Re: [Xen-devel] [RFC PATCH V3 2/2] qemu: support xen hvm direct kernel boot

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Fri, 20 Jun 2014, Chunyan Liu wrote:
> qemu side patch to support xen HVM direct kernel boot:
> if -kernel exists, calls xen_load_linux(), which will read kernel/initrd
> and add a linuxboot.bin or multiboot.bin option rom. The
> linuxboot.bin/multiboot.bin will load kernel/initrd and jump to execute
> kernel directly. It's working when xen uses seabios.
> 
> Signed-off-by: Chunyan Liu <cyliu@xxxxxxxx>
> ---
>  hw/i386/pc.c           | 22 ++++++++++++++++++++++
>  hw/i386/pc_piix.c      |  7 +++++++
>  hw/i386/xen/xen_apic.c |  1 +
>  include/hw/i386/pc.h   |  5 +++++
>  4 files changed, 35 insertions(+)
> 
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index 3e0ecf1..e005136 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -1183,6 +1183,28 @@ void pc_acpi_init(const char *default_dsdt)
>      }
>  }
>  
> +FWCfgState *xen_load_linux(const char *kernel_filename,
> +                           const char *kernel_cmdline,
> +                           const char *initrd_filename,
> +                           ram_addr_t below_4g_mem_size,
> +                           PcGuestInfo *guest_info)
> +{
> +    int i;
> +    FWCfgState *fw_cfg;
> +
> +    assert(kernel_filename != NULL);
> +
> +    fw_cfg = fw_cfg_init(BIOS_CFG_IOPORT, BIOS_CFG_IOPORT + 1, 0, 0);

Is it actually OK to initialize just BIOS_CFG_IOPORT and avoid
everything else currently done in bochs_bios_init?
Would it make sense to simply call bochs_bios_init?


> +    rom_set_fw(fw_cfg);
> +
> +    load_linux(fw_cfg, kernel_filename, initrd_filename, kernel_cmdline, 
> below_4g_mem_size);
> +    for (i = 0; i < nb_option_roms; i++) {
> +        rom_add_option(option_rom[i].name, option_rom[i].bootindex);
> +    }

Wouldn't this have the unintended consequence of possibly loading other
option_roms into the guest memory?


> +    guest_info->fw_cfg = fw_cfg;
> +    return fw_cfg;
> +}
> +
>  FWCfgState *pc_memory_init(MemoryRegion *system_memory,
>                             const char *kernel_filename,
>                             const char *kernel_cmdline,
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index a48e263..b737868 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -158,6 +158,13 @@ static void pc_init1(MachineState *machine,
>                         machine->initrd_filename,
>                         below_4g_mem_size, above_4g_mem_size,
>                         rom_memory, &ram_memory, guest_info);
> +    } else if (machine->kernel_filename != NULL) {
> +        /* For xen HVM direct kernel boot, load linux here */
> +        fw_cfg = xen_load_linux(machine->kernel_filename,
> +                                machine->kernel_cmdline,
> +                                machine->initrd_filename,
> +                                below_4g_mem_size,
> +                                guest_info);
>      }
>  
>      gsi_state = g_malloc0(sizeof(*gsi_state));
> diff --git a/hw/i386/xen/xen_apic.c b/hw/i386/xen/xen_apic.c
> index 63bb7f7..f5acd6a 100644
> --- a/hw/i386/xen/xen_apic.c
> +++ b/hw/i386/xen/xen_apic.c
> @@ -40,6 +40,7 @@ static void xen_apic_realize(DeviceState *dev, Error **errp)
>  {
>      APICCommonState *s = APIC_COMMON(dev);
>  
> +    s->vapic_control = 0;
>      memory_region_init_io(&s->io_memory, OBJECT(s), &xen_apic_io_ops, s,
>                            "xen-apic-msi", APIC_SPACE_SIZE);

Why this change? It is not mentioned in the commit message.


> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> index ca7a0bd..171a597 100644
> --- a/include/hw/i386/pc.h
> +++ b/include/hw/i386/pc.h
> @@ -134,6 +134,11 @@ PcGuestInfo *pc_guest_info_init(ram_addr_t 
> below_4g_mem_size,
>  void pc_pci_as_mapping_init(Object *owner, MemoryRegion *system_memory,
>                              MemoryRegion *pci_address_space);
>  
> +FWCfgState *xen_load_linux(const char *kernel_filename,
> +                           const char *kernel_cmdline,
> +                           const char *initrd_filename,
> +                           ram_addr_t below_4g_mem_size,
> +                           PcGuestInfo *guest_info);
>  FWCfgState *pc_memory_init(MemoryRegion *system_memory,
>                             const char *kernel_filename,
>                             const char *kernel_cmdline,
> -- 
> 1.8.4.5
> 

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