[Qemu-devel] [PATCH 3/6] pc/vl: Add units-per-default-bus property

[John Snow <jsnow@redhat.com>]

This patch adds the 'units_per_default_bus' property
which allows individual boards to declare their desired
index => (bus,unit) mapping for their default HBA, so
that boards such as Q35 can specify that its default
if_ide HBA, AHCI, only accepts one unit per bus.

This property only overrides the mapping for drives
matching the block_default_type interface.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 hw/i386/pc.c        | 1 +
 hw/i386/pc_q35.c    | 3 ++-
 include/hw/boards.h | 2 ++
 vl.c                | 8 ++++++++
 4 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 2c2e9dc..ab578bf 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1524,6 +1524,7 @@ static void pc_generic_machine_class_init(ObjectClass *oc, void *data)
     mc->hot_add_cpu = qm->hot_add_cpu;
     mc->kvm_type = qm->kvm_type;
     mc->block_default_type = qm->block_default_type;
+    mc->units_per_default_bus = qm->units_per_default_bus;
     mc->max_cpus = qm->max_cpus;
     mc->no_serial = qm->no_serial;
     mc->no_parallel = qm->no_parallel;
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index d4a907c..b28ddbb 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -344,7 +344,8 @@ static void pc_q35_init_1_4(MachineState *machine)
 #define PC_Q35_MACHINE_OPTIONS \
     PC_DEFAULT_MACHINE_OPTIONS, \
     .desc = "Standard PC (Q35 + ICH9, 2009)", \
-    .hot_add_cpu = pc_hot_add_cpu
+    .hot_add_cpu = pc_hot_add_cpu, \
+    .units_per_default_bus = 1
 
 #define PC_Q35_2_2_MACHINE_OPTIONS                      \
     PC_Q35_MACHINE_OPTIONS,                             \
diff --git a/include/hw/boards.h b/include/hw/boards.h
index dfb6718..663f16a 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -28,6 +28,7 @@ struct QEMUMachine {
     QEMUMachineHotAddCPUFunc *hot_add_cpu;
     QEMUMachineGetKvmtypeFunc *kvm_type;
     BlockInterfaceType block_default_type;
+    int units_per_default_bus;
     int max_cpus;
     unsigned int no_serial:1,
         no_parallel:1,
@@ -86,6 +87,7 @@ struct MachineClass {
     int (*kvm_type)(const char *arg);
 
     BlockInterfaceType block_default_type;
+    int units_per_default_bus;
     int max_cpus;
     unsigned int no_serial:1,
         no_parallel:1,
diff --git a/vl.c b/vl.c
index eaef240..6fffa1f 100644
--- a/vl.c
+++ b/vl.c
@@ -1588,6 +1588,7 @@ static void machine_class_init(ObjectClass *oc, void *data)
     mc->hot_add_cpu = qm->hot_add_cpu;
     mc->kvm_type = qm->kvm_type;
     mc->block_default_type = qm->block_default_type;
+    mc->units_per_default_bus = qm->units_per_default_bus;
     mc->max_cpus = qm->max_cpus;
     mc->no_serial = qm->no_serial;
     mc->no_parallel = qm->no_parallel;
@@ -4377,6 +4378,13 @@ int main(int argc, char **argv, char **envp)
     blk_mig_init();
     ram_mig_init();
 
+    /* If the currently selected machine wishes to override the units-per-bus
+     * property of its default HBA interface type, do so now. */
+    if (machine_class->units_per_default_bus) {
+        override_max_devs(machine_class->block_default_type,
+                          machine_class->units_per_default_bus);
+    }
+
     /* open the virtual block devices */
     if (snapshot)
         qemu_opts_foreach(qemu_find_opts("drive"), drive_enable_snapshot, NULL, 0);
-- 
1.9.3