On 25/09/2018 17:20, Thomas Huth wrote:
> The IplParameterBlock and QemuIplParameters structures are declared
> with QEMU_PACKED, so the compiler assumes that the structures do not
> need to be aligned in memory. Since the are listed after a "bool"
> within the S390IPLState, the IplParameterBlock and QemuIplParameters
> are also indeed mis-aligned in memory. This causes problems on Sparc
> during migration, since we use VMSTATE_UINT16 in vmstate_iplb to access
> the devno member for example, and the corresponding migration functions
> (like qemu_get_be16s) then try to access a 16-bit value from a mis-
> aligned memory address.
> The easiest solution to fix this problem is to move the packed structures
> to the beginning of the S390IPLState. Also add some additional comments
> here to prevent that this problem will be introduced again in the future.
>
> Signed-off-by: Thomas Huth <th...@redhat.com>
> ---
> hw/s390x/ipl.h | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/hw/s390x/ipl.h b/hw/s390x/ipl.h
> index 4e87b89..f72a82f 100644
> --- a/hw/s390x/ipl.h
> +++ b/hw/s390x/ipl.h
> @@ -132,15 +132,17 @@ typedef struct QemuIplParameters QemuIplParameters;
> struct S390IPLState {
> /*< private >*/
> DeviceState parent_obj;
> + /* Packed structs first (to make sure we've got a proper alignment): */
Is that a sad smiley at the end? ;)
> + IplParameterBlock iplb;
> + QemuIplParameters qipl;
> + /* Other private members without packed attribute: */
> uint64_t start_addr;
> uint64_t compat_start_addr;
> uint64_t bios_start_addr;
> uint64_t compat_bios_start_addr;
> bool enforce_bios;
> - IplParameterBlock iplb;
> bool iplb_valid;
> bool netboot;
> - QemuIplParameters qipl;
> /* reset related properties don't have to be migrated or reset */
> enum s390_reset reset_type;
> int reset_cpu_index;
>
Instead of the comment, compile time asserts using offsetof?
Anyhow
Reviewed-by: David Hildenbrand <da...@redhat.com>
--
Thanks,
David / dhildenb
