Re: [PATCH v6 05/16] i386/pc_sysfw: Ensure sysfw flash configuration does not conflict with IGVM

["Gupta, Pankaj" <pankaj.gupta@amd.com>]

> When using an IGVM file the configuration of the system firmware is
> defined by IGVM directives contained in the file. In this case the user
> should not configure any pflash devices.
> 
> This commit skips initialization of the ROM mode when pflash0 is not set
> then checks to ensure no pflash devices have been configured when using
> IGVM, exiting with an error message if this is not the case.
> 
> Signed-off-by: Roy Hopkins <roy.hopkins@suse.com>

Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>

> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
> Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
> ---
>   hw/i386/pc_sysfw.c | 31 ++++++++++++++++++++++++++++---
>   1 file changed, 28 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
> index ef80281d28..f5e40b3ef6 100644
> --- a/hw/i386/pc_sysfw.c
> +++ b/hw/i386/pc_sysfw.c
> @@ -219,7 +219,13 @@ void pc_system_firmware_init(PCMachineState *pcms,
>       BlockBackend *pflash_blk[ARRAY_SIZE(pcms->flash)];
>   
>       if (!pcmc->pci_enabled) {
> -        x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, true);
> +        /*
> +         * If an IGVM file is specified then the firmware must be provided
> +         * in the IGVM file.
> +         */
> +        if (!X86_MACHINE(pcms)->igvm) {
> +            x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, true);
> +        }
>           return;
>       }
>   
> @@ -239,8 +245,13 @@ void pc_system_firmware_init(PCMachineState *pcms,
>       }
>   
>       if (!pflash_blk[0]) {
> -        /* Machine property pflash0 not set, use ROM mode */
> -        x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, false);
> +        /*
> +         * Machine property pflash0 not set, use ROM mode unless using IGVM,
> +         * in which case the firmware must be provided by the IGVM file.
> +         */
> +        if (!X86_MACHINE(pcms)->igvm) {
> +            x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, false);
> +        }
>       } else {
>           if (kvm_enabled() && !kvm_readonly_mem_enabled()) {
>               /*
> @@ -256,6 +267,20 @@ void pc_system_firmware_init(PCMachineState *pcms,
>       }
>   
>       pc_system_flash_cleanup_unused(pcms);
> +
> +    /*
> +     * The user should not have specified any pflash devices when using IGVM
> +     * to configure the guest.
> +     */
> +    if (X86_MACHINE(pcms)->igvm) {
> +        for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
> +            if (pcms->flash[i]) {
> +                error_report("pflash devices cannot be configured when "
> +                             "using IGVM");
> +                exit(1);
> +            }
> +        }
> +    }
>   }
>   
>   void x86_firmware_configure(hwaddr gpa, void *ptr, int size)