Re: [Qemu-devel] [RFC] in-kernel irqchip : split devices

[Glauber Costa <glommer@gmail.com>]

Specially Avi,

comments on this one?

2009/10/14 Glauber Costa <glommer@redhat.com>:
> Hello people,
>
> As I promised, I am sending a very brief PoC wrt split devices and in-kernel irqchip.
> In this mail, I am including only the ioapic version for apreciation. I also have i8259,
> and apic will take me a little bit more. This is just to try to bind the discussion to real
> code.
>
> Note that we end up with a very slim representation of the device, and the code is much less
> confusing, IMHO.
>
>
>
> Index: qemu/Makefile.target
> ===================================================================
> --- qemu.orig/Makefile.target
> +++ qemu/Makefile.target
> @@ -197,6 +197,8 @@ obj-i386-y += usb-uhci.o vmmouse.o vmpor
>  obj-i386-y += device-hotplug.o pci-hotplug.o smbios.o wdt_ib700.o
>  obj-i386-y += ne2000-isa.o
>
> +obj-i386-$(CONFIG_KVM) += ioapic-kvm.o
> +
>  # shared objects
>  obj-ppc-y = ppc.o ide/core.o ide/qdev.o ide/isa.o ide/pci.o ide/macio.o
>  obj-ppc-y += vga.o vga-pci.o $(sound-obj-y) dma.o openpic.o
> Index: qemu/hw/ioapic-kvm.c
> ===================================================================
> --- /dev/null
> +++ qemu/hw/ioapic-kvm.c
> @@ -0,0 +1,81 @@
> +#include "hw.h"
> +#include "pc.h"
> +#include "qemu-timer.h"
> +#include "host-utils.h"
> +#include "kvm.h"
> +
> +#define IOAPIC_NUM_PINS                        0x18
> +#define IOAPIC_DEFAULT_BASE_ADDRESS  0xfec00000
> +
> +static void ioapic_reset(void *opaque)
> +{
> +    struct kvm_ioapic_state *s = opaque;
> +    struct kvm_irqchip *chip;
> +    int i;
> +
> +    chip = container_of(s, struct kvm_irqchip, chip.ioapic);
> +
> +    chip->chip_id = KVM_IRQCHIP_IOAPIC;
> +
> +    memset(s, 0, sizeof(*s));
> +    s->base_address = IOAPIC_DEFAULT_BASE_ADDRESS;
> +    for(i = 0; i < IOAPIC_NUM_PINS; i++)
> +        s->redirtbl[i].bits = 1 << 16; /* mask LVT */
> +
> +    kvm_set_irqchip(chip);
> +}
> +
> +static void ioapic_pre_save(void *opaque)
> +{
> +    struct kvm_ioapic_state *s = opaque;
> +    struct kvm_irqchip *chip;
> +
> +    chip = container_of(s, struct kvm_irqchip, chip.ioapic);
> +
> +    kvm_get_irqchip(chip);
> +}
> +
> +static int ioapic_post_load(void *opaque, int version_id)
> +{
> +    struct kvm_ioapic_state *s = opaque;
> +    struct kvm_irqchip *chip;
> +
> +    chip = container_of(s, struct kvm_irqchip, chip.ioapic);
> +
> +    return kvm_set_irqchip(chip);
> +}
> +
> +static const VMStateDescription vmstate_kvm_ioapic = {
> +    .name = "ioapic-kvm",
> +    .version_id = 1,
> +    .minimum_version_id = 1,
> +    .post_load = ioapic_post_load,
> +    .pre_save = ioapic_pre_save,
> +    .fields      = (VMStateField []) {
> +        VMSTATE_U64(base_address, struct kvm_ioapic_state),
> +        VMSTATE_UINT32(id, struct kvm_ioapic_state),
> +        VMSTATE_UINT32(ioregsel, struct kvm_ioapic_state),
> +        VMSTATE_UINT32(irr, struct kvm_ioapic_state),
> +        VMSTATE_ARRAY_UNSAFE(redirtbl, struct kvm_ioapic_state, IOAPIC_NUM_PINS, 0, vmstate_info_u64, __u64),
> +        VMSTATE_END_OF_LIST()
> +    }
> +};
> +
> +
> +static void kvm_ioapic_set_irq(void *opaque, int vector, int level)
> +{
> +}
> +
> +qemu_irq *kvm_ioapic_init(void)
> +{
> +    struct kvm_irqchip *s;
> +
> +    s = qemu_mallocz(sizeof(*s));
> +
> +    ioapic_reset(&s->chip.ioapic);
> +
> +    vmstate_register(0, &vmstate_kvm_ioapic, &s->chip.ioapic);
> +    qemu_register_reset(ioapic_reset, &s->chip.ioapic);
> +
> +    return qemu_allocate_irqs(kvm_ioapic_set_irq, &s->chip.ioapic, IOAPIC_NUM_PINS);
> +}
> Index: qemu/hw/pc.h
> ===================================================================
> --- qemu.orig/hw/pc.h
> +++ qemu/hw/pc.h
> @@ -48,6 +48,8 @@ void ioapic_set_irq(void *opaque, int ve
>  void apic_reset_irq_delivered(void);
>  int apic_get_irq_delivered(void);
>
> +qemu_irq *kvm_ioapic_init(void);
> +
>  /* i8254.c */
>
>  #define PIT_FREQ 1193182
> Index: qemu/kvm-all.c
> ===================================================================
> --- qemu.orig/kvm-all.c
> +++ qemu/kvm-all.c
> @@ -411,6 +411,26 @@ int kvm_check_extension(KVMState *s, uns
>     return ret;
>  }
>
> +#ifdef KVM_CAP_IRQCHIP
> +int kvm_set_irqchip(struct kvm_irqchip *chip)
> +{
> +    if (!kvm_state->irqchip_in_kernel) {
> +        return 0;
> +    }
> +
> +    return kvm_vm_ioctl(kvm_state, KVM_SET_IRQCHIP, chip);
> +}
> +
> +int kvm_get_irqchip(struct kvm_irqchip *chip)
> +{
> +    if (!kvm_state->irqchip_in_kernel) {
> +        return 0;
> +    }
> +
> +    return kvm_vm_ioctl(kvm_state, KVM_GET_IRQCHIP, chip);
> +}
> +#endif
> +
>  int kvm_init(int smp_cpus)
>  {
>     static const char upgrade_note[] =
> Index: qemu/kvm.h
> ===================================================================
> --- qemu.orig/kvm.h
> +++ qemu/kvm.h
> @@ -16,6 +16,7 @@
>
>  #include "config.h"
>  #include "qemu-queue.h"
> +#include <linux/kvm.h>
>
>  #ifdef CONFIG_KVM
>  extern int kvm_allowed;
> @@ -63,6 +64,9 @@ int kvm_update_guest_debug(CPUState *env
>  int kvm_pit_in_kernel(void);
>  int kvm_irqchip_in_kernel(void);
>
> +int kvm_set_irqchip(struct kvm_irqchip *chip);
> +int kvm_get_irqchip(struct kvm_irqchip *chip);
> +
>  /* internal API */
>
>  struct KVMState;
>
>



-- 
Glauber  Costa.
"Free as in Freedom"
http://glommer.net

"The less confident you are, the more serious you have to act."