xen/pci: Add hypercall to support reset of pcidev

When a device has been reset on dom0 side, the Xen hypervisor
doesn't get notification, so the cached state in vpci is all
out of date compare with the real device state.

To solve that problem, add a new hypercall to support the reset
of pcidev and clear the vpci state of device. So that once the
state of device is reset on dom0 side, dom0 can call this
hypercall to notify hypervisor.

The behavior of different reset types may be different in the
future, so divide them now so that they can be easily modified
in the future without affecting the hypercall interface.

Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>

xen/arch/x86/hvm/hypercall.c

@@ -84,6 +84,7 @@ long hvm_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
     case PHYSDEVOP_pci_mmcfg_reserved:
     case PHYSDEVOP_pci_device_add:
     case PHYSDEVOP_pci_device_remove:
+    case PHYSDEVOP_pci_device_reset:
     case PHYSDEVOP_dbgp_op:
         if ( !is_hardware_domain(currd) )
             return -ENOSYS;

xen/drivers/pci/physdev.c

@@ -2,6 +2,7 @@
 #include <xen/guest_access.h>
 #include <xen/hypercall.h>
 #include <xen/init.h>
+#include <xen/vpci.h>
 
 #ifndef COMPAT
 typedef long ret_t;
@@ -67,6 +68,57 @@ ret_t pci_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
         break;
     }
 
+    case PHYSDEVOP_pci_device_reset:
+    {
+        struct pci_device_reset dev_reset;
+        struct pci_dev *pdev;
+        pci_sbdf_t sbdf;
+
+        ret = -EFAULT;
+        if ( copy_from_guest(&dev_reset, arg, 1) != 0 )
+            break;
+
+        ret = -EINVAL;
+        if ( dev_reset.flags & ~PCI_DEVICE_RESET_MASK )
+            break;
+
+        sbdf = PCI_SBDF(dev_reset.dev.seg,
+                        dev_reset.dev.bus,
+                        dev_reset.dev.devfn);
+
+        ret = xsm_resource_setup_pci(XSM_PRIV, sbdf.sbdf);
+        if ( ret )
+            break;
+
+        pcidevs_lock();
+        pdev = pci_get_pdev(NULL, sbdf);
+        if ( !pdev )
+        {
+            pcidevs_unlock();
+            ret = -ENODEV;
+            break;
+        }
+
+        write_lock(&pdev->domain->pci_lock);
+        pcidevs_unlock();
+        switch ( dev_reset.flags & PCI_DEVICE_RESET_MASK )
+        {
+        case PCI_DEVICE_RESET_COLD:
+        case PCI_DEVICE_RESET_WARM:
+        case PCI_DEVICE_RESET_HOT:
+        case PCI_DEVICE_RESET_FLR:
+            ret = vpci_reset_device(pdev);
+            break;
+
+        default:
+            ret = -EINVAL;
+            break;
+        }
+        write_unlock(&pdev->domain->pci_lock);
+
+        break;
+    }
+
     default:
         ret = -ENOSYS;
         break;

xen/include/public/physdev.h

@@ -296,6 +296,13 @@ DEFINE_XEN_GUEST_HANDLE(physdev_pci_device_add_t);
  */
 #define PHYSDEVOP_prepare_msix          30
 #define PHYSDEVOP_release_msix          31
+/*
+ * Notify the hypervisor that a PCI device has been reset, so that any
+ * internally cached state is regenerated.  Should be called after any
+ * device reset performed by the hardware domain.
+ */
+#define PHYSDEVOP_pci_device_reset      32
+
 struct physdev_pci_device {
     /* IN */
     uint16_t seg;
@@ -305,6 +312,16 @@ struct physdev_pci_device {
 typedef struct physdev_pci_device physdev_pci_device_t;
 DEFINE_XEN_GUEST_HANDLE(physdev_pci_device_t);
 
+struct pci_device_reset {
+    physdev_pci_device_t dev;
+#define PCI_DEVICE_RESET_COLD 0x0
+#define PCI_DEVICE_RESET_WARM 0x1
+#define PCI_DEVICE_RESET_HOT  0x2
+#define PCI_DEVICE_RESET_FLR  0x3
+#define PCI_DEVICE_RESET_MASK 0x3
+    uint32_t flags;
+};
+
 #define PHYSDEVOP_DBGP_RESET_PREPARE    1
 #define PHYSDEVOP_DBGP_RESET_DONE       2
 

xen/include/xen/vpci.h

@@ -304,6 +304,12 @@ static inline bool __must_check vpci_process_pending(struct vcpu *v)
 }
 #endif
 
+static inline int __must_check vpci_reset_device(struct pci_dev *pdev)
+{
+    vpci_deassign_device(pdev);
+    return vpci_assign_device(pdev);
+}
+
 #endif
 
 /*