On 27/05/2015 23:06, Laszlo Ersek wrote: > It is Very annoying to carry forward an outdatEd coNtroller with a mOdern > Machine type. > > Hence, let us not instantiate the FDC when all of the following apply: > - the machine type is pc-q35-2.4 or later, > - "-device isa-fdc" is not passed on the command line (nor in the config > file), > - no "-drive if=floppy,..." is requested. > > The first part of the code flow, updated by the patch, is as follows: > > 1. The "no_floppy = 1" machine class setting causes "default_floppy" in > main() to become zero. > > 2. Hence default_drive() will not call drive_add() and drive_new() for > IF_FLOPPY, index=0. > > This alone would not suffice, because the pc_basic_device_init() function > creates the FDC regardless of actual floppy drives. Therefore, > > 3. pc_basic_device_init() should only create the FDC if that's desirable > for the platform (= all PIIX types, and Q35 types earlier than 2.4), > *or* the user requested at least one IF_FLOPPY drive. > > 4. If the FDC is not created, callers of pc_basic_device_init() -- > pc_q35_init() and pc_init1() -- will pass floppy=NULL to > pc_cmos_init(). Luckily, pc_cmos_init() already handles that case. > > I verified the patch under the following scenarios, with "info qtree" and > with the MAP command of the UEFI shell (in OVMF): > - "pc" machine type -- no changes, FDC present, > - "pc-q35-2.3" machine type -- no changes, FDC present, > - "pc-q35" machine type with "-device isa-fdc" -- no changes, FDC present, > - "pc-q35" machine type with "-drive if=floppy,..." -- no changes, FDC > present, > - "pc-q35" -- no FDC. > > Suggested-by: Markus Armbruster <arm...@redhat.com> > Cc: Markus Armbruster <arm...@redhat.com> > Cc: Paolo Bonzini <pbonz...@redhat.com> > Cc: "Michael S. Tsirkin" <m...@redhat.com> > Signed-off-by: Laszlo Ersek <ler...@redhat.com> > --- > include/hw/i386/pc.h | 1 + > hw/i386/pc.c | 4 +++- > hw/i386/pc_piix.c | 2 +- > hw/i386/pc_q35.c | 12 +++++++++--- > 4 files changed, 14 insertions(+), 5 deletions(-) > > diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h > index 1b35168..55522b7 100644 > --- a/include/hw/i386/pc.h > +++ b/include/hw/i386/pc.h > @@ -199,6 +199,7 @@ qemu_irq *pc_allocate_cpu_irq(void); > DeviceState *pc_vga_init(ISABus *isa_bus, PCIBus *pci_bus); > void pc_basic_device_init(ISABus *isa_bus, qemu_irq *gsi, > ISADevice **rtc_state, > + bool force_fdctrl, > ISADevice **floppy, > bool no_vmport, > uint32 hpet_irqs); > diff --git a/hw/i386/pc.c b/hw/i386/pc.c > index 769eb25..b77d9b4 100644 > --- a/hw/i386/pc.c > +++ b/hw/i386/pc.c > @@ -1395,6 +1395,7 @@ static const MemoryRegionOps ioportF0_io_ops = { > > void pc_basic_device_init(ISABus *isa_bus, qemu_irq *gsi, > ISADevice **rtc_state, > + bool force_fdctrl, > ISADevice **floppy, > bool no_vmport, > uint32 hpet_irqs) > @@ -1489,8 +1490,9 @@ void pc_basic_device_init(ISABus *isa_bus, qemu_irq > *gsi, > > for(i = 0; i < MAX_FD; i++) { > fd[i] = drive_get(IF_FLOPPY, 0, i); > + force_fdctrl |= !!fd[i]; > } > - *floppy = fdctrl_init_isa(isa_bus, fd); > + *floppy = force_fdctrl ? fdctrl_init_isa(isa_bus, fd) : NULL; > } > > void pc_nic_init(ISABus *isa_bus, PCIBus *pci_bus) > diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c > index 212e263..9f530c4 100644 > --- a/hw/i386/pc_piix.c > +++ b/hw/i386/pc_piix.c > @@ -242,7 +242,7 @@ static void pc_init1(MachineState *machine, > } > > /* init basic PC hardware */ > - pc_basic_device_init(isa_bus, gsi, &rtc_state, &floppy, > + pc_basic_device_init(isa_bus, gsi, &rtc_state, true, &floppy, > (pc_machine->vmport != ON_OFF_AUTO_ON), 0x4); > > pc_nic_init(isa_bus, pci_bus); > diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c > index e67f2de..4d68340 100644 > --- a/hw/i386/pc_q35.c > +++ b/hw/i386/pc_q35.c > @@ -60,6 +60,7 @@ static bool smbios_uuid_encoded = true; > */ > static bool gigabyte_align = true; > static bool has_reserved_memory = true; > +static bool force_fdctrl; > > /* PC hardware initialisation */ > static void pc_q35_init(MachineState *machine) > @@ -250,7 +251,7 @@ static void pc_q35_init(MachineState *machine) > } > > /* init basic PC hardware */ > - pc_basic_device_init(isa_bus, gsi, &rtc_state, &floppy, > + pc_basic_device_init(isa_bus, gsi, &rtc_state, force_fdctrl, &floppy, > (pc_machine->vmport != ON_OFF_AUTO_ON), 0xff0104); > > /* connect pm stuff to lpc */ > @@ -291,6 +292,7 @@ static void pc_q35_init(MachineState *machine) > > static void pc_compat_2_3(MachineState *machine) > { > + force_fdctrl = true; > } > > static void pc_compat_2_2(MachineState *machine) > @@ -424,7 +426,8 @@ static void pc_q35_init_1_4(MachineState *machine) > #define PC_Q35_2_4_MACHINE_OPTIONS \ > PC_Q35_MACHINE_OPTIONS, \ > .default_machine_opts = "firmware=bios-256k.bin", \ > - .default_display = "std" > + .default_display = "std", \ > + .no_floppy = 1 > > static QEMUMachine pc_q35_machine_v2_4 = { > PC_Q35_2_4_MACHINE_OPTIONS, > @@ -433,7 +436,10 @@ static QEMUMachine pc_q35_machine_v2_4 = { > .init = pc_q35_init, > }; > > -#define PC_Q35_2_3_MACHINE_OPTIONS PC_Q35_2_4_MACHINE_OPTIONS > +#define PC_Q35_2_3_MACHINE_OPTIONS \ > + PC_Q35_MACHINE_OPTIONS, \ > + .default_machine_opts = "firmware=bios-256k.bin", \ > + .default_display = "std" > > static QEMUMachine pc_q35_machine_v2_3 = { > PC_Q35_2_3_MACHINE_OPTIONS, >
Acked-by: Paolo Bonzini <pbonz...@redhat.com>