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Re: [Qemu-devel] [Xen-devel] [RFC PATCH V3 2/2] qemu: support xen hvm di
From: |
Chun Yan Liu |
Subject: |
Re: [Qemu-devel] [Xen-devel] [RFC PATCH V3 2/2] qemu: support xen hvm direct kernel boot |
Date: |
Mon, 23 Jun 2014 20:27:21 -0600 |
>>> On 6/23/2014 at 06:14 PM, in message
<address@hidden>, Stefano
Stabellini <address@hidden> wrote:
> On Sun, 22 Jun 2014, Chun Yan Liu wrote:
> > >>> On 6/20/2014 at 08:08 PM, in message
> > <address@hidden>, Stefano
> > Stabellini <address@hidden> wrote:
> > > 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 <address@hidden>
> > > > ---
> > > > 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?
> >
> > For xen, no.
> >
> > Before this patch, indeed there is another option_rom "kvmvapic" in the
> list,
> > but since the option_rom list is never loaded in xen case, that won't harm.
> >
> But
> > as expected, I think in xen case, it should not be in option_rom list at
> all, since
> > we won't expect to load it. In v1, I tried to check the option_rom name to
> > bypass it and load multiboot.bin/linuxboot.bin only.
> >
> > In comments, Paolo Bonzini suggests a better way, that is to add following
> line
> > in xen_apic_realize():
> > + s->vapic_control = 0;
> > In this way, "kvmvapic" won't be added to the option_rom list. I think that
> > should be the normal way for xen.
> >
> > So, since V2, I updated in this way.
> > http://lists.gnu.org/archive/html/qemu-devel/2014-06/msg00704.html
>
> I see. Paolo's suggestion is a good one.
>
> I would add an assert here to ensure that there is only one option
> rom named "linuxboot.bin", so that we can easily spot if something in
> the future breaks our assumptions.
Yes, that's better. Will update. Thanks!
>
>
> > >
> > >
> > > > + 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
> > > >
> > >
> > > _______________________________________________
> > > Xen-devel mailing list
> > > address@hidden
> > > http://lists.xen.org/xen-devel
> > >
> > >
> >
>
>