[PATCH v4 25/32] KVM: s390: pci: provide routines for enabling/disabling IOAT assist

[Matthew Rosato <mjrosato@xxxxxxxxxxxxx>]

These routines will be wired into a kvm ioctl in orer to respond to
requests to enable / disable a device for PCI I/O Address Translation
assistance via a KVM-managed IOMMU.

Signed-off-by: Matthew Rosato <mjrosato@xxxxxxxxxxxxx>
---
 arch/s390/include/asm/kvm_pci.h |  2 ++
 arch/s390/kvm/pci.c             | 25 +++++++++++++++++++++++++
 arch/s390/kvm/pci.h             |  2 ++
 3 files changed, 29 insertions(+)

diff --git a/arch/s390/include/asm/kvm_pci.h b/arch/s390/include/asm/kvm_pci.h
index ed596880fb06..e27dbede723c 100644
--- a/arch/s390/include/asm/kvm_pci.h
+++ b/arch/s390/include/asm/kvm_pci.h
@@ -30,6 +30,8 @@ struct kvm_zdev {
 int kvm_s390_pci_dev_open(struct zpci_dev *zdev);
 void kvm_s390_pci_dev_release(struct zpci_dev *zdev);
 
+u8 kvm_s390_pci_get_dtsm(struct zpci_dev *zdev);
+
 int zpci_iommu_attach_kvm(struct zpci_dev *zdev, struct kvm *kvm);
 int zpci_iommu_kvm_assign_iota(struct zpci_dev *zdev, u64 iota);
 int zpci_iommu_kvm_remove_iota(struct zpci_dev *zdev);
diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
index 2287c1c6a3e5..1a8b82220b29 100644
--- a/arch/s390/kvm/pci.c
+++ b/arch/s390/kvm/pci.c
@@ -367,6 +367,28 @@ static int kvm_s390_pci_aif_disable(struct zpci_dev *zdev, bool force)
 	return rc;
 }
 
+static int kvm_s390_pci_ioat_enable(struct zpci_dev *zdev, u64 iota)
+{
+	if (IS_ENABLED(CONFIG_S390_KVM_IOMMU))
+		return zpci_iommu_kvm_assign_iota(zdev, iota);
+	else
+		return -EINVAL;
+}
+
+static int kvm_s390_pci_ioat_disable(struct zpci_dev *zdev)
+{
+	if (IS_ENABLED(CONFIG_S390_KVM_IOMMU))
+		return zpci_iommu_kvm_remove_iota(zdev);
+	else
+		return -EINVAL;
+}
+
+u8 kvm_s390_pci_get_dtsm(struct zpci_dev *zdev)
+{
+	return (zdev->dtsm & KVM_S390_PCI_DTSM_MASK);
+}
+EXPORT_SYMBOL_GPL(kvm_s390_pci_get_dtsm);
+
 static int kvm_s390_pci_interp_enable(struct zpci_dev *zdev)
 {
 	u32 gisa;
@@ -432,6 +454,9 @@ static int kvm_s390_pci_interp_disable(struct zpci_dev *zdev, bool force)
 	if (zdev->kzdev->fib.fmt0.aibv != 0)
 		kvm_s390_pci_aif_disable(zdev, force);
 
+	/* If we are using the IOAT assist, disable it now */
+	kvm_s390_pci_ioat_disable(zdev);
+
 	/* Remove the host CLP guest designation */
 	zdev->gisa = 0;
 
diff --git a/arch/s390/kvm/pci.h b/arch/s390/kvm/pci.h
index a95d9fdc91be..867f04cae3a1 100644
--- a/arch/s390/kvm/pci.h
+++ b/arch/s390/kvm/pci.h
@@ -16,6 +16,8 @@
 #include <asm/airq.h>
 #include <asm/kvm_pci.h>
 
+#define KVM_S390_PCI_DTSM_MASK 0x40
+
 struct zpci_gaite {
 	u32 gisa;
 	u8 gisc;
-- 
2.27.0