[Xen-devel] [PATCH 3/8] kexec: add public interface for improved load/unload sub-ops

[Jan Beulich]

>>> On 08.04.13 at 20:59, David Vrabel <david.vrabel at citrix.com> wrote:
> @@ -152,6 +152,63 @@ typedef struct xen_kexec_range {
>      unsigned long start;
>  } xen_kexec_range_t;
>  
> +#if __XEN_INTERFACE_VERSION__ >= 0x00040300
> +/*
> + * A contiguous chunk of a kexec image and it's destination machine
> + * address.
> + */
> +typedef struct xen_kexec_segment {
> +    XEN_GUEST_HANDLE_64(const_void) buf;
> +    uint64_t buf_size;
> +    uint64_t dest_maddr;
> +    uint64_t dest_size;

So you made uint64_aligned_t available in the previous patch,
but now you don't use it?

> +} xen_kexec_segment_t;
> +DEFINE_XEN_GUEST_HANDLE(xen_kexec_segment_t);
> +
> +/*
> + * Load a kexec image into memory.
> + *
> + * For KEXEC_TYPE_DEFAULT images, the segments may be anywhere in RAM.
> + * The image is relocated prior to being executed.
> + *
> + * For KEXEC_TYPE_CRASH images, each segment of the image must reside
> + * in the memory region reserved for kexec (KEXEC_RANGE_MA_CRASH) and
> + * the entry point must be within the image. The caller is responsible
> + * for ensuring that multiple images do not overlap.
> + */
> +
> +#define KEXEC_CMD_kexec_load 4
> +typedef struct xen_kexec_load {
> +    uint8_t  type;        /* One of KEXEC_TYPE_* */

Explicit padding please.

> +    uint16_t arch;        /* ELF machine type (EM_*). */
> +    uint32_t nr_segments;
> +    XEN_GUEST_HANDLE_64(xen_kexec_segment_t) segments;
> +    uint64_t entry_maddr; /* image entry point machine address. */
> +} xen_kexec_load_t;
> +DEFINE_XEN_GUEST_HANDLE(xen_kexec_load_t);
> +
> +/*
> + * Unload a kexec image.
> + *
> + * Type must be one of KEXEC_TYPE_DEFAULT or KEXEC_TYPE_CRASH.
> + */
> +#define KEXEC_CMD_kexec_unload 5
> +typedef struct xen_kexec_unload {
> +    uint8_t type;
> +} xen_kexec_unload_t;
> +DEFINE_XEN_GUEST_HANDLE(xen_kexec_unload_t);
> +
> +#else /* __XEN_INTERFACE_VERSION__ < 0x00040300 */
> +
> +#define KEXEC_CMD_kexec_load KEXEC_CMD_kexec_load_v1
> +#define KEXEC_CMD_kexec_unload KEXEC_CMD_kexec_unload_v1
> +typedef struct xen_kexec_load {
> +    int type;
> +    xen_kexec_image_t image;
> +} xen_kexec_load_t;

I don't really like this duplication, but I admit that the alternatives
I can think of aren't much better either.

Jan