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Subject[PATCH v4 23/32] KVM: s390: pci: provide routines for enabling/disabling interpretation
Date
These routines will be wired into a kvm ioctl in order to respond to
requests to enable / disable a device for zPCI Load/Store intepretation.

The first time such a request is received, enable the necessary facilities
for the guest.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
---
arch/s390/kvm/pci.c | 86 +++++++++++++++++++++++++++++++++++++++++++++
arch/s390/pci/pci.c | 3 ++
2 files changed, 89 insertions(+)

diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
index 28fe95f13c33..df50dd6114c3 100644
--- a/arch/s390/kvm/pci.c
+++ b/arch/s390/kvm/pci.c
@@ -13,7 +13,9 @@
#include <asm/kvm_pci.h>
#include <asm/pci.h>
#include <asm/pci_insn.h>
+#include <asm/sclp.h>
#include "pci.h"
+#include "kvm-s390.h"

struct zpci_aift *aift;

@@ -170,6 +172,87 @@ int kvm_s390_pci_aen_init(u8 nisc)
return rc;
}

+static int kvm_s390_pci_interp_enable(struct zpci_dev *zdev)
+{
+ u32 gisa;
+ int rc;
+
+ if (!zdev->kzdev || !zdev->kzdev->kvm)
+ return -EINVAL;
+
+ /*
+ * If this is the first request to use an interpreted device, make the
+ * necessary vcpu changes
+ */
+ if (!zdev->kzdev->kvm->arch.use_zpci_interp)
+ kvm_s390_vcpu_pci_enable_interp(zdev->kzdev->kvm);
+
+ /*
+ * In the event of a system reset in userspace, the GISA designation
+ * may still be assigned because the device is still enabled.
+ * Verify it's the same guest before proceeding.
+ */
+ gisa = (u32)virt_to_phys(&zdev->kzdev->kvm->arch.sie_page2->gisa);
+ if (zdev->gisa != 0 && zdev->gisa != gisa)
+ return -EPERM;
+
+ if (zdev_enabled(zdev)) {
+ zdev->gisa = 0;
+ rc = zpci_disable_device(zdev);
+ if (rc)
+ return rc;
+ }
+
+ /*
+ * Store information about the identity of the kvm guest allowed to
+ * access this device via interpretation to be used by host CLP
+ */
+ zdev->gisa = gisa;
+
+ rc = zpci_enable_device(zdev);
+ if (rc)
+ goto err;
+
+ /* Re-register the IOMMU that was already created */
+ rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
+ virt_to_phys(zdev->dma_table));
+ if (rc)
+ goto err;
+
+ return rc;
+
+err:
+ zdev->gisa = 0;
+ return rc;
+}
+
+static int kvm_s390_pci_interp_disable(struct zpci_dev *zdev)
+{
+ int rc;
+
+ if (zdev->gisa == 0)
+ return -EINVAL;
+
+ /* Remove the host CLP guest designation */
+ zdev->gisa = 0;
+
+ if (zdev_enabled(zdev)) {
+ rc = zpci_disable_device(zdev);
+ if (rc)
+ return rc;
+ }
+
+ rc = zpci_enable_device(zdev);
+ if (rc)
+ return rc;
+
+ /* Re-register the IOMMU that was already created */
+ rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
+ virt_to_phys(zdev->dma_table));
+
+ return rc;
+}
+
static int kvm_s390_pci_group_notifier(struct notifier_block *nb,
unsigned long action, void *data)
{
@@ -203,6 +286,9 @@ void kvm_s390_pci_dev_release(struct zpci_dev *zdev)
{
struct kvm_zdev *kzdev;

+ if (zdev->gisa != 0)
+ kvm_s390_pci_interp_disable(zdev, true);
+
kzdev = zdev->kzdev;
WARN_ON(kzdev->zdev != zdev);
zdev->kzdev = 0;
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 13033717cd4e..5dbe49ec325e 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -147,6 +147,7 @@ int zpci_register_ioat(struct zpci_dev *zdev, u8 dmaas,
zpci_dbg(3, "reg ioat fid:%x, cc:%d, status:%d\n", zdev->fid, cc, status);
return cc;
}
+EXPORT_SYMBOL_GPL(zpci_register_ioat);

/* Modify PCI: Unregister I/O address translation parameters */
int zpci_unregister_ioat(struct zpci_dev *zdev, u8 dmaas)
@@ -727,6 +728,7 @@ int zpci_enable_device(struct zpci_dev *zdev)
zpci_update_fh(zdev, fh);
return rc;
}
+EXPORT_SYMBOL_GPL(zpci_enable_device);

int zpci_disable_device(struct zpci_dev *zdev)
{
@@ -750,6 +752,7 @@ int zpci_disable_device(struct zpci_dev *zdev)
}
return rc;
}
+EXPORT_SYMBOL_GPL(zpci_disable_device);

/**
* zpci_hot_reset_device - perform a reset of the given zPCI function
--
2.27.0
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