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Re: [PATCH v5 09/11] xen: add capability to load initrd outside of initi
From: |
Juergen Gross |
Subject: |
Re: [PATCH v5 09/11] xen: add capability to load initrd outside of initial mapping |
Date: |
Mon, 29 Feb 2016 16:49:04 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 |
On 29/02/16 16:43, Daniel Kiper wrote:
> On Mon, Feb 29, 2016 at 09:27:42AM +0100, Juergen Gross wrote:
>> On 26/02/16 16:41, Daniel Kiper wrote:
>>> On Fri, Feb 26, 2016 at 03:28:21PM +0100, Juergen Gross wrote:
>>>> On 26/02/16 15:00, Daniel Kiper wrote:
>>>>> On Thu, Feb 25, 2016 at 04:33:46PM +0100, Juergen Gross wrote:
>>>>>> On 25/02/16 13:47, Daniel Kiper wrote:
>>>>>>> On Thu, Feb 25, 2016 at 12:33:35PM +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>
>>>>>>>> ---
>>>>>>>> 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 | 65
>>>>>>>> ++++++++++++++++++++++++++++++--------
>>>>>>>> grub-core/loader/i386/xen_fileXX.c | 3 ++
>>>>>>>> include/grub/xen_file.h | 1 +
>>>>>>>> 3 files changed, 56 insertions(+), 13 deletions(-)
>>>>>>>>
>>>>>>>> diff --git a/grub-core/loader/i386/xen.c b/grub-core/loader/i386/xen.c
>>>>>>>> index 2e12763..466f0c0 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;
>>>>>>>> @@ -320,6 +329,24 @@ grub_xen_pt_alloc (void)
>>>>>>>> }
>>>>>>>>
>>>>>>>> static grub_err_t
>>>>>>>> +grub_xen_alloc_final (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;
>>>>>>>
>>>>>>> Could you move grub_xen_p2m_alloc() here? This way
>>>>>>> grub_xen_alloc_final()
>>>>>>> will be real final in patch 11 and you do not need an extra condition
>>>>>>> around grub_xen_p2m_alloc().
>>>>>>
>>>>>> No. Page tables must be allocated after p2m unless p2m is outside of
>>>>>> initial kernel mapping (patch 11).
>>>>>
>>>>> OK, I was afraid of that. However, then grub_xen_alloc_final() is not
>>>>> final.
>>>>
>>>> Sure it is. Patch 11 just adds allocation to grub_xen_alloc_final(), not
>>>> after it.
>>>
>>> Excerpt from patch 11:
>>>
>>> @@ -474,6 +503,12 @@ grub_xen_boot (void)
>>> err = grub_xen_alloc_final ();
>>> if (err)
>>> return err;
>>> + if (xen_state.xen_inf.has_p2m_base)
>>> + {
>>> + err = grub_xen_p2m_alloc ();
>>> + if (err)
>>> + return err;
>>> + }
>>>
>>
>> Hmph. No idea what I looked at when writing my previous reply.
>>
>>>>> So, maybe it should be called grub_xen_alloc_boot_data() or something
>>>>> like that.
>>>
>>> Then my previous comment is still valid.
>>
>> What about naming it grub_xen_alloc_kernel_mapping() ? This is what it
>> really does: It is allocating all not yet allocated areas which are to
>> be included in the initial kernel mapping.
>
> This function does three things:
> - allocate memory for p2m array,
> - allocate special pages (e.g. console),
> - allocate memory for page tables.
>
> Three of them are part of boot data described by struct start_info.
> Well, there are also other required stuff to properly boot PV guest.
> So, I can agree that grub_xen_alloc_boot_data() is not perfect but
> I cannot find anything better. Additionally, IMO
> grub_xen_alloc_kernel_mapping()
> is not right choice too. It suggests that this functions does anything
> with kernel mapping. Yep, it does, however, this is only one third
> of this function. So, I tend to use my proposal or anything better
> which is short and quite well describes what is going in this
> function as whole.
Yeah. grub_xen_alloc_stuff() with a nice comment. ;-)
Okay, lets stick with grub_xen_alloc_boot_data() and add a comment
explaining that the function will allocate everything not yet allocated
and covered by the initial page tables.
Juergen
- [PATCH v5 00/11] grub-xen: support booting huge pv-domains, Juergen Gross, 2016/02/25
- [PATCH v5 09/11] xen: add capability to load initrd outside of initial mapping, Juergen Gross, 2016/02/25
- Re: [PATCH v5 09/11] xen: add capability to load initrd outside of initial mapping, Daniel Kiper, 2016/02/25
- Re: [PATCH v5 09/11] xen: add capability to load initrd outside of initial mapping, Juergen Gross, 2016/02/25
- Re: [PATCH v5 09/11] xen: add capability to load initrd outside of initial mapping, Daniel Kiper, 2016/02/26
- Re: [PATCH v5 09/11] xen: add capability to load initrd outside of initial mapping, Juergen Gross, 2016/02/26
- Re: [PATCH v5 09/11] xen: add capability to load initrd outside of initial mapping, Daniel Kiper, 2016/02/26
- Re: [PATCH v5 09/11] xen: add capability to load initrd outside of initial mapping, Juergen Gross, 2016/02/29
- Re: [PATCH v5 09/11] xen: add capability to load initrd outside of initial mapping, Daniel Kiper, 2016/02/29
- Re: [PATCH v5 09/11] xen: add capability to load initrd outside of initial mapping,
Juergen Gross <=
- Re: [PATCH v5 09/11] xen: add capability to load initrd outside of initial mapping, Daniel Kiper, 2016/02/29
[PATCH v5 03/11] xen: reduce number of global variables in xen loader, Juergen Gross, 2016/02/25
[PATCH v5 07/11] xen: factor out allocation of special pages into separate function, Juergen Gross, 2016/02/25
[PATCH v5 10/11] xen: modify page table construction, Juergen Gross, 2016/02/25
[PATCH v5 06/11] xen: factor out p2m list allocation into separate function, Juergen Gross, 2016/02/25
[PATCH v5 11/11] xen: add capability to load p2m list outside of kernel mapping, Juergen Gross, 2016/02/25
[PATCH v5 05/11] xen: synchronize xen header, Juergen Gross, 2016/02/25
[PATCH v5 02/11] xen: avoid memleaks on error, Juergen Gross, 2016/02/25