[Qemu-devel] [QEMU][RFC V2 10/10] xen: emulate IDE outside default device set

[Julien Grall]

IDE can be emulate in a different QEMU that the default.

This patch also fixes ide_get_geometry. When QEMU didn't emulate IDE,
it try to derefence a NULL bus.

Signed-off-by: Julien Grall <julien.gr...@citrix.com>
---
 hw/ide/qdev.c |    8 +++++++-
 hw/pc_piix.c  |   38 ++++++++++++++++++++++++--------------
 hw/xen.h      |   10 ++++++++++
 xen-all.c     |    8 +++++++-
 4 files changed, 48 insertions(+), 16 deletions(-)

diff --git a/hw/ide/qdev.c b/hw/ide/qdev.c
index 5ea9b8f..473acd7 100644
--- a/hw/ide/qdev.c
+++ b/hw/ide/qdev.c
@@ -115,7 +115,13 @@ IDEDevice *ide_create_drive(IDEBus *bus, int unit, 
DriveInfo *drive)
 int ide_get_geometry(BusState *bus, int unit,
                      int16_t *cyls, int8_t *heads, int8_t *secs)
 {
-    IDEState *s = &DO_UPCAST(IDEBus, qbus, bus)->ifs[unit];
+    IDEState *s = NULL;
+
+    if (!bus) {
+        return -1;
+    }
+
+    s = &DO_UPCAST(IDEBus, qbus, bus)->ifs[unit];
 
     if (s->drive_kind != IDE_HD || !s->bs) {
         return -1;
diff --git a/hw/pc_piix.c b/hw/pc_piix.c
index 6cb0a2a..b904100 100644
--- a/hw/pc_piix.c
+++ b/hw/pc_piix.c
@@ -148,6 +148,7 @@ static void pc_init1(MemoryRegion *system_memory,
     MemoryRegion *pci_memory;
     MemoryRegion *rom_memory;
     void *fw_cfg = NULL;
+    int register_default_dev = 0;
 
     pc_cpus_init(cpu_model);
 
@@ -242,23 +243,32 @@ static void pc_init1(MemoryRegion *system_memory,
             pci_nic_init_nofail(nd, "e1000", NULL);
     }
 
-    ide_drive_get(hd, MAX_IDE_BUS);
-    if (pci_enabled) {
-        PCIDevice *dev;
-        if (xen_enabled()) {
-            dev = pci_piix3_xen_ide_init(pci_bus, hd, piix3_devfn + 1);
+    if (!xen_enabled() || xen_is_emulated_ide()) {
+        xen_set_register_default_dev(0, &register_default_dev);
+        ide_drive_get(hd, MAX_IDE_BUS);
+        if (pci_enabled) {
+            PCIDevice *dev;
+            if (xen_enabled()) {
+                dev = pci_piix3_xen_ide_init(pci_bus, hd, piix3_devfn + 1);
+            } else {
+                dev = pci_piix3_ide_init(pci_bus, hd, piix3_devfn + 1);
+            }
+            idebus[0] = qdev_get_child_bus(&dev->qdev, "ide.0");
+            idebus[1] = qdev_get_child_bus(&dev->qdev, "ide.1");
         } else {
-            dev = pci_piix3_ide_init(pci_bus, hd, piix3_devfn + 1);
+            for (i = 0; i < MAX_IDE_BUS; i++) {
+                ISADevice *dev;
+                dev = isa_ide_init(isa_bus, ide_iobase[i], ide_iobase2[i],
+                                   ide_irq[i],
+                                   hd[MAX_IDE_DEVS * i],
+                                   hd[MAX_IDE_DEVS * i + 1]);
+                idebus[i] = qdev_get_child_bus(&dev->qdev, "ide.0");
+            }
         }
-        idebus[0] = qdev_get_child_bus(&dev->qdev, "ide.0");
-        idebus[1] = qdev_get_child_bus(&dev->qdev, "ide.1");
+        xen_set_register_default_dev(register_default_dev, NULL);
     } else {
-        for(i = 0; i < MAX_IDE_BUS; i++) {
-            ISADevice *dev;
-            dev = isa_ide_init(isa_bus, ide_iobase[i], ide_iobase2[i],
-                               ide_irq[i],
-                               hd[MAX_IDE_DEVS * i], hd[MAX_IDE_DEVS * i + 1]);
-            idebus[i] = qdev_get_child_bus(&dev->qdev, "ide.0");
+        for (i = 0; i < MAX_IDE_BUS; i++) {
+            idebus[i] = NULL;
         }
     }
 
diff --git a/hw/xen.h b/hw/xen.h
index 3c8724f..3c89fb9 100644
--- a/hw/xen.h
+++ b/hw/xen.h
@@ -22,6 +22,7 @@ extern enum xen_mode xen_mode;
 
 extern int xen_allowed;
 extern int xen_register_default_dev;
+extern int xen_emulate_ide;
 
 static inline int xen_enabled(void)
 {
@@ -32,6 +33,15 @@ static inline int xen_enabled(void)
 #endif
 }
 
+static inline int xen_is_emulated_ide(void)
+{
+#if defined(CONFIG_XEN)
+    return xen_emulate_ide;
+#else
+    return 1;
+#endif
+}
+
 static inline int xen_is_registered_default_dev(void)
 {
 #if defined(CONFIG_XEN)
diff --git a/xen-all.c b/xen-all.c
index f424cce..f091908 100644
--- a/xen-all.c
+++ b/xen-all.c
@@ -43,6 +43,8 @@ static uint32_t xen_dmid = ~0;
 int xen_register_default_dev = 0;
 static int xen_emulate_default_dev = 1;
 
+int xen_emulate_ide = 0;
+
 /* Compatibility with older version */
 #if __XEN_LATEST_INTERFACE_VERSION__ < 0x0003020a
 static inline uint32_t xen_vcpu_eport(shared_iopage_t *shared_page, int i)
@@ -1342,6 +1344,8 @@ int xen_hvm_init(void)
                                        "xen_dmid", ~0);
         xen_emulate_default_dev = qemu_opt_get_bool(QTAILQ_FIRST(&list->head),
                                                     "xen_default_dev", 1);
+        xen_emulate_ide = qemu_opt_get_bool(QTAILQ_FIRST(&list->head),
+                                            "xen_emulate_ide", 1);
     }
 
     state = g_malloc0(sizeof (XenIOState));
@@ -1437,12 +1441,14 @@ int xen_hvm_init(void)
         fprintf(stderr, "%s: xen backend core setup failed\n", __FUNCTION__);
         exit(1);
     }
-    xen_be_register("qdisk", &xen_blkdev_ops);
 
     if (xen_emulate_default_dev) {
         xen_be_register("console", &xen_console_ops);
         xen_be_register("vkbd", &xen_kbdmouse_ops);
     }
+    if (xen_emulate_ide) {
+        xen_be_register("qdisk", &xen_blkdev_ops);
+    }
     xen_read_physmap(state);
 
     return 0;
-- 
Julien Grall