[Qemu-devel] [PATCH 09/12] spapr-vio: move special case handling for reg=0 to vio

[Anthony Liguori]

The creatively named reg field is a hypervisor assigned global
identifier for a virtual device.  Despite the fact that no device
is assigned a reg of 0, guests still use it to refer to early
console.

Instead of handling this in the VTY device, handle this in the VIO
bus since this is ultimately about how devices are decoded.

This does not produce a change in behavior since reg=0 hcalls to
non-VTY devices will still fail as gloriously as they did before
just for a different reason (invalid device instead of invalid reg).

Signed-off-by: Anthony Liguori <address@hidden>
---
 hw/char/spapr_vty.c        | 58 ++--------------------------------------------
 hw/ppc/spapr_vio.c         | 46 ++++++++++++++++++++++++++++++++++++
 include/hw/ppc/spapr_vio.h |  2 --
 3 files changed, 48 insertions(+), 58 deletions(-)

diff --git a/hw/char/spapr_vty.c b/hw/char/spapr_vty.c
index 4bac79e..45fc3ce 100644
--- a/hw/char/spapr_vty.c
+++ b/hw/char/spapr_vty.c
@@ -86,23 +86,6 @@ static int spapr_vty_init(VIOsPAPRDevice *sdev)
     return 0;
 }
 
-static VIOsPAPRDevice *vty_lookup(sPAPREnvironment *spapr, target_ulong reg)
-{
-    VIOsPAPRDevice *sdev;
-
-    sdev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
-    if (!sdev && reg == 0) {
-        /* Hack for kernel early debug, which always specifies reg==0.
-         * We search all VIO devices, and grab the vty with the lowest
-         * reg.  This attempts to mimic existing PowerVM behaviour
-         * (early debug does work there, despite having no vty with
-         * reg==0. */
-        return spapr_vty_get_default(spapr->vio_bus);
-    }
-
-    return sdev;
-}
-
 /* Forward declaration */
 static target_ulong h_put_term_char(PowerPCCPU *cpu, sPAPREnvironment *spapr,
                                     target_ulong opcode, target_ulong *args)
@@ -114,7 +97,7 @@ static target_ulong h_put_term_char(PowerPCCPU *cpu, 
sPAPREnvironment *spapr,
     VIOsPAPRDevice *sdev;
     uint8_t buf[16];
 
-    sdev = vty_lookup(spapr, reg);
+    sdev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
     if (!sdev) {
         return H_PARAMETER;
     }
@@ -141,7 +124,7 @@ static target_ulong h_get_term_char(PowerPCCPU *cpu, 
sPAPREnvironment *spapr,
     VIOsPAPRDevice *sdev;
     uint8_t buf[16];
 
-    sdev = vty_lookup(spapr, reg);
+    sdev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
     if (!sdev) {
         return H_PARAMETER;
     }
@@ -191,43 +174,6 @@ static const TypeInfo spapr_vty_info = {
     .class_init    = spapr_vty_class_init,
 };
 
-VIOsPAPRDevice *spapr_vty_get_default(VIOsPAPRBus *bus)
-{
-    VIOsPAPRDevice *sdev, *selected;
-    BusChild *kid;
-
-    /*
-     * To avoid the console bouncing around we want one VTY to be
-     * the "default". We haven't really got anything to go on, so
-     * arbitrarily choose the one with the lowest reg value.
-     */
-
-    selected = NULL;
-    QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
-        DeviceState *iter = kid->child;
-
-        /* Only look at VTY devices */
-        if (!object_dynamic_cast(OBJECT(iter), "spapr-vty")) {
-            continue;
-        }
-
-        sdev = VIO_SPAPR_DEVICE(iter);
-
-        /* First VTY we've found, so it is selected for now */
-        if (!selected) {
-            selected = sdev;
-            continue;
-        }
-
-        /* Choose VTY with lowest reg value */
-        if (sdev->reg < selected->reg) {
-            selected = sdev;
-        }
-    }
-
-    return selected;
-}
-
 static void spapr_vty_register_types(void)
 {
     spapr_register_hypercall(H_PUT_TERM_CHAR, h_put_term_char);
diff --git a/hw/ppc/spapr_vio.c b/hw/ppc/spapr_vio.c
index 2c5b159..ee99eec 100644
--- a/hw/ppc/spapr_vio.c
+++ b/hw/ppc/spapr_vio.c
@@ -77,11 +77,57 @@ static const TypeInfo spapr_vio_bus_info = {
     .instance_size = sizeof(VIOsPAPRBus),
 };
 
+static VIOsPAPRDevice *spapr_vty_get_default(VIOsPAPRBus *bus)
+{
+    VIOsPAPRDevice *sdev, *selected;
+    BusChild *kid;
+
+    /*
+     * To avoid the console bouncing around we want one VTY to be
+     * the "default". We haven't really got anything to go on, so
+     * arbitrarily choose the one with the lowest reg value.
+     */
+
+    selected = NULL;
+    QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
+        DeviceState *iter = kid->child;
+
+        /* Only look at VTY devices */
+        if (!object_dynamic_cast(OBJECT(iter), "spapr-vty")) {
+            continue;
+        }
+
+        sdev = VIO_SPAPR_DEVICE(iter);
+
+        /* First VTY we've found, so it is selected for now */
+        if (!selected) {
+            selected = sdev;
+            continue;
+        }
+
+        /* Choose VTY with lowest reg value */
+        if (sdev->reg < selected->reg) {
+            selected = sdev;
+        }
+    }
+
+    return selected;
+}
+
 VIOsPAPRDevice *spapr_vio_find_by_reg(VIOsPAPRBus *bus, uint32_t reg)
 {
     BusChild *kid;
     VIOsPAPRDevice *dev = NULL;
 
+    /* Hack for kernel early debug, which always specifies reg==0.
+     * We search all VIO devices, and grab the vty with the lowest
+     * reg.  This attempts to mimic existing PowerVM behaviour
+     * (early debug does work there, despite having no vty with
+     * reg==0. */
+    if (reg == 0) {
+        return spapr_vty_get_default(bus);
+    }
+
     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
         dev = (VIOsPAPRDevice *)kid->child;
         if (dev->reg == reg) {
diff --git a/include/hw/ppc/spapr_vio.h b/include/hw/ppc/spapr_vio.h
index 817f5ff..f55eb90 100644
--- a/include/hw/ppc/spapr_vio.h
+++ b/include/hw/ppc/spapr_vio.h
@@ -127,8 +127,6 @@ void spapr_vty_create(VIOsPAPRBus *bus, CharDriverState 
*chardev);
 void spapr_vlan_create(VIOsPAPRBus *bus, NICInfo *nd);
 void spapr_vscsi_create(VIOsPAPRBus *bus);
 
-VIOsPAPRDevice *spapr_vty_get_default(VIOsPAPRBus *bus);
-
 void spapr_vio_quiesce(void);
 
 #endif /* _HW_SPAPR_VIO_H */
-- 
1.8.0