[PATCH 32/60] kvm: Allocate struct kvm_run only for struct kvm_vcpu_common

[Jörg Rödel]

From: Paolo Bonzini <pbonzini@xxxxxxxxxx>

Share the struct kvm_run across all planes for one VCPU id.

Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Co-developed-by: Joerg Roedel <joerg.roedel@xxxxxxx>
Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
---
 include/linux/kvm_host.h |  3 +++
 virt/kvm/kvm_main.c      | 29 ++++++++++++++++-------------
 2 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 55e3e9046975..385e1ee8fd3a 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -327,6 +327,9 @@ struct kvm_mmio_fragment {
 struct kvm_vcpu_common {
 	struct kvm *kvm;
 
+	/* kvm_run struct shared across all planes */
+	struct kvm_run *run;
+
 	int vcpu_idx; /* index into kvm->planes[]->vcpu_array */
 
 	/* Currently active VCPU */
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 4f2c8f46a0d3..2d0d5f4fd356 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -441,6 +441,7 @@ void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
 static int kvm_vcpu_init_common(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned long id)
 {
 	struct kvm_vcpu_common *common __free(kfree) = kzalloc(sizeof(*common), GFP_KERNEL_ACCOUNT);
+	struct page *page;
 	int r;
 
 	/*
@@ -466,6 +467,14 @@ static int kvm_vcpu_init_common(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned
 
 	common->vcpu_idx = atomic_read(&kvm->online_vcpus);
 
+	BUILD_BUG_ON(sizeof(struct kvm_run) > PAGE_SIZE);
+	page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
+	if (!page) {
+		r = -ENOMEM;
+		goto out_drop_counter;
+	}
+	common->run = page_address(page);
+
 	mutex_init(&common->mutex);
 
 #ifndef __KVM_HAVE_ARCH_WQP
@@ -487,7 +496,7 @@ static int kvm_vcpu_init_common(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned
 		r = kvm_dirty_ring_alloc(kvm, &common->dirty_ring,
 					 id, kvm->dirty_ring_size);
 		if (r)
-			goto out_drop_counter;
+			goto out_free_run;
 	}
 
 	r = kvm_arch_vcpu_common_init(common);
@@ -503,6 +512,8 @@ static int kvm_vcpu_init_common(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned
 
 out_free_dirty_ring:
 	kvm_dirty_ring_free(&common->dirty_ring);
+out_free_run:
+	free_page((unsigned long)common->run);
 out_drop_counter:
 	mutex_lock(&kvm->lock);
 	kvm->created_vcpus--;
@@ -546,6 +557,7 @@ static void kvm_vcpu_common_destroy(struct kvm_vcpu *vcpu)
 	struct kvm *kvm = common->kvm;
 
 	vcpu->common = NULL;
+	vcpu->run = NULL;
 
 	if (vcpu->plane_level != 0)
 	       return;
@@ -563,6 +575,7 @@ static void kvm_vcpu_common_destroy(struct kvm_vcpu *vcpu)
 	 */
 	put_pid(common->pid);
 	kvm_dirty_ring_free(&common->dirty_ring);
+	free_page((unsigned long)common->run);
 	kfree(common);
 }
 
@@ -4337,7 +4350,6 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, unsigned long id)
 {
 	int r = -EINVAL;
 	struct kvm_vcpu *vcpu;
-	struct page *page;
 
 	mutex_lock(&kvm->lock);
 	if (kvm->created_vcpus >= kvm->max_vcpus) {
@@ -4359,20 +4371,13 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, unsigned long id)
 		goto vcpu_free;
 
 	vcpu->vcpu_idx = vcpu->common->vcpu_idx;
-
-	BUILD_BUG_ON(sizeof(struct kvm_run) > PAGE_SIZE);
-	page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
-	if (!page) {
-		r = -ENOMEM;
-		goto vcpu_free_common;
-	}
-	vcpu->run = page_address(page);
+	vcpu->run = vcpu->common->run;
 
 	kvm_vcpu_init(vcpu, kvm, id);
 
 	r = kvm_arch_vcpu_create(vcpu);
 	if (r)
-		goto vcpu_free_run_page;
+		goto vcpu_free_common;
 
 	mutex_lock(&kvm->lock);
 
@@ -4415,8 +4420,6 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, unsigned long id)
 unlock_vcpu_destroy:
 	mutex_unlock(&kvm->lock);
 	kvm_arch_vcpu_destroy(vcpu);
-vcpu_free_run_page:
-	free_page((unsigned long)vcpu->run);
 vcpu_free_common:
 	kvm_vcpu_common_destroy(vcpu);
 vcpu_free:
-- 
2.53.0