[PATCH v2 18/30] KVM: s390: pci: provide routines for enabling/disabling interpretation

Matthew Rosato
2022-01-14T20:33:35Z

These routines will be wired into the vfio_pci_zdev ioctl handlers to
respond to requests to enable / disable a device for zPCI Load/Store
interpretation.

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/include/asm/kvm_pci.h | 4 ++
arch/s390/kvm/pci.c | 99 +++++++++++++++++++++++++++++++++
arch/s390/pci/pci.c | 3 +
3 files changed, 106 insertions(+)

diff --git a/arch/s390/include/asm/kvm_pci.h b/arch/s390/include/asm/kvm_pci.h
index aafee2976929..072401aa7922 100644
--- a/arch/s390/include/asm/kvm_pci.h
+++ b/arch/s390/include/asm/kvm_pci.h
@@ -26,4 +26,8 @@ int kvm_s390_pci_dev_open(struct zpci_dev *zdev);
void kvm_s390_pci_dev_release(struct zpci_dev *zdev);
void kvm_s390_pci_attach_kvm(struct zpci_dev *zdev, struct kvm *kvm);

+int kvm_s390_pci_interp_probe(struct zpci_dev *zdev);
+int kvm_s390_pci_interp_enable(struct zpci_dev *zdev);
+int kvm_s390_pci_interp_disable(struct zpci_dev *zdev);
+
#endif /* ASM_KVM_PCI_H */
diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
index dae853da6df1..122d0992b521 100644
--- a/arch/s390/kvm/pci.c
+++ b/arch/s390/kvm/pci.c
@@ -12,7 +12,9 @@
#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;

@@ -143,6 +145,103 @@ int kvm_s390_pci_aen_init(u8 nisc)
return rc;
}

+int kvm_s390_pci_interp_probe(struct zpci_dev *zdev)
+{
+ /* Must have appropriate hardware facilities */
+ if (!(sclp.has_zpci_lsi && test_facility(69)))
+ return -EINVAL;
+
+ /* Must have a KVM association registered */
+ if (!zdev->kzdev || !zdev->kzdev->kvm)
+ return -EINVAL;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_s390_pci_interp_probe);
+
+int kvm_s390_pci_interp_enable(struct zpci_dev *zdev)
+{
+ u32 gd;
+ 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.
+ */
+ gd = (u32)(u64)&zdev->kzdev->kvm->arch.sie_page2->gisa;
+ if (zdev->gd != 0 && zdev->gd != gd)
+ return -EPERM;
+
+ if (zdev_enabled(zdev)) {
+ zdev->gd = 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->gd = gd;
+
+ 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->gd = 0;
+ return rc;
+}
+EXPORT_SYMBOL_GPL(kvm_s390_pci_interp_enable);
+
+int kvm_s390_pci_interp_disable(struct zpci_dev *zdev)
+{
+ int rc;
+
+ if (zdev->gd == 0)
+ return -EINVAL;
+
+ /* Remove the host CLP guest designation */
+ zdev->gd = 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;
+}
+EXPORT_SYMBOL_GPL(kvm_s390_pci_interp_disable);
+
int kvm_s390_pci_dev_open(struct zpci_dev *zdev)
{
struct kvm_zdev *kzdev;
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 2a19becbc14c..58673f633869 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