Re: [Xen-devel] [PATCH v3 11/16] hvmloader: Load OVMF from modules

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 25.02.16 at 15:56, <anthony.perard@xxxxxxxxxx> wrote:
> --- a/tools/firmware/hvmloader/ovmf.c
> +++ b/tools/firmware/hvmloader/ovmf.c
> @@ -34,17 +34,10 @@
>  #include <xen/hvm/ioreq.h>
>  #include <xen/memory.h>
>  
> -#define ROM_INCLUDE_OVMF
> -#include "roms.inc"
> -
> -#define OVMF_SIZE               (sizeof(ovmf))
>  #define OVMF_MAXOFFSET          0x000FFFFFULL
> -#define OVMF_BEGIN              (0x100000000ULL - ((OVMF_SIZE + 
> OVMF_MAXOFFSET) & ~OVMF_MAXOFFSET))
> -#define OVMF_END                (OVMF_BEGIN + OVMF_SIZE)
>  #define LOWCHUNK_BEGIN          0x000F0000
>  #define LOWCHUNK_SIZE           0x00010000
>  #define LOWCHUNK_MAXOFFSET      0x0000FFFF
> -#define LOWCHUNK_END            (OVMF_BEGIN + OVMF_SIZE)
>  #define OVMF_INFO_PHYSICAL_ADDRESS 0x00001000
>  
>  extern unsigned char dsdt_anycpu_qemu_xen[];
> @@ -97,16 +90,20 @@ static void ovmf_load(const struct bios_config *config,
>                        void *bios_addr, uint32_t bios_length)
>  {
>      xen_pfn_t mfn;
> -    uint64_t addr = OVMF_BEGIN;
> +    uint64_t addr = 0x100000000ULL
> +        - ((bios_length + OVMF_MAXOFFSET) & ~OVMF_MAXOFFSET);
> +    uint64_t ovmf_end = addr + bios_length;
> +
> +    ovmf_config.bios_address = addr;
> +    ovmf_config.image_size = bios_length;
>  
>      /* Copy low-reset vector portion. */
> -    memcpy((void *) LOWCHUNK_BEGIN, (uint8_t *) config->image
> -           + OVMF_SIZE
> -           - LOWCHUNK_SIZE,
> +    memcpy((void *) LOWCHUNK_BEGIN,
> +           (uint8_t *) bios_addr + bios_length - LOWCHUNK_SIZE,
>             LOWCHUNK_SIZE);
>  
>      /* Ensure we have backing page prior to moving FD. */
> -    while ( (addr >> PAGE_SHIFT) != (OVMF_END >> PAGE_SHIFT) )
> +    while ( (addr >> PAGE_SHIFT) != (ovmf_end >> PAGE_SHIFT) )
>      {
>          mfn = (uint32_t) (addr >> PAGE_SHIFT);
>          addr += PAGE_SIZE;
> @@ -114,7 +111,7 @@ static void ovmf_load(const struct bios_config *config,
>      }
>  
>      /* Copy FD. */
> -    memcpy((void *) OVMF_BEGIN, config->image, OVMF_SIZE);
> +    memcpy((void *) ovmf_config.bios_address, bios_addr, bios_length);
>  }

Is this safe, considering that source and destination may now
overlap? Thinking about it, the same consideration applies to
BIOS placement below 1Mb too. Roger - should we perhaps
amend the respective hvm_start_info comment to exclude
anything getting placed below 1Mb?

Jan


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