[RFC PATCH 2/5] 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 | 17 +++++++++++++++++
 virt/kvm/Kconfig         |  2 ++
 virt/kvm/kvm_main.c      | 25 +++++++++++++++++++++++++
 3 files changed, 44 insertions(+)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 7f2e2a09ebbd..25856db74a08 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -836,6 +836,8 @@ bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu);
 void kvm_vcpu_kick(struct kvm_vcpu *vcpu);
 int kvm_vcpu_yield_to(struct kvm_vcpu *target);
 void kvm_vcpu_on_spin(struct kvm_vcpu *vcpu, bool usermode_vcpu_not_eligible);
+int kvm_pinned_vmid_get(struct device *dev);
+int kvm_pinned_vmid_put(struct device *dev);
 
 void kvm_flush_remote_tlbs(struct kvm *kvm);
 void kvm_reload_remote_mmus(struct kvm *kvm);
@@ -1478,4 +1480,19 @@ 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);
+int kvm_arch_pinned_vmid_put(struct kvm *kvm);
+#else
+static inline int kvm_arch_pinned_vmid_get(struct kvm *kvm)
+{
+	return -EINVAL;
+}
+
+static inline int kvm_arch_pinned_vmid_put(struct kvm *kvm)
+{
+	return -EINVAL;
+}
+#endif
+
 #endif
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index 1c37ccd5d402..bb55616c5616 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -63,3 +63,5 @@ config HAVE_KVM_NO_POLL
 
 config KVM_XFER_TO_GUEST_WORK
        bool
+config HAVE_KVM_PINNED_VMID
+       bool
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 2541a17ff1c4..632d391f0e34 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -51,6 +51,7 @@
 #include <linux/io.h>
 #include <linux/lockdep.h>
 #include <linux/kthread.h>
+#include <linux/vfio.h>
 
 #include <asm/processor.h>
 #include <asm/ioctl.h>
@@ -2849,6 +2850,30 @@ bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu)
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_wake_up);
 
+int kvm_pinned_vmid_get(struct device *dev)
+{
+	struct kvm *kvm;
+
+	kvm = vfio_kvm_get_from_dev(dev);
+	if (!kvm)
+		return -EINVAL;
+
+	return kvm_arch_pinned_vmid_get(kvm);
+}
+EXPORT_SYMBOL_GPL(kvm_pinned_vmid_get);
+
+int kvm_pinned_vmid_put(struct device *dev)
+{
+	struct kvm *kvm;
+
+	kvm = vfio_kvm_get_from_dev(dev);
+	if (!kvm)
+		return -EINVAL;
+
+	return kvm_arch_pinned_vmid_put(kvm);
+}
+EXPORT_SYMBOL_GPL(kvm_pinned_vmid_put);
+
 #ifndef CONFIG_S390
 /*
  * Kick a sleeping VCPU, or a guest VCPU in guest mode, into host kernel mode.
-- 
2.17.1