[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [PATCH 4/4] kexec/xen: directly load images images into Xen



On Wed, Nov 06, 2013 at 02:55:22PM +0000, David Vrabel wrote:
> From: David Vrabel <david.vrabel@xxxxxxxxxx>
> 
> Xen 4.4 has an improvided kexec hypercall ABI that allows images to be
> loaded and executed without any kernel involvement.  Use the API
> provided by libxc to load images when running in a Xen guest.
> 
> Support for loading images via the kexec_load syscall in non-upstream
> ("classic") Xen kernels is no longer supported.
> 
> Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
> Reviewed-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
> ---
>  kexec/Makefile                  |    1 +
>  kexec/arch/i386/crashdump-x86.c |   20 +++++-
>  kexec/crashdump-xen.c           |   34 ++++++++++
>  kexec/crashdump.h               |    3 +-
>  kexec/kexec-xen.c               |  139 
> +++++++++++++++++++++++++++++++++++++++
>  kexec/kexec.c                   |   24 +++++--
>  kexec/kexec.h                   |    5 ++
>  7 files changed, 218 insertions(+), 8 deletions(-)
>  create mode 100644 kexec/kexec-xen.c
> 

[snip]

> diff --git a/kexec/kexec-xen.c b/kexec/kexec-xen.c
> new file mode 100644
> index 0000000..77f65c0
> --- /dev/null
> +++ b/kexec/kexec-xen.c
> @@ -0,0 +1,139 @@
> +#define _GNU_SOURCE
> +#include <stdio.h>
> +#include <string.h>
> +#include <stdlib.h>
> +#include <elf.h>
> +#include "kexec.h"
> +#include "kexec-syscall.h"
> +#include "crashdump.h"
> +
> +#include "config.h"
> +
> +#ifdef HAVE_LIBXENCTRL
> +#include <xenctrl.h>
> +
> +#include "crashdump.h"
> +
> +int xen_kexec_load(struct kexec_info *info)
> +{
> +     uint32_t nr_segments = info->nr_segments;
> +     struct kexec_segment *segments = info->segment;
> +     xc_interface *xch;
> +     xc_hypercall_buffer_array_t *array = NULL;
> +     uint8_t type;
> +     uint8_t arch;
> +     xen_kexec_segment_t *xen_segs;
> +     int s;
> +     int ret = -1;
> +
> +     xch = xc_interface_open(NULL, NULL, 0);
> +     if (!xch)
> +             return -1;
> +
> +     xen_segs = calloc(nr_segments + 1, sizeof(*xen_segs));
> +     if (!xen_segs)
> +             goto out;
> +
> +     array = xc_hypercall_buffer_array_create(xch, nr_segments);
> +     if (array == NULL)
> +             goto out;
> +
> +     for (s = 0; s < nr_segments; s++) {
> +             DECLARE_HYPERCALL_BUFFER(void, seg_buf);
> +
> +             seg_buf = xc_hypercall_buffer_array_alloc(xch, array, s,
> +                                                       seg_buf, 
> segments[s].bufsz);
> +             if (seg_buf == NULL)
> +                     goto out;
> +             memcpy(seg_buf, segments[s].buf, segments[s].bufsz);
> +
> +             set_xen_guest_handle(xen_segs[s].buf.h, seg_buf);
> +             xen_segs[s].buf_size = segments[s].bufsz;
> +             xen_segs[s].dest_maddr = (uint64_t)segments[s].mem;
> +             xen_segs[s].dest_size = segments[s].memsz;
> +     }
> +
> +     /*
> +      * Ensure 0 - 1 MiB is mapped and accessible by the image.
> +      *
> +      * This allows access to the VGA memory and the region
> +      * purgatory copies in the crash case.
> +      */
> +     set_xen_guest_handle(xen_segs[s].buf.h, HYPERCALL_BUFFER_NULL);
> +     xen_segs[s].buf_size = 0;
> +     xen_segs[s].dest_maddr = 0;
> +     xen_segs[s].dest_size = 1 * 1024 * 1024;
> +     nr_segments++;
> +
> +     type = (info->kexec_flags & KEXEC_ON_CRASH) ? KEXEC_TYPE_CRASH
> +             : KEXEC_TYPE_DEFAULT;
> +
> +     arch = (info->kexec_flags & KEXEC_ARCH_MASK) >> 16;
> +#if defined(_i386__) || defined(__x86_64__)
> +     if (!arch)
> +             arch = EM_386;
> +#endif
> +
> +     ret = xc_kexec_load(xch, type, arch, (uint64_t)info->entry,
> +                         nr_segments, xen_segs);
> +
> +out:
> +     xc_hypercall_buffer_array_destroy(xch, array);
> +     free(xen_segs);
> +     xc_interface_close(xch);
> +
> +     return ret;
> +}
> +
> +int xen_kexec_unload(uint64_t kexec_flags)
> +{
> +     xc_interface *xch;
> +     uint8_t type;
> +     int ret;
> +
> +     xch = xc_interface_open(NULL, NULL, 0);
> +     if (!xch)
> +             return -1;
> +
> +     type = (kexec_flags & KEXEC_ON_CRASH) ? KEXEC_TYPE_CRASH
> +             : KEXEC_TYPE_DEFAULT;
> +
> +     ret = xc_kexec_unload(xch, type);
> +
> +     xc_interface_close(xch);
> +
> +     return ret;
> +}
> +
> +void xen_kexec_exec(void)
> +{
> +     xc_interface *xch;
> +     
> +     xch = xc_interface_open(NULL, NULL, 0);
> +     if (!xch)
> +             return;
> +
> +     xc_kexec_exec(xch, KEXEC_TYPE_DEFAULT);
> +
> +     xc_interface_close(xch);
> +}
> +
> +#else /* ! HAVE_LIBXENCTRL */
> +
> +int xen_kexec_load(uint64_t entry,
> +                uint32_t nr_segments, struct kexec_segment *segments,
> +                uint64_t kexec_flags)
> +{
> +     return -1;
> +}
> +
> +int xen_kexec_unload(uin64_t kexec_flags);
> +{
> +     return -1;
> +}
> +
> +void xen_kexec_exec(void)
> +{
> +}
> +
> +#endif

[snip]

I have applied the following follow-up patch to resolves some errors.
Let me know if I messed it up.

From: Simon Horman <horms@xxxxxxxxxxxx>

[PATCH] kexec/xen: Correct some compile errors

Correct various problems introduced by
08cf823704b0fa3b ("kexec/xen: directly load images images into Xen").

These all relate to the case here HAVE_LIBXENCTRL is not set.

Signed-off-by: Simon Horman <horms@xxxxxxxxxxxx>
---
 kexec/kexec-xen.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/kexec/kexec-xen.c b/kexec/kexec-xen.c
index 77f65c0..e885246 100644
--- a/kexec/kexec-xen.c
+++ b/kexec/kexec-xen.c
@@ -2,6 +2,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
+#include <stdlib.h>
 #include <elf.h>
 #include "kexec.h"
 #include "kexec-syscall.h"
@@ -120,14 +121,12 @@ void xen_kexec_exec(void)
 
 #else /* ! HAVE_LIBXENCTRL */
 
-int xen_kexec_load(uint64_t entry,
-                  uint32_t nr_segments, struct kexec_segment *segments,
-                  uint64_t kexec_flags)
+int xen_kexec_load(struct kexec_info *UNUSED(info))
 {
        return -1;
 }
 
-int xen_kexec_unload(uin64_t kexec_flags);
+int xen_kexec_unload(uint64_t kexec_flags)
 {
        return -1;
 }
-- 
1.8.4


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel


 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.