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Re: [PATCH v2 4/6] xen: add capability to load initrd outside of initial
From: |
Daniel Kiper |
Subject: |
Re: [PATCH v2 4/6] xen: add capability to load initrd outside of initial mapping |
Date: |
Thu, 11 Feb 2016 18:25:56 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Thu, Feb 11, 2016 at 03:13:40PM +0100, Juergen Gross wrote:
> On 11/02/16 13:33, Daniel Kiper wrote:
> > On Thu, Feb 11, 2016 at 08:53:24AM +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>
> >> ---
> >> grub-core/loader/i386/xen.c | 56
> >> ++++++++++++++++++++++++++++++--------
> >> grub-core/loader/i386/xen_fileXX.c | 3 ++
> >> include/grub/xen_file.h | 1 +
> >> 3 files changed, 49 insertions(+), 11 deletions(-)
> >>
> >> diff --git a/grub-core/loader/i386/xen.c b/grub-core/loader/i386/xen.c
> >> index 65cec27..0f41048 100644
> >> --- a/grub-core/loader/i386/xen.c
> >> +++ b/grub-core/loader/i386/xen.c
> >> @@ -307,15 +307,14 @@ grub_xen_pt_alloc (void)
> >> }
> >>
> >> static grub_err_t
> >> -grub_xen_boot (void)
> >> +grub_xen_alloc_end (void)
> >> {
> >> grub_err_t err;
> >> - grub_uint64_t nr_pages;
> >> - struct gnttab_set_version gnttab_setver;
> >> - grub_size_t i;
> >> + static int called = 0;
> >>
> >> - if (grub_xen_n_allocated_shared_pages)
> >> - return grub_error (GRUB_ERR_BUG, "active grants");
> >> + if (called)
> >> + return GRUB_ERR_NONE;
> >
> > Why?
>
> Did you look at the function? grub_xen_alloc_end() (some parts of the
> original grub_xen_boot()) is new and may be called multiple times. It
> was much easier to just call it and let it do what must be done only
> at the first time called.
OK, but this means that you can use this loader only once. If you make
a mistake in boot command line then you cannot fix it by calling this
loader again because grub_xen_alloc_end() will fail. Am I right?
> >> + called = 1;
> >>
> >> err = grub_xen_p2m_alloc ();
> >> if (err)
> >> @@ -327,6 +326,24 @@ grub_xen_boot (void)
> >> if (err)
> >> return err;
> >>
> >> + return GRUB_ERR_NONE;
> >> +}
> >> +
> >> +static grub_err_t
> >> +grub_xen_boot (void)
> >> +{
> >> + grub_err_t err;
> >> + grub_uint64_t nr_pages;
> >> + struct gnttab_set_version gnttab_setver;
> >> + grub_size_t i;
> >> +
> >> + if (grub_xen_n_allocated_shared_pages)
> >> + return grub_error (GRUB_ERR_BUG, "active grants");
> >
> > Why?
>
> That's how it has been before. git just decided to generate the diff
> that way.
Could you try --patience git option?
> >> + err = grub_xen_alloc_end ();
> >> + if (err)
> >> + return err;
> >> +
> >> err = set_mfns (console_pfn);
> >> if (err)
> >> return err;
> >> @@ -587,6 +604,13 @@ grub_cmd_initrd (grub_command_t cmd __attribute__
> >> ((unused)),
> >> goto fail;
> >> }
> >>
> >> + if (xen_inf.unmapped_initrd)
> >> + {
> >> + err = grub_xen_alloc_end ();
> >> + if (err)
> >> + goto fail;
> >> + }
> >> +
> >> if (grub_initrd_init (argc, argv, &initrd_ctx))
> >> goto fail;
> >>
> >> @@ -603,13 +627,22 @@ grub_cmd_initrd (grub_command_t cmd __attribute__
> >> ((unused)),
> >> goto fail;
> >> }
> >>
> >> - next_start.mod_start = max_addr + xen_inf.virt_base;
> >> - next_start.mod_len = size;
> >> -
> >> - max_addr = ALIGN_UP (max_addr + size, PAGE_SIZE);
> >> + if (xen_inf.unmapped_initrd)
> >> + {
> >> + next_start.flags |= SIF_MOD_START_PFN;
> >> + next_start.mod_start = max_addr >> PAGE_SHIFT;
> >> + next_start.mod_len = size;
> >> + }
> >> + else
> >> + {
> >> + next_start.mod_start = max_addr + xen_inf.virt_base;
> >> + next_start.mod_len = size;
> >> + }
> >>
> >> grub_dprintf ("xen", "Initrd, addr=0x%x, size=0x%x\n",
> >> - (unsigned) next_start.mod_start, (unsigned) size);
> >> + (unsigned) (max_addr + xen_inf.virt_base), (unsigned) size);
> >> +
> >> + max_addr = ALIGN_UP (max_addr + size, PAGE_SIZE);
> >>
> >> fail:
> >> grub_initrd_close (&initrd_ctx);
> >> @@ -660,6 +693,7 @@ grub_cmd_module (grub_command_t cmd __attribute__
> >> ((unused)),
> >>
> >> if (!xen_module_info_page)
> >> {
> >> + xen_inf.unmapped_initrd = 0;
> >> n_modules = 0;
> >> max_addr = ALIGN_UP (max_addr, PAGE_SIZE);
> >> modules_target_start = max_addr;
> >> diff --git a/grub-core/loader/i386/xen_fileXX.c
> >> b/grub-core/loader/i386/xen_fileXX.c
> >> index 1ba5649..69fccd2 100644
> >> --- a/grub-core/loader/i386/xen_fileXX.c
> >> +++ b/grub-core/loader/i386/xen_fileXX.c
> >> @@ -253,6 +253,9 @@ parse_note (grub_elf_t elf, struct grub_xen_file_info
> >> *xi,
> >> descsz == 2 ? 2 : 3) == 0)
> >> xi->arch = GRUB_XEN_FILE_I386;
> >> break;
> >> + case 16:
> >
> > Could you define this a constant and use it here?
>
> This would be the only case with a constant. All others are numeric
> as well.
Ugh... So, please, please fix it at first. It is not an excuse
if somebody before you made a mistake (let's call it in that way).
Or at least put comments what these values mean. However, I prefer
constants. Constants with comments (at least in header file) would
be perfect.
Daniel
- [PATCH v2 0/6] grub-xen: support booting huge pv-domains, Juergen Gross, 2016/02/11
- [PATCH v2 2/6] xen: factor out allocation of special pages into separate function, Juergen Gross, 2016/02/11
- [PATCH v2 6/6] xen: add capability to load p2m list outside of kernel mapping, Juergen Gross, 2016/02/11
- [PATCH v2 4/6] xen: add capability to load initrd outside of initial mapping, Juergen Gross, 2016/02/11
- Re: [PATCH v2 4/6] xen: add capability to load initrd outside of initial mapping, Vladimir 'φ-coder/phcoder' Serbinenko, 2016/02/12
- Re: [PATCH v2 4/6] xen: add capability to load initrd outside of initial mapping, Juergen Gross, 2016/02/12
[PATCH v2 1/6] xen: factor out p2m list allocation into separate function, Juergen Gross, 2016/02/11
[PATCH v2 3/6] xen: factor out allocation of page tables into separate function, Juergen Gross, 2016/02/11