Re: [PATCH 00/19] Workaround Windows failing to find 64bit SMBIOS entry point with SeaBIOS

[Michael S. Tsirkin]

On Tue, Feb 27, 2024 at 04:47:30PM +0100, Igor Mammedov wrote:
> Windows (10) bootloader when running on top of SeaBIOS, fails to find         
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> SMBIOSv3 entry point. Tracing it shows that it looks for v2 anchor markers    
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> only and not v3. Tricking it into believing that entry point is found         
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> lets Windows successfully locate and parse SMBIOSv3 tables. Whether it        
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> will be fixed on Windows side is not clear so here goes a workaround.         
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>                                                                               
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> Idea is to try build v2 tables if QEMU configuration permits,                 
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> and fallback to v3 tables otherwise. That will mask Windows issue             
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> form majority of users.                                                       
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> However if VM configuration can't be described (typically large VMs)          
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> by v2 tables, QEMU will use SMBIOSv3 and Windows will hit the issue           
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> again. In this case complain to Microsoft and/or use UEFI instead of          
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> SeaBIOS (requires reinstall).                                                 
>    

Sounds like the best we can do.

> Default compat setting of smbios-entry-point-type after series                
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> for pc/q35 machines:                                                          
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>   * 9.0-newer: 'auto'                                                         
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>   * 8.1-8.2: '64'                                                             
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>   * 8.0-older: '32'                                                           
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>                                                                               
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> Fixes: https://gitlab.com/qemu-project/qemu/-/issues/2008                     
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> CC: peter.maydell@linaro.org                                                  
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> CC: pbonzini@redhat.com                                                       
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> CC: mst@redhat.com                                                            
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> CC: gaosong@loongson.cn                                                       
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> CC: alistair.francis@wdc.com                                                  
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> CC: palmer@dabbelt.com                                                        
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> CC: bin.meng@windriver.com                                                    
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> CC: liwei1518@gmail.com                                                       
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> CC: dbarboza@ventanamicro.com                                                 
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> CC: zhiwei_liu@linux.alibaba.com                                              
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> CC: imammedo@redhat.com                                                       
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> CC: anisinha@redhat.com                                                       
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> CC: philmd@linaro.org                                                         
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> CC: wangyanan55@huawei.com                                                    
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> CC: eblake@redhat.com                                                         
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> CC: armbru@redhat.com                                                         
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> CC: qemu-arm@nongnu.org                                                       
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> CC: qemu-riscv@nongnu.org                                                     
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> CC: f.ebner@proxmox.com                                                       
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>                           
> Igor Mammedov (19):
>   tests: smbios: make it possible to write SMBIOS only test
>   tests: smbios: add test for -smbios type=11 option
>   tests: smbios: add test for legacy mode CLI options
>   smbios: cleanup smbios_get_tables() from legacy handling
>   smbios: get rid of smbios_smp_sockets global
>   smbios: get rid of smbios_legacy global
>   smbios: avoid mangling user provided tables
>   smbios: don't check type4 structures in legacy mode
>   smbios: build legacy mode code only for 'pc' machine
>   smbios: handle errors consistently
>   smbios: clear smbios_tables pointer after freeing
>   get rid of global smbios_ep_type
>   smbios: extend smbios-entry-point-type with 'auto' value
>   smbios: in case of entry point is 'auto' try to build v2 tables 1st
>   smbios: error out when building type 4 table is not possible
>   smbios: clear smbios_type4_count before building tables
>   tests: acpi/smbios: whitelist expected blobs
>   pc/q35: set SMBIOS entry point type to 'auto' by default
>   tests: acpi: update expected SSDT.dimmpxm blob
> 
>  hw/i386/fw_cfg.h                     |   3 +-
>  include/hw/firmware/smbios.h         |  29 +-
>  hw/arm/virt.c                        |   6 +-
>  hw/i386/Kconfig                      |   1 +
>  hw/i386/fw_cfg.c                     |  14 +-
>  hw/i386/pc.c                         |   4 +-
>  hw/i386/pc_piix.c                    |   4 +
>  hw/i386/pc_q35.c                     |   3 +
>  hw/loongarch/virt.c                  |   7 +-
>  hw/riscv/virt.c                      |   6 +-
>  hw/smbios/Kconfig                    |   2 +
>  hw/smbios/meson.build                |   4 +
>  hw/smbios/smbios.c                   | 481 +++++++++++----------------
>  hw/smbios/smbios_legacy.c            | 185 +++++++++++
>  hw/smbios/smbios_legacy_stub.c       |  16 +
>  qapi/machine.json                    |   5 +-
>  tests/data/acpi/q35/SSDT.dimmpxm     | Bin 1815 -> 1815 bytes
>  tests/data/smbios/type11_blob        | Bin 0 -> 11 bytes
>  tests/data/smbios/type11_blob.legacy | Bin 0 -> 10 bytes
>  tests/qtest/bios-tables-test.c       |  81 ++++-
>  20 files changed, 535 insertions(+), 316 deletions(-)
>  create mode 100644 hw/smbios/smbios_legacy.c
>  create mode 100644 hw/smbios/smbios_legacy_stub.c
>  create mode 100644 tests/data/smbios/type11_blob
>  create mode 100644 tests/data/smbios/type11_blob.legacy
> 
> -- 
> 2.39.3