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Re: [PATCH v4 09/11] xen: add capability to load initrd outside of initi
From: |
Juergen Gross |
Subject: |
Re: [PATCH v4 09/11] xen: add capability to load initrd outside of initial mapping |
Date: |
Mon, 22 Feb 2016 10:18:38 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 |
On 22/02/16 09:42, Daniel Kiper wrote:
> On Mon, Feb 22, 2016 at 07:03:17AM +0100, Juergen Gross wrote:
>> Modern pvops linux kernels support an initrd not covered by the initial
>> mapping. This capability is flagged by an elf-note.
>>
>> In case the elf-note is set by the kernel don't place the initrd into
>> the initial mapping. This will allow to load larger initrds and/or
>> support domains with larger memory, as the initial mapping is limited
>> to 2GB and it is containing the p2m list.
>>
>> Signed-off-by: Juergen Gross <address@hidden>
>> Reviewed-by: Daniel Kiper <address@hidden>
>> ---
>> V4: rename grub_xen_alloc_end() to grub_xen_alloc_final()
>> ---
>> grub-core/loader/i386/xen.c | 61
>> ++++++++++++++++++++++++++++++--------
>> grub-core/loader/i386/xen_fileXX.c | 3 ++
>> include/grub/xen_file.h | 1 +
>> 3 files changed, 52 insertions(+), 13 deletions(-)
>>
>> diff --git a/grub-core/loader/i386/xen.c b/grub-core/loader/i386/xen.c
>> index 2e12763..22a94ae 100644
>> --- a/grub-core/loader/i386/xen.c
>> +++ b/grub-core/loader/i386/xen.c
>> @@ -58,6 +58,7 @@ struct xen_loader_state {
>> grub_uint64_t modules_target_start;
>> grub_size_t n_modules;
>> int loaded;
>> + int alloc_end_called;
>
> alloc_end_called -> alloc_final_called
>
>> };
>>
>> static struct xen_loader_state xen_state;
>> @@ -320,6 +321,28 @@ grub_xen_pt_alloc (void)
>> }
>>
>> static grub_err_t
>> +grub_xen_alloc_final (void)
>> +{
>> + grub_err_t err;
>> +
>> + if (xen_state.alloc_end_called)
>> + return GRUB_ERR_NONE;
>> + xen_state.alloc_end_called = 1;
>
> This is not nice. What happens if grub_xen_p2m_alloc() allocate what
> is needed and grub_xen_special_alloc() fails?
Then grub_xen_alloc_final will fail resulting in boot failure of the
new kernel. The memory allocated by the single functions will be freed
in case a new boot is attempted (patch 1 and 2).
> Maybe grub_xen_p2m_alloc(), grub_xen_special_alloc() and grub_xen_pt_alloc()
> should check itself that required regions are allocated properly
> (if (something != NULL)) and do nothing if yes.
Hmm, with grub_xen_reset() doing appropriate cleanups this would be an
option. I think I'll change it as you are suggesting.
Juergen
[PATCH v4 01/11] xen: make xen loader callable multiple times, Juergen Gross, 2016/02/22
[PATCH v4 05/11] xen: synchronize xen header, Juergen Gross, 2016/02/22
[PATCH v4 11/11] xen: add capability to load p2m list outside of kernel mapping, Juergen Gross, 2016/02/22
[PATCH v4 06/11] xen: factor out p2m list allocation into separate function, Juergen Gross, 2016/02/22
[PATCH v4 04/11] xen: add elfnote.h to avoid using numbers instead of constants, Juergen Gross, 2016/02/22
[PATCH v4 03/11] xen: reduce number of global variables in xen loader, Juergen Gross, 2016/02/22
[PATCH v4 10/11] xen: modify page table construction, Juergen Gross, 2016/02/22