[RFC PATCH v2 1/7] KVM: Add generic infrastructure to support pinned VMIDs

[Shameer Kolothum]

Provide generic helper functions to get/put pinned VMIDs if the arch
supports it.

Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi at huawei.com>
---
 include/linux/kvm_host.h | 18 ++++++++++++++++++
 virt/kvm/Kconfig         |  3 +++
 virt/kvm/kvm_main.c      | 23 +++++++++++++++++++++++
 3 files changed, 44 insertions(+)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 7e7fd25b09b3..610e239bea46 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2311,6 +2311,24 @@ static inline void kvm_handle_signal_exit(struct kvm_vcpu *vcpu)
 }
 #endif /* CONFIG_KVM_XFER_TO_GUEST_WORK */
 
+#ifdef CONFIG_HAVE_KVM_PINNED_VMID
+int kvm_arch_pinned_vmid_get(struct kvm *kvm);
+void kvm_arch_pinned_vmid_put(struct kvm *kvm);
+#endif
+
+#ifdef CONFIG_HAVE_KVM_PINNED_VMID
+int kvm_pinned_vmid_get(struct kvm *kvm);
+void kvm_pinned_vmid_put(struct kvm *kvm);
+#else
+static inline int kvm_pinned_vmid_get(struct kvm *kvm)
+{
+	return -EINVAL;
+}
+
+static inline void kvm_pinned_vmid_put(struct kvm *kvm)
+{
+}
+#endif
 /*
  * If more than one page is being (un)accounted, @virt must be the address of
  * the first page of a block of pages what were allocated together (i.e
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index 184dab4ee871..a3052c8e3ac4 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -108,3 +108,6 @@ config KVM_GENERIC_PRIVATE_MEM
        select KVM_GENERIC_MEMORY_ATTRIBUTES
        select KVM_PRIVATE_MEM
        bool
+
+config HAVE_KVM_PINNED_VMID
+       bool
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 10bfc88a69f7..f84d6da5f464 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3918,6 +3918,29 @@ bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu)
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_wake_up);
 
+#ifdef CONFIG_HAVE_KVM_PINNED_VMID
+int kvm_pinned_vmid_get(struct kvm *kvm)
+{
+	int ret;
+
+	if (!kvm_get_kvm_safe(kvm))
+		return -ENOENT;
+	ret  = kvm_arch_pinned_vmid_get(kvm);
+	if (ret < 0)
+		kvm_put_kvm(kvm);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(kvm_pinned_vmid_get);
+
+void kvm_pinned_vmid_put(struct kvm *kvm)
+{
+	kvm_arch_pinned_vmid_put(kvm);
+	kvm_put_kvm(kvm);
+}
+EXPORT_SYMBOL_GPL(kvm_pinned_vmid_put);
+#endif
+
 #ifndef CONFIG_S390
 /*
  * Kick a sleeping VCPU, or a guest VCPU in guest mode, into host kernel mode.
-- 
2.34.1