Re: [Xen-devel] [PATCH] kexec-tools: Read always one vmcoreinfo file

[Petr Tesarik <ptesarik@xxxxxxx>]

Dne Ät 5. Äervence 2012 14:16:35 Daniel Kiper napsal(a):
> vmcoreinfo file could exists under /sys/kernel (valid on baremetal only)
> and/or under /sys/hypervisor (valid when Xen dom0 is running).
> Read only one of them. It means that only one PT_NOTE will be
> always created. Remove extra code for second PT_NOTE creation.

Hi Daniel,

are you absolutely sure this is the right thing to do? IIUC these two 
VMCORINFO notes are very different. The one from /sys/kernel/vmcoreinfo 
describes the Dom0 kernel (type 'VMCOREINFO'), while the one from 
/sys/hypervisor describes the Xen hypervisor (type 'XEN_VMCOREINFO'). If you 
keep only the hypervisor note, then e.g. makedumpfile won't be able to use 
dumplevel greater than 1, nor will it be able to extract the log buffer.

Petr Tesarik
SUSE Linux

> Signed-off-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
> ---
>  kexec/crashdump-elf.c |   33 +++++++--------------------------
>  1 files changed, 7 insertions(+), 26 deletions(-)
> 
> diff --git a/kexec/crashdump-elf.c b/kexec/crashdump-elf.c
> index 8d82db9..ec66548 100644
> --- a/kexec/crashdump-elf.c
> +++ b/kexec/crashdump-elf.c
> @@ -40,8 +40,6 @@ int FUNC(struct kexec_info *info,
>       uint64_t notes_addr, notes_len;
>       uint64_t vmcoreinfo_addr, vmcoreinfo_len;
>       int has_vmcoreinfo = 0;
> -     uint64_t vmcoreinfo_addr_xen, vmcoreinfo_len_xen;
> -     int has_vmcoreinfo_xen = 0;
>       int (*get_note_info)(int cpu, uint64_t *addr, uint64_t *len);
> 
>       if (xen_present())
> @@ -53,16 +51,14 @@ int FUNC(struct kexec_info *info,
>               return -1;
>       }
> 
> -     if (get_kernel_vmcoreinfo(&vmcoreinfo_addr, &vmcoreinfo_len) == 0) {
> -             has_vmcoreinfo = 1;
> -     }
> -
> -     if (xen_present() &&
> -         get_xen_vmcoreinfo(&vmcoreinfo_addr_xen, &vmcoreinfo_len_xen) == 0) 
> {
> -             has_vmcoreinfo_xen = 1;
> -     }
> +     if (xen_present()) {
> +             if (!get_xen_vmcoreinfo(&vmcoreinfo_addr, &vmcoreinfo_len))
> +                     has_vmcoreinfo = 1;
> +     } else
> +             if (!get_kernel_vmcoreinfo(&vmcoreinfo_addr, &vmcoreinfo_len))
> +                     has_vmcoreinfo = 1;
> 
> -     sz = sizeof(EHDR) + (nr_cpus + has_vmcoreinfo + has_vmcoreinfo_xen) *
> sizeof(PHDR) + +      sz = sizeof(EHDR) + (nr_cpus + has_vmcoreinfo) *
> sizeof(PHDR) +
>            ranges * sizeof(PHDR);
> 
>       /*
> @@ -179,21 +175,6 @@ int FUNC(struct kexec_info *info,
>               dbgprintf_phdr("vmcoreinfo header", phdr);
>       }
> 
> -     if (has_vmcoreinfo_xen) {
> -             phdr = (PHDR *) bufp;
> -             bufp += sizeof(PHDR);
> -             phdr->p_type    = PT_NOTE;
> -             phdr->p_flags   = 0;
> -             phdr->p_offset  = phdr->p_paddr = vmcoreinfo_addr_xen;
> -             phdr->p_vaddr   = 0;
> -             phdr->p_filesz  = phdr->p_memsz = vmcoreinfo_len_xen;
> -             /* Do we need any alignment of segments? */
> -             phdr->p_align   = 0;
> -
> -             (elf->e_phnum)++;
> -             dbgprintf_phdr("vmcoreinfo_xen header", phdr);
> -     }
> -
>       /* Setup an PT_LOAD type program header for the region where
>        * Kernel is mapped if elf_info->kern_size is non-zero.
>        */

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