Re: [PATCH 6/9] i386/pc: Skip initialization of system FW when using IGVM

[Daniel P . Berrangé]

On Tue, Feb 27, 2024 at 02:50:12PM +0000, Roy Hopkins wrote:
> When using an IGVM file the configuration of the system firmware is
> defined by IGVM directives contained in the file. Therefore the default
> system firmware should not be initialized when an IGVM file has been
> provided.
> 
> This commit checks to see if an IGVM file has been provided and, if it
> has then the standard system firmware initialization is skipped and any
> prepared flash devices are cleaned up.
> 
> Signed-off-by: Roy Hopkins <roy.hopkins@suse.com>
> ---
>  hw/i386/pc.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index f8eb684a49..17bb211708 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -63,6 +63,7 @@
>  #include "e820_memory_layout.h"
>  #include "trace.h"
>  #include CONFIG_DEVICES
> +#include "exec/confidential-guest-support.h"
>  
>  #ifdef CONFIG_XEN_EMU
>  #include "hw/xen/xen-legacy-backend.h"
> @@ -1023,8 +1024,15 @@ void pc_memory_init(PCMachineState *pcms,
>          }
>      }
>  
> -    /* Initialize PC system firmware */
> -    pc_system_firmware_init(pcms, rom_memory);
> +    /*
> +     * If this is a confidential guest configured using IGVM then the IGVM
> +     * configuration will include the system firmware. In this case do not
> +     * initialise PC system firmware.
> +     */
> +    if (!cgs_is_igvm(machine->cgs)) {
> +        /* Initialize PC system firmware */
> +        pc_system_firmware_init(pcms, rom_memory);
> +    }

If the user has given explicit pflash config I think we should be
reporting an error for the invalid configuration, rather than
silently ignoring their mistake.

>  
>      option_rom_mr = g_malloc(sizeof(*option_rom_mr));
>      memory_region_init_ram(option_rom_mr, NULL, "pc.rom", PC_ROM_SIZE,
> -- 
> 2.43.0
> 
> 

With regards,
Daniel
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