Re: [Qemu-devel] [PATCH v7 17/26] target/i386: encrypt bios rom

[Dr. David Alan Gilbert]

* Brijesh Singh (address@hidden) wrote:
> SEV requires that guest bios must be encrypted before booting the guest.

I'm curious; is it just the main BIOS that needs encryption - what about
things like device/PXE rom images?

Dave

> 
> Cc: "Michael S. Tsirkin" <address@hidden>
> Cc: Paolo Bonzini <address@hidden>
> Cc: Richard Henderson <address@hidden>
> Cc: Eduardo Habkost <address@hidden>
> Signed-off-by: Brijesh Singh <address@hidden>
> ---
>  hw/i386/pc_sysfw.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
> index 6b183747fcea..8ddbbf74d330 100644
> --- a/hw/i386/pc_sysfw.c
> +++ b/hw/i386/pc_sysfw.c
> @@ -112,6 +112,8 @@ static void pc_system_flash_init(MemoryRegion *rom_memory)
>      pflash_t *system_flash;
>      MemoryRegion *flash_mem;
>      char name[64];
> +    void *flash_ptr;
> +    int ret, flash_size;
>  
>      sector_bits = 12;
>      sector_size = 1 << sector_bits;
> @@ -168,6 +170,17 @@ static void pc_system_flash_init(MemoryRegion 
> *rom_memory)
>          if (unit == 0) {
>              flash_mem = pflash_cfi01_get_memory(system_flash);
>              pc_isa_bios_init(rom_memory, flash_mem, size);
> +
> +            /* Encrypt the pflash boot ROM */
> +            if (kvm_memcrypt_enabled()) {
> +                flash_ptr = memory_region_get_ram_ptr(flash_mem);
> +                flash_size = memory_region_size(flash_mem);
> +                ret = kvm_memcrypt_encrypt_data(flash_ptr, flash_size);
> +                if (ret) {
> +                    error_report("failed to encrypt pflash rom");
> +                    exit(1);
> +                }
> +            }
>          }
>      }
>  }
> -- 
> 2.14.3
> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK