Re: [Qemu-devel] [PATCH v2] pc: acpi-build: make linker & RSDP tables dynamic

[Igor Mammedov]

On Thu, 11 Dec 2014 12:37:10 +0200
"Michael S. Tsirkin" <address@hidden> wrote:

> On Thu, Dec 11, 2014 at 09:10:53AM +0000, Igor Mammedov wrote:
> > linker and RSDP tables are build only once, so if later
> 
> s/build/built/
> 
> > during rebuild sizes of other ACPI tables change
> > pointers will be patched incorrectly due to wrong
> > offsets.
> > 
> > To fix it rebuild linker and RSDP tables along with
> > the rest of ACPI tables so that they would have correct
> > offsets.
> 
> Actually, I understand the argument about the
> linker, but do you really believe RSDP will ever change?
it changes since RSDT is at the end and its offset changes
every time a below table changes its size.

If RSDT were at the start then it might be
possible to keep RSDP immutable.

I'll check if it's feasible.

This fix however is more robust and doesn't care about
to table order, the best would be to combine ordering
fix for old machines for stable and this patch for 
new machines since 2.3.

> 
> How about we split out RSDP and linker changes?
> 
> Also s/imutable/immutable/ in a bunch of places below.
Thanks, I'll fix this one.

> 
> > Here is a simple reproducer:
> >  1: hotplug bridge using command:
> >      device_add pci-bridge,chassis_nr=1
> >  2: reset system from monitor:
> >      system_reset
> > 
> > As result pointers to ACPI tables are not correct
> > and guest can't read/parse ACPI tables.
> > 
> > Windows guests just refuse to boot and
> > Linux guests are more resilient and try to boot without
> > ACPI, sometimes successfully.
> > 
> > keep brokenness in 2.1 and older machine types for
> > the sake of migration. 2.2.0 can't be helped but we
> > can fix it with 2.2.1
> 
> 
> Why do you say this?
> It can be helped by patch that I sent, skipping
> hotplugged bridges, no?
> 
> 
> > Signed-off-by: Igor Mammedov <address@hidden>
> > ---
> > v2:
> >   move compat fix to 2.1 machine type,
> >    suggsted by: "Michael S. Tsirkin" <address@hidden>
> > ---
> >  hw/i386/acpi-build.c | 30 +++++++++++++++++++++++-------
> >  hw/i386/pc_piix.c    |  3 +++
> >  hw/i386/pc_q35.c     |  3 +++
> >  include/hw/i386/pc.h |  1 +
> >  4 files changed, 30 insertions(+), 7 deletions(-)
> > 
> > diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> > index b37a397..4d2452d 100644
> > --- a/hw/i386/acpi-build.c
> > +++ b/hw/i386/acpi-build.c
> > @@ -1509,6 +1509,10 @@ struct AcpiBuildState {
> >      /* Copy of table in RAM (for patching). */
> >      ram_addr_t table_ram;
> >      uint32_t table_size;
> > +    ram_addr_t linker_ram;
> > +    uint32_t linker_size;
> > +    ram_addr_t rsdp_ram;
> > +    uint32_t rsdp_size;
> >      /* Is table patched? */
> >      uint8_t patched;
> >      PcGuestInfo *guest_info;
> > @@ -1714,6 +1718,10 @@ static void acpi_build_update(void *build_opaque, 
> > uint32_t offset)
> >      assert(acpi_data_len(tables.table_data) == build_state->table_size);
> >      memcpy(qemu_get_ram_ptr(build_state->table_ram), 
> > tables.table_data->data,
> >             build_state->table_size);
> > +    memcpy(qemu_get_ram_ptr(build_state->linker_ram), tables.linker->data,
> > +           build_state->linker_size);
> > +    memcpy(qemu_get_ram_ptr(build_state->rsdp_ram), tables.rsdp->data,
> > +           build_state->rsdp_size);
> >  
> >      cpu_physical_memory_set_dirty_range_nocode(build_state->table_ram,
> >                                                 build_state->table_size);
> > @@ -1779,17 +1787,25 @@ void acpi_setup(PcGuestInfo *guest_info)
> >      assert(build_state->table_ram != RAM_ADDR_MAX);
> >      build_state->table_size = acpi_data_len(tables.table_data);
> >  
> > -    acpi_add_rom_blob(NULL, tables.linker, "etc/table-loader");
> > +    build_state->linker_ram = acpi_add_rom_blob(build_state, tables.linker,
> > +                                                "etc/table-loader");
> > +    build_state->linker_size = acpi_data_len(tables.linker);
> >  
> >      fw_cfg_add_file(guest_info->fw_cfg, ACPI_BUILD_TPMLOG_FILE,
> >                      tables.tcpalog->data, acpi_data_len(tables.tcpalog));
> >  
> > -    /*
> > -     * RSDP is small so it's easy to keep it immutable, no need to
> > -     * bother with ROM blobs.
> > -     */
> > -    fw_cfg_add_file(guest_info->fw_cfg, ACPI_BUILD_RSDP_FILE,
> > -                    tables.rsdp->data, acpi_data_len(tables.rsdp));
> > +    if (guest_info->has_imutable_rsdp) {
> > +        /*
> > +         * RSDP is small so it's easy to keep it immutable, no need to
> > +         * bother with ROM blobs.
> > +         */
> > +        fw_cfg_add_file(guest_info->fw_cfg, ACPI_BUILD_RSDP_FILE,
> > +                        tables.rsdp->data, acpi_data_len(tables.rsdp));
> > +    } else {
> > +        build_state->rsdp_ram = acpi_add_rom_blob(build_state, tables.rsdp,
> > +                                                  ACPI_BUILD_RSDP_FILE);
> > +        build_state->rsdp_size = acpi_data_len(tables.rsdp);
> > +    }
> >  
> >      qemu_register_reset(acpi_build_reset, build_state);
> >      acpi_build_reset(build_state);
> > diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> > index 685fa54..61170de 100644
> > --- a/hw/i386/pc_piix.c
> > +++ b/hw/i386/pc_piix.c
> > @@ -60,6 +60,7 @@ static const int ide_iobase2[MAX_IDE_BUS] = { 0x3f6, 
> > 0x376 };
> >  static const int ide_irq[MAX_IDE_BUS] = { 14, 15 };
> >  
> >  static bool has_acpi_build = true;
> > +static bool has_imutable_rsdp;
> 
> s/imutable/immutable/
> 
> >  static int legacy_acpi_table_size;
> >  static bool smbios_defaults = true;
> >  static bool smbios_legacy_mode;
> > @@ -168,6 +169,7 @@ static void pc_init1(MachineState *machine,
> >  
> >      guest_info->isapc_ram_fw = !pci_enabled;
> >      guest_info->has_reserved_memory = has_reserved_memory;
> > +    guest_info->has_imutable_rsdp = has_imutable_rsdp;
> >  
> >      if (smbios_defaults) {
> >          MachineClass *mc = MACHINE_GET_CLASS(machine);
> > @@ -323,6 +325,7 @@ static void pc_compat_2_1(MachineState *machine)
> >      x86_cpu_compat_set_features("core2duo", FEAT_1_ECX, CPUID_EXT_VMX, 0);
> >      x86_cpu_compat_kvm_no_autodisable(FEAT_8000_0001_ECX, CPUID_EXT3_SVM);
> >      pcms->enforce_aligned_dimm = false;
> > +    has_imutable_rsdp = true;
> >  }
> >  
> >  static void pc_compat_2_0(MachineState *machine)
> > diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> > index 121f620..0f071a9 100644
> > --- a/hw/i386/pc_q35.c
> > +++ b/hw/i386/pc_q35.c
> > @@ -50,6 +50,7 @@
> >  #define MAX_SATA_PORTS     6
> >  
> >  static bool has_acpi_build = true;
> > +static bool has_imutable_rsdp;
> >  static bool smbios_defaults = true;
> >  static bool smbios_legacy_mode;
> >  static bool smbios_uuid_encoded = true;
> > @@ -154,6 +155,7 @@ static void pc_q35_init(MachineState *machine)
> >      guest_info->isapc_ram_fw = false;
> >      guest_info->has_acpi_build = has_acpi_build;
> >      guest_info->has_reserved_memory = has_reserved_memory;
> > +    guest_info->has_imutable_rsdp = has_imutable_rsdp;
> >  
> >      /* Migration was not supported in 2.0 for Q35, so do not bother
> >       * with this hack (see hw/i386/acpi-build.c).
> > @@ -302,6 +304,7 @@ static void pc_compat_2_1(MachineState *machine)
> >      x86_cpu_compat_set_features("coreduo", FEAT_1_ECX, CPUID_EXT_VMX, 0);
> >      x86_cpu_compat_set_features("core2duo", FEAT_1_ECX, CPUID_EXT_VMX, 0);
> >      x86_cpu_compat_kvm_no_autodisable(FEAT_8000_0001_ECX, CPUID_EXT3_SVM);
> > +    has_imutable_rsdp = true;
> >  }
> >  
> >  static void pc_compat_2_0(MachineState *machine)
> > diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> > index 69d9cf8..acc95ea 100644
> > --- a/include/hw/i386/pc.h
> > +++ b/include/hw/i386/pc.h
> > @@ -104,6 +104,7 @@ struct PcGuestInfo {
> >      int legacy_acpi_table_size;
> >      bool has_acpi_build;
> >      bool has_reserved_memory;
> > +    bool has_imutable_rsdp;
> >  };
> >  
> >  /* parallel.c */
> > -- 
> > 1.8.3.1