KVM: Take kvm instead of vcpu to mmu_notifier_retry

The mmu_notifier_retry is not specific to any vcpu (and never will be)
so only take struct kvm as a parameter.

The motivation is the ARM mmu code that needs to call this from
somewhere where we long let go of the vcpu pointer.
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/powerpc/kvm/book3s_64_mmu_hv.c

@@ -710,7 +710,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
 
 	/* Check if we might have been invalidated; let the guest retry if so */
 	ret = RESUME_GUEST;
-	if (mmu_notifier_retry(vcpu, mmu_seq)) {
+	if (mmu_notifier_retry(vcpu->kvm, mmu_seq)) {
 		unlock_rmap(rmap);
 		goto out_unlock;
 	}

arch/powerpc/kvm/book3s_hv_rm_mmu.c

@@ -297,7 +297,7 @@ long kvmppc_h_enter(struct kvm_vcpu *vcpu, unsigned long flags,
 		lock_rmap(rmap);
 		/* Check for pending invalidations under the rmap chain lock */
 		if (kvm->arch.using_mmu_notifiers &&
-		    mmu_notifier_retry(vcpu, mmu_seq)) {
+		    mmu_notifier_retry(vcpu->kvm, mmu_seq)) {
 			/* inval in progress, write a non-present HPTE */
 			pteh |= HPTE_V_ABSENT;
 			pteh &= ~HPTE_V_VALID;

arch/x86/kvm/mmu.c

@@ -2886,7 +2886,7 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,
 		return r;
 
 	spin_lock(&vcpu->kvm->mmu_lock);
-	if (mmu_notifier_retry(vcpu, mmu_seq))
+	if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
 		goto out_unlock;
 	kvm_mmu_free_some_pages(vcpu);
 	if (likely(!force_pt_level))
@@ -3355,7 +3355,7 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
 		return r;
 
 	spin_lock(&vcpu->kvm->mmu_lock);
-	if (mmu_notifier_retry(vcpu, mmu_seq))
+	if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
 		goto out_unlock;
 	kvm_mmu_free_some_pages(vcpu);
 	if (likely(!force_pt_level))

arch/x86/kvm/paging_tmpl.h

@@ -565,7 +565,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
 		return r;
 
 	spin_lock(&vcpu->kvm->mmu_lock);
-	if (mmu_notifier_retry(vcpu, mmu_seq))
+	if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
 		goto out_unlock;
 
 	kvm_mmu_audit(vcpu, AUDIT_PRE_PAGE_FAULT);

include/linux/kvm_host.h

@@ -841,9 +841,9 @@ extern struct kvm_stats_debugfs_item debugfs_entries[];
 extern struct dentry *kvm_debugfs_dir;
 
 #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
-static inline int mmu_notifier_retry(struct kvm_vcpu *vcpu, unsigned long mmu_seq)
+static inline int mmu_notifier_retry(struct kvm *kvm, unsigned long mmu_seq)
 {
-	if (unlikely(vcpu->kvm->mmu_notifier_count))
+	if (unlikely(kvm->mmu_notifier_count))
 		return 1;
 	/*
 	 * Ensure the read of mmu_notifier_count happens before the read
@@ -856,7 +856,7 @@ static inline int mmu_notifier_retry(struct kvm_vcpu *vcpu, unsigned long mmu_se
 	 * can't rely on kvm->mmu_lock to keep things ordered.
 	 */
 	smp_rmb();
-	if (vcpu->kvm->mmu_notifier_seq != mmu_seq)
+	if (kvm->mmu_notifier_seq != mmu_seq)
 		return 1;
 	return 0;
 }