[RFC 8/8] s390x/pci: PCILG via the vfio zPCI I/O region

[Matthew Rosato <mjrosato@linux.ibm.com>]

For ISM devices, use the vfio region to handle intercepted PCILG
instructions.  This will allow read I/Os intercepted from the guest to be
performed as single operations that ensure the same non-MIO PCI instruction
is used on the host as specified in the guest.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
---
 hw/s390x/s390-pci-inst.c         |  3 ++-
 hw/s390x/s390-pci-vfio.c         | 53 ++++++++++++++++++++++++++++++++++++++++
 include/hw/s390x/s390-pci-inst.h |  1 +
 include/hw/s390x/s390-pci-vfio.h |  8 ++++++
 4 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c
index d4c79f6..33186dc 100644
--- a/hw/s390x/s390-pci-inst.c
+++ b/hw/s390x/s390-pci-inst.c
@@ -352,7 +352,7 @@ out:
  * @ptr: a pointer to a uint64_t data field
  * @len: the length of the valid data, must be 1,2,4 or 8
  */
-static int zpci_endian_swap(uint64_t *ptr, uint8_t len)
+int zpci_endian_swap(uint64_t *ptr, uint8_t len)
 {
     uint64_t data = *ptr;
 
@@ -1392,5 +1392,6 @@ void zpci_assign_default_ops(S390PCIBusDevice *pbdev)
 
 void zpci_assign_ops_vfio_io_region(S390PCIBusDevice *pbdev)
 {
+    pbdev->ops.pcilg = s390_pci_vfio_pcilg;
     pbdev->ops.pcistb = s390_pci_vfio_pcistb;
 }
diff --git a/hw/s390x/s390-pci-vfio.c b/hw/s390x/s390-pci-vfio.c
index ad50a62..baba6b0 100644
--- a/hw/s390x/s390-pci-vfio.c
+++ b/hw/s390x/s390-pci-vfio.c
@@ -337,6 +337,59 @@ int s390_pci_get_zpci_io_region(S390PCIBusDevice *pbdev)
     return ret;
 }
 
+int s390_pci_vfio_pcilg(S390PCIBusDevice *pbdev, uint64_t *data, uint8_t pcias,
+                        uint16_t len, uint64_t offset)
+{
+    struct vfio_region_zpci_io *region = pbdev->io_region;
+    VFIOPCIDevice *vfio_pci;
+    int ret;
+
+    if (region == NULL) {
+        return -EIO;
+    }
+
+    vfio_pci = container_of(pbdev->pdev, VFIOPCIDevice, pdev);
+
+    /* Perform Length/Alignment checks */
+    switch (pcias) {
+    case ZPCI_IO_BAR_MIN...ZPCI_IO_BAR_MAX:
+        if (!len || (len > (8 - (offset & 0x7)))) {
+            return -EINVAL;
+        }
+        region->req.gaddr = (uint64_t)data;
+        region->req.offset = offset;
+        region->req.len = len;
+        region->req.pcias = pcias;
+        region->req.flags = VFIO_ZPCI_IO_FLAG_READ;
+
+        ret = pwrite(vfio_pci->vbasedev.fd, &region->req,
+                     sizeof(struct vfio_zpci_io_req),
+                     pbdev->io_region_op_offset);
+        if (ret != sizeof(struct vfio_zpci_io_req)) {
+            ret = -EIO;
+        } else {
+            ret = 0;
+        }
+        break;
+    case ZPCI_CONFIG_BAR:
+        if (!len || (len > (4 - (offset & 0x3))) || len == 3) {
+            return -EINVAL;
+        }
+        *data = pci_host_config_read_common(
+                       pbdev->pdev, offset, pci_config_size(pbdev->pdev), len);
+
+        if (zpci_endian_swap(data, len)) {
+            ret = -EINVAL;
+        }
+        ret = 0;
+        break;
+    default:
+        return -EFAULT;
+    }
+
+    return ret;
+}
+
 int s390_pci_vfio_pcistb(S390PCIBusDevice *pbdev, S390CPU *cpu, uint64_t gaddr,
                          uint8_t ar, uint8_t pcias, uint16_t len,
                          uint64_t offset)
diff --git a/include/hw/s390x/s390-pci-inst.h b/include/hw/s390x/s390-pci-inst.h
index 7ed6175..fe368fb 100644
--- a/include/hw/s390x/s390-pci-inst.h
+++ b/include/hw/s390x/s390-pci-inst.h
@@ -101,6 +101,7 @@ typedef struct ZpciFib {
 int pci_dereg_irqs(S390PCIBusDevice *pbdev);
 void pci_dereg_ioat(S390PCIIOMMU *iommu);
 int clp_service_call(S390CPU *cpu, uint8_t r2, uintptr_t ra);
+int zpci_endian_swap(uint64_t *ptr, uint8_t len);
 int pcilg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2, uintptr_t ra);
 int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2, uintptr_t ra);
 int rpcit_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2, uintptr_t ra);
diff --git a/include/hw/s390x/s390-pci-vfio.h b/include/hw/s390x/s390-pci-vfio.h
index f0a994f..d9fb3a4 100644
--- a/include/hw/s390x/s390-pci-vfio.h
+++ b/include/hw/s390x/s390-pci-vfio.h
@@ -22,6 +22,8 @@ S390PCIDMACount *s390_pci_start_dma_count(S390pciState *s,
 void s390_pci_end_dma_count(S390pciState *s, S390PCIDMACount *cnt);
 void s390_pci_get_clp_info(S390PCIBusDevice *pbdev);
 int s390_pci_get_zpci_io_region(S390PCIBusDevice *pbdev);
+int s390_pci_vfio_pcilg(S390PCIBusDevice *pbdev, uint64_t *data, uint8_t pcias,
+                        uint16_t len, uint64_t offset);
 int s390_pci_vfio_pcistb(S390PCIBusDevice *pbdev, S390CPU *cpu, uint64_t gaddr,
                          uint8_t ar, uint8_t pcias, uint16_t len,
                          uint64_t offset);
@@ -42,6 +44,12 @@ static inline int s390_pci_get_zpci_io_region(S390PCIBusDevice *pbdev)
 {
     return -EINVAL;
 }
+static inline int s390_pci_vfio_pcilg(S390PCIBusDevice *pbdev, uint64_t *data,
+                                      uint8_t pcias, uint16_t len,
+                                      uint64_t offset)
+{
+    return -EIO;
+}
 static inline int s390_pci_vfio_pcistb(S390PCIBusDevice *pbdev, S390CPU *cpu,
                                        uint64_t gaddr, uint8_t ar,
                                        uint8_t pcias, uint16_t len,
-- 
1.8.3.1