[PATCH v4 26/32] KVM: s390: pci: handle refresh of PCI translations

[Matthew Rosato <mjrosato@xxxxxxxxxxxxx>]

Add a routine that will perform a shadow operation between a guest
and host IOAT.  A subsequent patch will invoke this in response to
an 04 RPCIT instruction intercept.

Signed-off-by: Matthew Rosato <mjrosato@xxxxxxxxxxxxx>
---
 arch/s390/include/asm/kvm_pci.h |  1 +
 arch/s390/kvm/pci.c             | 31 ++++++++++++++++++++++++++++++-
 arch/s390/kvm/pci.h             |  3 +++
 3 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/arch/s390/include/asm/kvm_pci.h b/arch/s390/include/asm/kvm_pci.h
index e27dbede723c..9578b5dafb45 100644
--- a/arch/s390/include/asm/kvm_pci.h
+++ b/arch/s390/include/asm/kvm_pci.h
@@ -25,6 +25,7 @@ struct kvm_zdev {
 	struct zpci_fib fib;
 	struct notifier_block nb;
 	struct list_head entry;
+	u64 rpcit_count;
 };
 
 int kvm_s390_pci_dev_open(struct zpci_dev *zdev);
diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
index 1a8b82220b29..40d2fadbfbd5 100644
--- a/arch/s390/kvm/pci.c
+++ b/arch/s390/kvm/pci.c
@@ -8,6 +8,7 @@
  */
 
 #include <linux/kvm_host.h>
+#include <linux/iommu.h>
 #include <linux/pci.h>
 #include <linux/vfio.h>
 #include <asm/kvm_pci.h>
@@ -173,6 +174,30 @@ int kvm_s390_pci_aen_init(u8 nisc)
 	return rc;
 }
 
+int kvm_s390_pci_refresh_trans(struct kvm_vcpu *vcpu, unsigned long req,
+			       unsigned long start, unsigned long size)
+{
+	struct kvm_zdev *kzdev;
+	u32 fh = req >> 32;
+	int rc;
+
+	/* Make sure this is a valid device associated with this guest */
+	kzdev = get_kzdev_by_fh(vcpu->kvm, fh);
+	if (!kzdev)
+		return -EINVAL;
+
+	/*
+	 * The KVM-managed IOMMU map operation will synchronize the associated
+	 * guest IOAT tables with the host DMA tables.  A physical address is
+	 * not specified as it will be derived from pinned guest PTEs
+	 */
+	rc = iommu_map(kzdev->dom, start, 0, size, IOMMU_WRITE | IOMMU_READ);
+
+	kzdev->rpcit_count++;
+
+	return rc;
+}
+
 /* Modify PCI: Register floating adapter interruption forwarding */
 static int kvm_zpci_set_airq(struct zpci_dev *zdev)
 {
@@ -716,6 +741,8 @@ void kvm_s390_pci_clear_list(struct kvm *kvm)
 
 int kvm_s390_pci_init(void)
 {
+	int rc;
+
 	aift = kzalloc(sizeof(struct zpci_aift), GFP_KERNEL);
 	if (!aift)
 		return -ENOMEM;
@@ -723,5 +750,7 @@ int kvm_s390_pci_init(void)
 	spin_lock_init(&aift->gait_lock);
 	mutex_init(&aift->aift_lock);
 
-	return 0;
+	rc = zpci_get_mdd(&aift->mdd);
+
+	return rc;
 }
diff --git a/arch/s390/kvm/pci.h b/arch/s390/kvm/pci.h
index 867f04cae3a1..2cb1b27396c1 100644
--- a/arch/s390/kvm/pci.h
+++ b/arch/s390/kvm/pci.h
@@ -33,6 +33,7 @@ struct zpci_aift {
 	struct kvm_zdev **kzdev;
 	spinlock_t gait_lock; /* Protects the gait, used during AEN forward */
 	struct mutex aift_lock; /* Protects the other structures in aift */
+	u32 mdd;
 };
 
 extern struct zpci_aift *aift;
@@ -48,6 +49,8 @@ static inline struct kvm *kvm_s390_pci_si_to_kvm(struct zpci_aift *aift,
 
 int kvm_s390_pci_aen_init(u8 nisc);
 void kvm_s390_pci_aen_exit(void);
+int kvm_s390_pci_refresh_trans(struct kvm_vcpu *vcpu, unsigned long req,
+			       unsigned long start, unsigned long end);
 
 int kvm_s390_pci_zpci_start(struct kvm *kvm, struct zpci_dev *zdev);
 int kvm_s390_pci_zpci_stop(struct kvm *kvm, struct zpci_dev *zdev);
-- 
2.27.0