[PATCH 1/2] zboot: enable arm64 kexec_load for zboot image

[Dave Young]

Hi,

On Wed, 13 Sept 2023 at 08:54, Pingfan Liu <piliu at redhat.com> wrote:
>
> On Mon, Sep 11, 2023 at 6:37 PM Dave Young <dyoung at redhat.com> wrote:
> >
> > kexec_file_load support of zboot kernel image decompressed the vmlinuz,
> > so in kexec_load code just load the kernel with reading the decompressed
> > kernel fd into a new buffer and use it directly.
> >
> > Signed-off-by: Dave Young <dyoung at redhat.com>
> > ---
> >  include/kexec-pe-zboot.h               |  3 ++-
> >  kexec/arch/arm64/kexec-vmlinuz-arm64.c | 20 ++++++++++++++++++--
> >  kexec/kexec-pe-zboot.c                 |  4 +++-
> >  kexec/kexec.c                          |  2 +-
> >  kexec/kexec.h                          |  1 +
> >  5 files changed, 25 insertions(+), 5 deletions(-)
> >
> > diff --git a/include/kexec-pe-zboot.h b/include/kexec-pe-zboot.h
> > index e2e0448a81f2..374916cbe883 100644
> > --- a/include/kexec-pe-zboot.h
> > +++ b/include/kexec-pe-zboot.h
> > @@ -11,5 +11,6 @@ struct linux_pe_zboot_header {
> >         uint32_t compress_type;
> >  };
> >
> > -int pez_prepare(const char *crude_buf, off_t buf_sz, int *kernel_fd);
> > +int pez_prepare(const char *crude_buf, off_t buf_sz, int *kernel_fd,
> > +               off_t *kernel_size);
> >  #endif
> > diff --git a/kexec/arch/arm64/kexec-vmlinuz-arm64.c b/kexec/arch/arm64/kexec-vmlinuz-arm64.c
> > index c0ee47c8f50a..8f378d8fa6d0 100644
> > --- a/kexec/arch/arm64/kexec-vmlinuz-arm64.c
> > +++ b/kexec/arch/arm64/kexec-vmlinuz-arm64.c
> > @@ -34,6 +34,7 @@
> >  #include "arch/options.h"
> >
> >  static int kernel_fd = -1;
> > +static off_t decompressed_size;
> >
> >  /* Returns:
> >   * -1 : in case of error/invalid format (not a valid PE+compressed ZBOOT format.
> > @@ -72,7 +73,7 @@ int pez_arm64_probe(const char *kernel_buf, off_t kernel_size)
> >                 return -1;
> >         }
> >
> > -       ret = pez_prepare(buf, buf_sz, &kernel_fd);
> > +       ret = pez_prepare(buf, buf_sz, &kernel_fd, &decompressed_size);
> >
> >         if (!ret) {
> >             /* validate the arm64 specific header */
> > @@ -98,8 +99,23 @@ bad_header:
> >  int pez_arm64_load(int argc, char **argv, const char *buf, off_t len,
> >                         struct kexec_info *info)
> >  {
> > +       char *kbuf;
> > +
> >         info->kernel_fd = kernel_fd;
> > -       return image_arm64_load(argc, argv, buf, len, info);
> > +       if (kernel_fd > 0 && decompressed_size > 0) {
> > +               off_t nread;
> > +
> > +               kbuf = slurp_fd(kernel_fd, NULL, decompressed_size, &nread);
> > +               if (!kbuf || nread != decompressed_size) {

Today in another test I found that this breaks the kexec_file_load
because the slurp_fd() closed the kernel_fd after readding out the
buffer,  I will send another version soon, also cleanup a bit about
this function.

Thanks for reviewing.

> > +                       dbgprintf("%s: failed.\n", __func__);
> > +                       return -1;
> > +               }
> > +       } else {
> > +               dbgprintf("%s: wrong file descriptor.\n", __func__);
> > +               return -1;
> > +       }
> > +
> > +       return image_arm64_load(argc, argv, kbuf, decompressed_size, info);
> >  }
> >
> >  void pez_arm64_usage(void)
> > diff --git a/kexec/kexec-pe-zboot.c b/kexec/kexec-pe-zboot.c
> > index 2f2e052b76c5..3abd17d9fe59 100644
> > --- a/kexec/kexec-pe-zboot.c
> > +++ b/kexec/kexec-pe-zboot.c
> > @@ -37,7 +37,8 @@
> >   *
> >   * crude_buf: the content, which is read from the kernel file without any processing
> >   */
> > -int pez_prepare(const char *crude_buf, off_t buf_sz, int *kernel_fd)
> > +int pez_prepare(const char *crude_buf, off_t buf_sz, int *kernel_fd,
> > +               off_t *kernel_size)
> >  {
> >         int ret = -1;
> >         int fd = 0;
> > @@ -110,6 +111,7 @@ int pez_prepare(const char *crude_buf, off_t buf_sz, int *kernel_fd)
> >                 goto fail_bad_header;
> >         }
> >
> > +       *kernel_size = decompressed_size;
> >         dbgprintf("%s: done\n", __func__);
> >
> >         ret = 0;
> > diff --git a/kexec/kexec.c b/kexec/kexec.c
> > index c3b182e254e0..1edbd349c86d 100644
> > --- a/kexec/kexec.c
> > +++ b/kexec/kexec.c
> > @@ -489,7 +489,7 @@ static int add_backup_segments(struct kexec_info *info,
> >         return 0;
> >  }
> >
> > -static char *slurp_fd(int fd, const char *filename, off_t size, off_t *nread)
> > +char *slurp_fd(int fd, const char *filename, off_t size, off_t *nread)
> >  {
> >         char *buf;
> >         off_t progress;
> > diff --git a/kexec/kexec.h b/kexec/kexec.h
> > index ed3b499a80f2..093338969c57 100644
> > --- a/kexec/kexec.h
> > +++ b/kexec/kexec.h
> > @@ -267,6 +267,7 @@ extern void die(const char *fmt, ...)
> >         __attribute__ ((format (printf, 1, 2)));
> >  extern void *xmalloc(size_t size);
> >  extern void *xrealloc(void *ptr, size_t size);
> > +extern char *slurp_fd(int fd, const char *filename, off_t size, off_t *nread);
> >  extern char *slurp_file(const char *filename, off_t *r_size);
> >  extern char *slurp_file_mmap(const char *filename, off_t *r_size);
> >  extern char *slurp_file_len(const char *filename, off_t size, off_t *nread);
> > --
> > 2.37.2
> >
>
> LGTM,
> Reviewed-by: Pingfan Liu <piliu at redhat.com>
>