Re: [RFC PATCH 2/2] qemu: support xen hvm direct kernel boot

[Paolo Bonzini <pbonzini@redhat.com>]

Il 29/05/2014 05:23, Chunyan Liu ha scritto:
> [support xen HVM direct kernel boot]
> qemu side patch: 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@suse.com>
> ---
>  hw/i386/pc.c         | 29 +++++++++++++++++++++++++++++
>  hw/i386/pc_piix.c    |  7 +++++++
>  include/hw/i386/pc.h |  5 +++++
>  3 files changed, 41 insertions(+)
> 
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index e6369d5..dcd5d48 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -1187,6 +1187,35 @@ 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);
> +    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++) {
> +        /* For xen, we only want to add the linuxboot.bin/multiboot.bin option rom.
> +         * But in option_rom, there is still kvmvapic.bin. We don't want to add it.
> +         */
> +        if (strcmp(option_rom[i].name, "linuxboot.bin") &&
> +            strcmp(option_rom[i].name, "multiboot.bin")) {
> +            continue;
> +        }
> +        rom_add_option(option_rom[i].name, option_rom[i].bootindex);
> +    }

Instead of this hack, you can use:

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);
 

> +    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 eaf3e61..14d4164 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -157,6 +157,13 @@ static void pc_init1(QEMUMachineInitArgs *args,
>                         args->initrd_filename,
>                         below_4g_mem_size, above_4g_mem_size,
>                         rom_memory, &ram_memory, guest_info);
> +    } else if (args->kernel_filename != NULL) {
> +        /* For xen HVM direct kernel boot, load linux here */
> +        fw_cfg = xen_load_linux(args->kernel_filename,
> +                                args->kernel_cmdline,
> +                                args->initrd_filename,
> +                                below_4g_mem_size,
> +                                guest_info);
>      }
>  
>      gsi_state = g_malloc0(sizeof(*gsi_state));
> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> index 32a7687..e472184 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,
>