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Re: [PATCH v6 09/11] xen: add capability to load initrd outside of initi
From: |
Juergen Gross |
Subject: |
Re: [PATCH v6 09/11] xen: add capability to load initrd outside of initial mapping |
Date: |
Wed, 2 Mar 2016 09:14:23 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 |
On 02/03/16 08:56, Daniel Kiper wrote:
> On Tue, Mar 01, 2016 at 08:55:09AM +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>
>> ---
>> V6: rename grub_xen_alloc_final() to grub_xen_alloc_boot_data()
>> V5: let call grub_xen_alloc_final() all subfunctions unconditionally
>> and let them decide whether they need to do anything
>> V4: rename grub_xen_alloc_end() to grub_xen_alloc_final()
>> ---
>> grub-core/loader/i386/xen.c | 66
>> ++++++++++++++++++++++++++++++--------
>> grub-core/loader/i386/xen_fileXX.c | 3 ++
>> include/grub/xen_file.h | 1 +
>> 3 files changed, 57 insertions(+), 13 deletions(-)
>>
>> diff --git a/grub-core/loader/i386/xen.c b/grub-core/loader/i386/xen.c
>> index 2e12763..989a60b 100644
>> --- a/grub-core/loader/i386/xen.c
>> +++ b/grub-core/loader/i386/xen.c
>> @@ -228,6 +228,9 @@ grub_xen_p2m_alloc (void)
>> grub_size_t p2msize;
>> grub_err_t err;
>>
>> + if (xen_state.virt_mfn_list)
>> + return GRUB_ERR_NONE;
>> +
>> xen_state.state.mfn_list = xen_state.max_addr;
>> xen_state.next_start.mfn_list =
>> xen_state.max_addr + xen_state.xen_inf.virt_base;
>> @@ -250,6 +253,9 @@ grub_xen_special_alloc (void)
>> grub_relocator_chunk_t ch;
>> grub_err_t err;
>>
>> + if (xen_state.virt_start_info)
>> + return GRUB_ERR_NONE;
>> +
>> err = grub_relocator_alloc_chunk_addr (xen_state.relocator, &ch,
>> xen_state.max_addr,
>> sizeof (xen_state.next_start));
>> @@ -281,6 +287,9 @@ grub_xen_pt_alloc (void)
>> grub_uint64_t nr_info_pages;
>> grub_uint64_t nr_pages, nr_pt_pages, nr_need_pages;
>>
>> + if (xen_state.virt_pgtable)
>> + return GRUB_ERR_NONE;
>> +
>> xen_state.next_start.pt_base =
>> xen_state.max_addr + xen_state.xen_inf.virt_base;
>> xen_state.state.paging_start = xen_state.max_addr >> PAGE_SHIFT;
>> @@ -319,6 +328,25 @@ grub_xen_pt_alloc (void)
>> return GRUB_ERR_NONE;
>> }
>>
>> +/* Allocate all not yet allocated areas mapped by initial page tables. */
>> +static grub_err_t
>> +grub_xen_alloc_boot_data (void)
>> +{
>> + grub_err_t err;
>> +
>> + err = grub_xen_p2m_alloc ();
>> + if (err)
>> + return err;
>> + err = grub_xen_special_alloc ();
>> + if (err)
>> + return err;
>> + err = grub_xen_pt_alloc ();
>> + if (err)
>> + return err;
>> +
>> + return GRUB_ERR_NONE;
>> +}
>> +
>> static grub_err_t
>> grub_xen_boot (void)
>> {
>> @@ -330,13 +358,7 @@ grub_xen_boot (void)
>> if (grub_xen_n_allocated_shared_pages)
>> return grub_error (GRUB_ERR_BUG, "active grants");
>>
>> - err = grub_xen_p2m_alloc ();
>> - if (err)
>> - return err;
>> - err = grub_xen_special_alloc ();
>> - if (err)
>> - return err;
>> - err = grub_xen_pt_alloc ();
>> + err = grub_xen_alloc_boot_data ();
>> if (err)
>> return err;
>>
>> @@ -610,6 +632,13 @@ grub_cmd_initrd (grub_command_t cmd __attribute__
>> ((unused)),
>> goto fail;
>> }
>>
>> + if (xen_state.xen_inf.unmapped_initrd)
>> + {
>> + err = grub_xen_alloc_boot_data ();
>> + if (err)
>> + goto fail;
>> + }
>> +
>> if (grub_initrd_init (argc, argv, &initrd_ctx))
>> goto fail;
>>
>> @@ -627,14 +656,24 @@ grub_cmd_initrd (grub_command_t cmd __attribute__
>> ((unused)),
>> goto fail;
>> }
>>
>> - xen_state.next_start.mod_start =
>> - xen_state.max_addr + xen_state.xen_inf.virt_base;
>> - xen_state.next_start.mod_len = size;
>
> You forgot about leaving this as is...
>
>> -
>> - xen_state.max_addr = ALIGN_UP (xen_state.max_addr + size, PAGE_SIZE);
>> + if (xen_state.xen_inf.unmapped_initrd)
>> + {
>> + xen_state.next_start.flags |= SIF_MOD_START_PFN;
>> + xen_state.next_start.mod_start = xen_state.max_addr >> PAGE_SHIFT;
>> + xen_state.next_start.mod_len = size;
>
> Then you do not need this...
>
>> + }
>> + else
>> + {
>> + xen_state.next_start.mod_start =
>> + xen_state.max_addr + xen_state.xen_inf.virt_base;
>> + xen_state.next_start.mod_len = size;
>
> ... nor this...
>
>> + }
>
> ... and even this curly brackets...
Hmm, I did this on purpose. I like it much more to have all assignments
to xen_state.next_start belonging logically together at one place. This
kind of documents that even for the unmapped case the size is still in
bytes even if the start is now a pfn.
Juergen
- [PATCH v6 00/11] grub-xen: support booting huge pv-domains, Juergen Gross, 2016/03/01
- [PATCH v6 01/11] xen: make xen loader callable multiple times, Juergen Gross, 2016/03/01
- [PATCH v6 02/11] xen: avoid memleaks on error, Juergen Gross, 2016/03/01
- [PATCH v6 04/11] xen: add elfnote.h to avoid using numbers instead of constants, Juergen Gross, 2016/03/01
- [PATCH v6 03/11] xen: reduce number of global variables in xen loader, Juergen Gross, 2016/03/01
- [PATCH v6 06/11] xen: factor out p2m list allocation into separate function, Juergen Gross, 2016/03/01
- [PATCH v6 05/11] xen: synchronize xen header, Juergen Gross, 2016/03/01
- [PATCH v6 07/11] xen: factor out allocation of special pages into separate function, Juergen Gross, 2016/03/01
- [PATCH v6 09/11] xen: add capability to load initrd outside of initial mapping, Juergen Gross, 2016/03/01
- [PATCH v6 11/11] xen: add capability to load p2m list outside of kernel mapping, Juergen Gross, 2016/03/01
- [PATCH v6 08/11] xen: factor out allocation of page tables into separate function, Juergen Gross, 2016/03/01
- [PATCH v6 10/11] xen: modify page table construction, Juergen Gross, 2016/03/01