_state(vcpu, &hvregs);
+	vcpu->arch.shregs.msr = vcpu->arch.regs.msr;
+	vcpu->arch.shregs.dar = mfspr(SPRN_DAR);
+	vcpu->arch.shregs.dsisr = mfspr(SPRN_DSISR);
+	vcpu->arch.psscr = mfspr(SPRN_PSSCR_PR);
+	mtspr(SPRN_PSSCR_PR, host_psscr);
+
+	/* H_CEDE has to be handled now, not later */
+	if (trap == BOOK3S_INTERRUPT_SYSCALL && !vcpu->arch.nested &&
+	    kvmppc_get_gpr(vcpu, 3) == H_CEDE) {
+		kvmppc_nested_cede(vcpu);
+		trap = 0;
+	}
+
+	return trap;
+}
+
+/*
  * Load up hypervisor-mode registers on P9.
+ * This is only called on baremetal (powernv) systems i.e. where
+ * CPU_FTR_HVMODE is set. This is only used for radix guests, however that
+ * radix guest may be a direct guest of this hypervisor or a nested guest.
  */
 static int kvmhv_load_hv_regs_and_go(struct kvm_vcpu *vcpu, u64 time_limit,
 				     unsigned long lpcr)
@@ -3569,45 +3617,7 @@ int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu, u64 time_limit,
 	mtspr(SPRN_DEC, vcpu->arch.dec_expires - mftb());
 
 	if (kvmhv_on_pseries()) {
-		/*
-		 * We need to save and restore the guest visible part of the
-		 * psscr (i.e. using SPRN_PSSCR_PR) since the hypervisor
-		 * doesn't do this for us. Note only required if pseries since
-		 * this is done in kvmhv_load_hv_regs_and_go() below otherwise.
-		 */
-		unsigned long host_psscr;
-		/* call our hypervisor to load up HV regs and go */
-		struct hv_guest_state hvregs;
-
-		host_psscr = mfspr(SPRN_PSSCR_PR);
-		mtspr(SPRN_PSSCR_PR, vcpu->arch.psscr);
-		kvmhv_save_hv_regs(vcpu, &hvregs);
-		hvregs.lpcr = lpcr;
-		vcpu->arch.regs.msr = vcpu->arch.shregs.msr;
-		hvregs.version = HV_GUEST_STATE_VERSION;
-		if (vcpu->arch.nested) {
-			hvregs.lpid = vcpu->arch.nested->shadow_lpid;
-			hvregs.vcpu_token = vcpu->arch.nested_vcpu_id;
-		} else {
-			hvregs.lpid = vcpu->kvm->arch.lpid;
-			hvregs.vcpu_token = vcpu->vcpu_id;
-		}
-		hvregs.hdec_expiry = time_limit;
-		trap = plpar_hcall_norets(H_ENTER_NESTED, __pa(&hvregs),
-					  __pa(&vcpu->arch.regs));
-		kvmhv_restore_hv_return_state(vcpu, &hvregs);
-		vcpu->arch.shregs.msr = vcpu->arch.regs.msr;
-		vcpu->arch.shregs.dar = mfspr(SPRN_DAR);
-		vcpu->arch.shregs.dsisr = mfspr(SPRN_DSISR);
-		vcpu->arch.psscr = mfspr(SPRN_PSSCR_PR);
-		mtspr(SPRN_PSSCR_PR, host_psscr);
-
-		/* H_CEDE has to be handled now, not later */
-		if (trap == BOOK3S_INTERRUPT_SYSCALL && !vcpu->arch.nested &&
-		    kvmppc_get_gpr(vcpu, 3) == H_CEDE) {
-			kvmppc_nested_cede(vcpu);
-			trap = 0;
-		}
+		trap = kvmhv_pseries_enter_guest(vcpu, time_limit, lpcr);
 	} else {
 		trap = kvmhv_load_hv_regs_and_go(vcpu, time_limit, lpcr);
 	}
-- 
2.13.6