Re: [PATCH 07/24] mmap: Add grub_mmap_get_lowest() and grub_mmap_get_highest()

[ross . philipson]

On 9/19/24 3:23 PM, Sergii Dmytruk wrote:
> Sent 0-7 and part of 11 separately taking all the comments into account:
>
>      https://lists.gnu.org/archive/html/grub-devel/2024-09/msg00194.html

Great thanks. I will look them over, thanks for doing that. This should 
make them easy to get in.

Ross

> Regards,
> Sergii
>
> On Tue, Sep 17, 2024 at 11:06:51AM -0700, Ross Philipson via Grub-devel wrote:
> > On 8/26/24 5:44 AM, Sergii Dmytruk wrote:
> > > From: Daniel Kiper <daniel.kiper@oracle.com>
> > >
> > > The functions calculate lowest and highest available RAM
> > > addresses respectively.
> > >
> > > Both functions are needed to calculate PMR boundaries for
> > > Intel TXT secure launcher introduced by subsequent patches.
> >
> > After discussing this we think the best course of action is to submit the
> > first 7 patches standalone (also see my response to patch 11 that is
> > coming). For this patch I would just remove the last sentence about TXT so
> > it is not tied to the DRTM work.
> >
> > Then you can submit this set (with the couple of the changes I suggested
> > earlier) and we can more easily get this part in.
> >
> > Thanks
> > Ross
> >
> > > Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
> > > ---
> > >    grub-core/mmap/mmap.c | 83 +++++++++++++++++++++++++++++++++++++++++++
> > >    include/grub/memory.h |  3 ++
> > >    2 files changed, 86 insertions(+)
> > >
> > > diff --git a/grub-core/mmap/mmap.c b/grub-core/mmap/mmap.c
> > > index c8c8312c5..80d6c60b8 100644
> > > --- a/grub-core/mmap/mmap.c
> > > +++ b/grub-core/mmap/mmap.c
> > > @@ -26,6 +26,7 @@
> > >    #include <grub/command.h>
> > >    #include <grub/dl.h>
> > >    #include <grub/i18n.h>
> > > +#include <grub/safemath.h>
> > >    GRUB_MOD_LICENSE ("GPLv3+");
> > > @@ -343,6 +344,88 @@ grub_mmap_unregister (int handle)
> > >    #endif /* ! GRUB_MMAP_REGISTER_BY_FIRMWARE */
> > > +typedef struct
> > > +{
> > > +  grub_uint64_t addr;
> > > +  grub_uint64_t limit;
> > > +} addr_limit_t;
> > > +
> > > +/* Helper for grub_mmap_get_lowest(). */
> > > +static int
> > > +lowest_hook (grub_uint64_t addr, grub_uint64_t size, grub_memory_type_t type,
> > > +             void *data)
> > > +{
> > > +  addr_limit_t *al = data;
> > > +  grub_uint64_t end;
> > > +
> > > +  if (type != GRUB_MEMORY_AVAILABLE)
> > > +    return 0;
> > > +
> > > +  if (grub_add (addr, size, &end))
> > > +    return 0;
> > > +
> > > +  if (addr >= al->limit)
> > > +    al->addr = grub_min (al->addr, addr);
> > > +
> > > +  if ((addr < al->limit) && (end > al->limit))
> > > +    al->addr = al->limit;
> > > +
> > > +  return 0;
> > > +}
> > > +
> > > +/*
> > > + * This function calculates lowest available RAM address that is at or above
> > > + * the passed limit.  If no RAM exists above the limit, ~0 is returned.
> > > + */
> > > +grub_uint64_t
> > > +grub_mmap_get_lowest (grub_uint64_t limit)
> > > +{
> > > +  addr_limit_t al = {~0, limit};
> > > +
> > > +  grub_mmap_iterate (lowest_hook, &al);
> > > +
> > > +  return al.addr;
> > > +}
> > > +
> > > +/* Helper for grub_mmap_get_highest(). */
> > > +static int
> > > +highest_hook (grub_uint64_t addr, grub_uint64_t size, grub_memory_type_t type,
> > > +              void *data)
> > > +{
> > > +  addr_limit_t *al = data;
> > > +  grub_uint64_t end;
> > > +
> > > +  if (type != GRUB_MEMORY_AVAILABLE)
> > > +    return 0;
> > > +
> > > +  if (grub_add (addr, size, &end))
> > > +    return 0;
> > > +
> > > +  if (end < al->limit)
> > > +    al->addr = grub_max (al->addr, end);
> > > +
> > > +  if ((addr < al->limit) && (end >= al->limit))
> > > +    al->addr = al->limit;
> > > +
> > > +  return 0;
> > > +}
> > > +
> > > +/*
> > > + * This function calculates highest available RAM address that is below the
> > > + * passed limit.  Returned address is either one byte after last byte of RAM or
> > > + * equal to limit, whichever is lower.  If no RAM exists below limit, 0 is
> > > + * returned.
> > > + */
> > > +grub_uint64_t
> > > +grub_mmap_get_highest (grub_uint64_t limit)
> > > +{
> > > +  addr_limit_t al = {0, limit};
> > > +
> > > +  grub_mmap_iterate (highest_hook, &al);
> > > +
> > > +  return al.addr;
> > > +}
> > > +
> > >    #define CHUNK_SIZE   0x400
> > >    struct badram_entry {
> > > diff --git a/include/grub/memory.h b/include/grub/memory.h
> > > index 6da114a1b..8f22f7525 100644
> > > --- a/include/grub/memory.h
> > > +++ b/include/grub/memory.h
> > > @@ -69,6 +69,9 @@ void *grub_mmap_malign_and_register (grub_uint64_t align, 
> > > grub_uint64_t size,
> > >    void grub_mmap_free_and_unregister (int handle);
> > > +extern grub_uint64_t grub_mmap_get_lowest (grub_uint64_t limit);
> > > +extern grub_uint64_t grub_mmap_get_highest (grub_uint64_t limit);
> > > +
> > >    #ifndef GRUB_MMAP_REGISTER_BY_FIRMWARE
> > >    struct grub_mmap_region