On Thu, Feb 21, 2013 at 05:48:11PM +0000, David Vrabel wrote:
> From: David Vrabel <david.vrabel at citrix.com>
>
> In the existing kexec hypercall, the load and unload ops depend on
> internals of the Linux kernel (the page list and code page provided by
> the kernel). The code page is used to transition between Xen context
> and the image so using kernel code doesn't make sense and will not
> work for PVH guests.
>
> Add replacement KEXEC_CMD_kexec_load and KEXEC_CMD_kexec_unload ops
> that no longer require a code page to be provided by the guest -- Xen
> now provides the code for calling the image directly.
>
> The new load op looks similar to the Linux kexec_load system call and
> allows the guest to provide the image data to be loaded. The guest
> specifies the architecture of the image which may be a 32-bit subarch
> of the hypervisor's architecture (i.e., an EM_386 image on an
> EM_X86_64 hypervisor).
>
> The toolstack can now load images without kernel involvement. This is
> required for supporting kexec when using a dom0 with an upstream
> kernel.
>
> Crash images are copied directly into the crash region on load.
> Default images are copied into Xen heap pages and a list of source and
> destination machine addresses is created. This is list is used in
> kexec_reloc() to relocate the image to its destination.
>
> The old load and unload sub-ops are still available (as
> KEXEC_CMD_load_v1 and KEXEC_CMD_unload_v1) and are implemented on top
> of the new infrastructure.
>
> Signed-off-by: David Vrabel <david.vrabel at citrix.com>
[...]
> diff --git a/xen/common/kexec.c b/xen/common/kexec.c
[...]
> -static int kexec_load_unload_compat(unsigned long op,
> - XEN_GUEST_HANDLE_PARAM(void) uarg)
> +static int kexec_load_v1_compat(XEN_GUEST_HANDLE_PARAM(void) uarg)
> {
> #ifdef CONFIG_COMPAT
> compat_kexec_load_v1_t compat_load;
> @@ -807,49 +990,113 @@ static int kexec_load_unload_compat(unsigned long op,
> load.type = compat_load.type;
> XLAT_kexec_image(&load.image, &compat_load.image);
>
> - return kexec_load_unload_internal(op, &load);
> -#else /* CONFIG_COMPAT */
> + return kexec_do_load_v1(&load);
> +#else
> return 0;
-ENOSYS?
> -#endif /* CONFIG_COMPAT */
> +#endif
> }
[...]
> +static int kexec_unload_v1_compat(XEN_GUEST_HANDLE_PARAM(void) uarg)
> +{
> +#ifdef CONFIG_COMPAT
> + compat_kexec_load_v1_t compat_load;
> + xen_kexec_unload_t unload;
> +
> + if ( copy_from_guest(&compat_load, uarg, 1) )
> + return -EFAULT;
> +
> + unload.type = compat_load.type;
> + return kexec_do_unload(&unload);
> +#else
> + return 0;
-ENOSYS?
> +#endif
> +}
...and in other similar places...
Daniel
