[PATCH v6 10/21] KVM: s390: vsie: Refactor kvm_s390_vsie_destroy and extract reusable methods

[Christoph Schlameuss <schlameuss@linux.ibm.com>]

Create a helper method release_gmap_shadow_safe() to simplify releasing
the gmap shadow of a vsie_page and a method kvm_s390_vsie_destroy_page()
reduce nesting.
Both methods will be called from multiple places in upcoming patches.

Signed-off-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
---
 arch/s390/kvm/s390/vsie.c | 42 +++++++++++++++++++++++++++---------------
 1 file changed, 27 insertions(+), 15 deletions(-)

diff --git a/arch/s390/kvm/s390/vsie.c b/arch/s390/kvm/s390/vsie.c
index 75676f493ab2..78d59fc535f7 100644
--- a/arch/s390/kvm/s390/vsie.c
+++ b/arch/s390/kvm/s390/vsie.c
@@ -164,6 +164,17 @@ static void release_gmap_shadow(struct vsie_page *vsie_page)
 	}
 }
 
+static void release_gmap_shadow_safe(struct kvm *kvm, struct vsie_page *vsie_page)
+{
+	if (!vsie_page->gmap_cache.gmap)
+		return;
+
+	guard(spinlock)(&kvm->arch.gmap->children_lock);
+
+	if (vsie_page->gmap_cache.gmap)
+		release_gmap_shadow(vsie_page);
+}
+
 static struct gmap *acquire_gmap_shadow(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 {
 	union ctlreg0 cr0;
@@ -751,13 +762,13 @@ static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 }
 
 /* unpin the scb provided by guest 2, marking it as dirty */
-static void unpin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
+static void unpin_scb(struct kvm *kvm, struct vsie_page *vsie_page,
 		      gpa_t gpa)
 {
 	hpa_t hpa = virt_to_phys(vsie_page->scb_o);
 
 	if (hpa)
-		unpin_guest_page(vcpu->kvm, gpa, hpa);
+		unpin_guest_page(kvm, gpa, hpa);
 	vsie_page->scb_o = NULL;
 }
 
@@ -1585,11 +1596,7 @@ static struct vsie_page *get_vsie_page(struct kvm *kvm, unsigned long addr)
 	mutex_unlock(&kvm->arch.vsie.mutex);
 
 	memset(&vsie_page->scb_s, 0, sizeof(struct kvm_s390_sie_block));
-	if (vsie_page->gmap_cache.gmap) {
-		scoped_guard(spinlock, &kvm->arch.gmap->children_lock)
-			if (vsie_page->gmap_cache.gmap)
-				release_gmap_shadow(vsie_page);
-	}
+	release_gmap_shadow_safe(kvm, vsie_page);
 	prefix_unmapped(vsie_page);
 	vsie_page->fault_addr = 0;
 	vsie_page->scb_s.ihcpu = 0xffffU;
@@ -1644,7 +1651,7 @@ int kvm_s390_handle_vsie(struct kvm_vcpu *vcpu)
 out_unshadow:
 	unshadow_scb(vcpu, vsie_page);
 out_unpin_scb:
-	unpin_scb(vcpu, vsie_page, scb_addr);
+	unpin_scb(vcpu->kvm, vsie_page, scb_addr);
 out_put:
 	put_vsie_page(vsie_page);
 
@@ -1658,24 +1665,29 @@ void kvm_s390_vsie_init(struct kvm *kvm)
 	xa_init_flags(&kvm->arch.vsie.addr_to_page, XA_FLAGS_ACCOUNT);
 }
 
+static void kvm_s390_vsie_destroy_page(struct kvm *kvm, struct vsie_page *vsie_page)
+{
+	unpin_scb(kvm, vsie_page, vsie_page->scb_gpa);
+	release_gmap_shadow_safe(kvm, vsie_page);
+	free_vsie_page(vsie_page);
+}
+
 /* Destroy the vsie data structures. To be called when a vm is destroyed. */
 void kvm_s390_vsie_destroy(struct kvm *kvm)
 {
 	struct vsie_page *vsie_page;
 	int i;
 
-	mutex_lock(&kvm->arch.vsie.mutex);
+	guard(mutex)(&kvm->arch.vsie.mutex);
+
 	for (i = 0; i < kvm->arch.vsie.page_count; i++) {
 		vsie_page = kvm->arch.vsie.pages[i];
-		scoped_guard(spinlock, &kvm->arch.gmap->children_lock)
-			if (vsie_page->gmap_cache.gmap)
-				release_gmap_shadow(vsie_page);
 		kvm->arch.vsie.pages[i] = NULL;
-		free_vsie_page(vsie_page);
+		kvm_s390_vsie_destroy_page(kvm, vsie_page);
 	}
-	xa_destroy(&kvm->arch.vsie.addr_to_page);
+
 	kvm->arch.vsie.page_count = 0;
-	mutex_unlock(&kvm->arch.vsie.mutex);
+	xa_destroy(&kvm->arch.vsie.addr_to_page);
 }
 
 void kvm_s390_vsie_kick(struct kvm_vcpu *vcpu)

-- 
2.55.0