[RFC PATCH v2 02/11] KVM: Introduce kvm_vcpu_has_run_once

[Raghavendra Rao Ananta]

Architectures such as arm64 and riscv uses vcpu variables
such as has_run_once and ran_atleast_once, respectively,
to mark if the vCPU has started running. Since these are
architecture agnostic variables, introduce
kvm_vcpu_has_run_once() as a core kvm functionality and
use this instead of the architecture defined variables.

No functional change intended.

Signed-off-by: Raghavendra Rao Ananta <rananta at google.com>
---
 arch/arm64/include/asm/kvm_host.h | 3 ---
 arch/arm64/kvm/arm.c              | 8 ++++----
 arch/arm64/kvm/vgic/vgic-init.c   | 2 +-
 arch/riscv/include/asm/kvm_host.h | 3 ---
 arch/riscv/kvm/vcpu.c             | 7 ++-----
 include/linux/kvm_host.h          | 7 +++++++
 virt/kvm/kvm_main.c               | 1 +
 7 files changed, 15 insertions(+), 16 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 4be8486042a7..02dffe50a20c 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -367,9 +367,6 @@ struct kvm_vcpu_arch {
 	int target;
 	DECLARE_BITMAP(features, KVM_VCPU_MAX_FEATURES);
 
-	/* Detect first run of a vcpu */
-	bool has_run_once;
-
 	/* Virtual SError ESR to restore when HCR_EL2.VSE is set */
 	u64 vsesr_el2;
 
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index f5490afe1ebf..0cc148211b4e 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -344,7 +344,7 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
 
 void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 {
-	if (vcpu->arch.has_run_once && unlikely(!irqchip_in_kernel(vcpu->kvm)))
+	if (kvm_vcpu_has_run_once(vcpu) && unlikely(!irqchip_in_kernel(vcpu->kvm)))
 		static_branch_dec(&userspace_irqchip_in_use);
 
 	kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
@@ -582,13 +582,13 @@ static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu)
 	struct kvm *kvm = vcpu->kvm;
 	int ret = 0;
 
-	if (likely(vcpu->arch.has_run_once))
+	if (likely(kvm_vcpu_has_run_once(vcpu)))
 		return 0;
 
 	if (!kvm_arm_vcpu_is_finalized(vcpu))
 		return -EPERM;
 
-	vcpu->arch.has_run_once = true;
+	vcpu->has_run_once = true;
 
 	kvm_arm_vcpu_init_debug(vcpu);
 
@@ -1116,7 +1116,7 @@ static int kvm_arch_vcpu_ioctl_vcpu_init(struct kvm_vcpu *vcpu,
 	 * need to invalidate the I-cache though, as FWB does *not*
 	 * imply CTR_EL0.DIC.
 	 */
-	if (vcpu->arch.has_run_once) {
+	if (kvm_vcpu_has_run_once(vcpu)) {
 		if (!cpus_have_final_cap(ARM64_HAS_STAGE2_FWB))
 			stage2_unmap_vm(vcpu->kvm);
 		else
diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c
index 0a06d0648970..6fb41097880b 100644
--- a/arch/arm64/kvm/vgic/vgic-init.c
+++ b/arch/arm64/kvm/vgic/vgic-init.c
@@ -91,7 +91,7 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
 		return ret;
 
 	kvm_for_each_vcpu(i, vcpu, kvm) {
-		if (vcpu->arch.has_run_once)
+		if (kvm_vcpu_has_run_once(vcpu))
 			goto out_unlock;
 	}
 	ret = 0;
diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index 25ba21f98504..645e95f61d47 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -147,9 +147,6 @@ struct kvm_vcpu_csr {
 };
 
 struct kvm_vcpu_arch {
-	/* VCPU ran at least once */
-	bool ran_atleast_once;
-
 	/* ISA feature bits (similar to MISA) */
 	unsigned long isa;
 
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index e3d3aed46184..18cbc8b0c03d 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -75,9 +75,6 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 {
 	struct kvm_cpu_context *cntx;
 
-	/* Mark this VCPU never ran */
-	vcpu->arch.ran_atleast_once = false;
-
 	/* Setup ISA features available to VCPU */
 	vcpu->arch.isa = riscv_isa_extension_base(NULL) & KVM_RISCV_ISA_ALLOWED;
 
@@ -190,7 +187,7 @@ static int kvm_riscv_vcpu_set_reg_config(struct kvm_vcpu *vcpu,
 
 	switch (reg_num) {
 	case KVM_REG_RISCV_CONFIG_REG(isa):
-		if (!vcpu->arch.ran_atleast_once) {
+		if (!kvm_vcpu_has_run_once(vcpu)) {
 			vcpu->arch.isa = reg_val;
 			vcpu->arch.isa &= riscv_isa_extension_base(NULL);
 			vcpu->arch.isa &= KVM_RISCV_ISA_ALLOWED;
@@ -682,7 +679,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 	struct kvm_run *run = vcpu->run;
 
 	/* Mark this VCPU ran at least once */
-	vcpu->arch.ran_atleast_once = true;
+	vcpu->has_run_once = true;
 
 	vcpu->arch.srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
 
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 60a35d9fe259..b373929c71eb 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -360,6 +360,8 @@ struct kvm_vcpu {
 	 * it is a valid slot.
 	 */
 	int last_used_slot;
+
+	bool has_run_once;
 };
 
 /* must be called with irqs disabled */
@@ -1847,4 +1849,9 @@ static inline void kvm_handle_signal_exit(struct kvm_vcpu *vcpu)
 /* Max number of entries allowed for each kvm dirty ring */
 #define  KVM_DIRTY_RING_MAX_ENTRIES  65536
 
+static inline bool kvm_vcpu_has_run_once(struct kvm_vcpu *vcpu)
+{
+	return vcpu->has_run_once;
+}
+
 #endif
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 3f6d450355f0..1ec8a8e959b2 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -433,6 +433,7 @@ static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
 	vcpu->ready = false;
 	preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops);
 	vcpu->last_used_slot = 0;
+	vcpu->has_run_once = false;
 }
 
 void kvm_vcpu_destroy(struct kvm_vcpu *vcpu)
-- 
2.34.0.rc1.387.gb447b232ab-goog