Re: [PATCH 2/2] x86/pvh: extract only 4 bytes of start address for 32 bit kernels

[Stefano Garzarella]

On Tue, Mar 02, 2021 at 09:03:15AM +0000, David Edmondson wrote:
> When loading the PVH start address from a 32 bit ELF note, extract
> only the appropriate number of bytes.
>
> Fixes: ab969087da65 ("pvh: Boot uncompressed kernel using direct boot ABI")
> Signed-off-by: David Edmondson <david.edmondson@oracle.com>
> ---
> hw/i386/x86.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/hw/i386/x86.c b/hw/i386/x86.c
> index 6329f90ef9..7865660e2c 100644
> --- a/hw/i386/x86.c
> +++ b/hw/i386/x86.c
> @@ -690,6 +690,8 @@ static uint64_t read_pvh_start_addr(void *arg1, void *arg2, 
> bool is64)
>         elf_note_data_addr =
>             ((void *)nhdr64) + nhdr_size64 +
>             QEMU_ALIGN_UP(nhdr_namesz, phdr_align);
> +
> +        pvh_start_addr = *elf_note_data_addr;
>     } else {
>         struct elf32_note *nhdr32 = (struct elf32_note *)arg1;
>         uint32_t nhdr_size32 = sizeof(struct elf32_note);
> @@ -699,9 +701,9 @@ static uint64_t read_pvh_start_addr(void *arg1, void *arg2, 
> bool is64)
>         elf_note_data_addr =
>             ((void *)nhdr32) + nhdr_size32 +
>             QEMU_ALIGN_UP(nhdr_namesz, phdr_align);
> -    }
>
> -    pvh_start_addr = *elf_note_data_addr;
> +        pvh_start_addr = *(uint32_t *)elf_note_data_addr;
> +    }
>
>     return pvh_start_addr;
> }
> --
> 2.30.0

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>