pc: get rid of builtin pvpanic for "-M pc-1.5"

This causes two slight backwards-incompatibilities between "-M pc-1.5"
and 1.5's "-M pc":

(1) a fw_cfg file is removed with this patch.  This is only a problem
if migration stops the virtual machine exactly during fw_cfg enumeration.

(2) after migration, a VM created without an explicit "-device pvpanic"
will stop reporting panics to management.

The first problem only occurs if migration is done at a very, very
early point (and I'm not sure it can happen in practice for reasonable-size
VMs, since it will likely take more time to send the RAM to destination,
than it will take for BIOS to scan fw_cfg).

The second problem only occurs if the guest panics _and_ has a guest
driver _and_ management knows to look at the crash event, so it is
mostly theoretical at this point in time.

Thus keep the code simple, and pretend it was never broken.
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

hw/i386/pc_piix.c

@@ -57,7 +57,6 @@ static const int ide_iobase[MAX_IDE_BUS] = { 0x1f0, 0x170 };
 static const int ide_iobase2[MAX_IDE_BUS] = { 0x3f6, 0x376 };
 static const int ide_irq[MAX_IDE_BUS] = { 14, 15 };
 
-static bool has_pvpanic;
 static bool has_pci_info;
 static bool has_acpi_build = true;
 
@@ -229,10 +228,6 @@ static void pc_init1(QEMUMachineInitArgs *args,
     if (pci_enabled) {
         pc_pci_device_init(pci_bus);
     }
-
-    if (has_pvpanic) {
-        pvpanic_init(isa_bus);
-    }
 }
 
 static void pc_init_pci(QEMUMachineInitArgs *args)
@@ -250,13 +245,11 @@ static void pc_compat_1_6(QEMUMachineInitArgs *args)
 static void pc_compat_1_5(QEMUMachineInitArgs *args)
 {
     pc_compat_1_6(args);
-    has_pvpanic = true;
 }
 
 static void pc_compat_1_4(QEMUMachineInitArgs *args)
 {
     pc_compat_1_5(args);
-    has_pvpanic = false;
     x86_cpu_compat_set_features("n270", FEAT_1_ECX, 0, CPUID_EXT_MOVBE);
     x86_cpu_compat_set_features("Westmere", FEAT_1_ECX, 0, CPUID_EXT_PCLMULQDQ);
 }

hw/i386/pc_q35.c

@@ -47,7 +47,6 @@
 /* ICH9 AHCI has 6 ports */
 #define MAX_SATA_PORTS     6
 
-static bool has_pvpanic;
 static bool has_pci_info;
 static bool has_acpi_build = true;
 
@@ -216,10 +215,6 @@ static void pc_q35_init(QEMUMachineInitArgs *args)
     if (pci_enabled) {
         pc_pci_device_init(host_bus);
     }
-
-    if (has_pvpanic) {
-        pvpanic_init(isa_bus);
-    }
 }
 
 static void pc_compat_1_6(QEMUMachineInitArgs *args)
@@ -232,13 +227,11 @@ static void pc_compat_1_6(QEMUMachineInitArgs *args)
 static void pc_compat_1_5(QEMUMachineInitArgs *args)
 {
     pc_compat_1_6(args);
-    has_pvpanic = true;
 }
 
 static void pc_compat_1_4(QEMUMachineInitArgs *args)
 {
     pc_compat_1_5(args);
-    has_pvpanic = false;
     x86_cpu_compat_set_features("n270", FEAT_1_ECX, 0, CPUID_EXT_MOVBE);
     x86_cpu_compat_set_features("Westmere", FEAT_1_ECX, 0, CPUID_EXT_PCLMULQDQ);
 }

hw/misc/pvpanic.c

@@ -112,11 +112,6 @@ static void pvpanic_isa_realizefn(DeviceState *dev, Error **errp)
     isa_register_ioport(d, &s->io, s->ioport);
 }
 
-void pvpanic_init(ISABus *bus)
-{
-    isa_create_simple(bus, TYPE_ISA_PVPANIC_DEVICE);
-}
-
 #define PVPANIC_IOPORT_PROP "ioport"
 
 uint16_t pvpanic_port(void)

include/hw/i386/pc.h

@@ -235,7 +235,6 @@ void pc_system_firmware_init(MemoryRegion *rom_memory,
                              bool isapc_ram_fw);
 
 /* pvpanic.c */
-void pvpanic_init(ISABus *bus);
 uint16_t pvpanic_port(void);
 
 /* e820 types */