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[PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into boot mem areas

Started byDave Young <dyoung@redhat.com>
First post2017-01-12 10:50 +0100
Last post2017-01-13 09:20 +0100
Articles 6 — 3 participants

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  [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into boot mem areas Dave Young <dyoung@redhat.com> - 2017-01-12 10:50 +0100
    Re: [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into boot mem areas Nicolai Stange <nicstange@gmail.com> - 2017-01-12 12:20 +0100
      Re: [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into  boot mem areas Dave Young <dyoung@redhat.com> - 2017-01-12 22:40 +0100
    Re: [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into  boot mem areas Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-01-12 17:20 +0100
      Re: [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into  boot mem areas Dave Young <dyoung@redhat.com> - 2017-01-12 22:30 +0100
        Re: [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into  boot mem areas Dave Young <dyoung@redhat.com> - 2017-01-13 09:20 +0100

#1557252 — [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into boot mem areas

FromDave Young <dyoung@redhat.com>
Date2017-01-12 10:50 +0100
Subject[PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into boot mem areas
Message-ID<sYKb7-2kU-15@gated-at.bofh.it>
There are memory ranges like below when I testing early efi_mem_reserve:

efi: mem62: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
efi: mem63: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
efi: mem64: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
efi: mem65: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
efi: mem66: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
efi: mem67: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)

So efi_memmap_insert will run into inserting same region multiple times,
also because efi_memmap_insert does not consider the duplicate ranges it will
cause memmap buffer overflow due to the size is pre-calculated, and kernel boot
fail with a panic.  We did not detect such issue because current users of
efi_mem_insert do it very late after switching to virtual mode, at that time
the new cooked efi.memmap contains only runtime needed memory ranges.

efi_mem_reserve cares only about boot services regions and maybe loader areas.
So add a new argument to efi_memmap_insert for this purpose.
 
Later patches depend on this one for moving bgrt reservation to early code.

Signed-off-by: Dave Young <dyoung@redhat.com>
---
 arch/x86/platform/efi/quirks.c  |    2 +-
 drivers/firmware/efi/fake_mem.c |    3 ++-
 drivers/firmware/efi/memmap.c   |    8 +++++++-
 include/linux/efi.h             |    4 ++--
 4 files changed, 12 insertions(+), 5 deletions(-)

--- linux-x86.orig/drivers/firmware/efi/memmap.c
+++ linux-x86/drivers/firmware/efi/memmap.c
@@ -213,7 +213,7 @@ int __init efi_memmap_split_count(efi_me
  * to see how large @buf needs to be.
  */
 void __init efi_memmap_insert(struct efi_memory_map *old_memmap, void *buf,
-			      struct efi_mem_range *mem)
+			      struct efi_mem_range *mem, bool boot_only)
 {
 	u64 m_start, m_end, m_attr;
 	efi_memory_desc_t *md;
@@ -246,6 +246,12 @@ void __init efi_memmap_insert(struct efi
 		start = md->phys_addr;
 		end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1;
 
+		if (boot_only && !(md->type == EFI_LOADER_DATA ||
+		    md->type == EFI_LOADER_CODE ||
+		    md->type == EFI_BOOT_SERVICES_CODE ||
+		    md->type == EFI_BOOT_SERVICES_DATA))
+			continue;
+
 		if (m_start <= start && end <= m_end)
 			md->attribute |= m_attr;
 
--- linux-x86.orig/arch/x86/platform/efi/quirks.c
+++ linux-x86/arch/x86/platform/efi/quirks.c
@@ -226,7 +226,7 @@ void __init efi_arch_mem_reserve(phys_ad
 		return;
 	}
 
-	efi_memmap_insert(&efi.memmap, new, &mr);
+	efi_memmap_insert(&efi.memmap, new, &mr, true);
 	early_memunmap(new, new_size);
 
 	efi_memmap_install(new_phys, num_entries);
--- linux-x86.orig/drivers/firmware/efi/fake_mem.c
+++ linux-x86/drivers/firmware/efi/fake_mem.c
@@ -85,7 +85,8 @@ void __init efi_fake_memmap(void)
 	}
 
 	for (i = 0; i < nr_fake_mem; i++)
-		efi_memmap_insert(&efi.memmap, new_memmap, &fake_mems[i]);
+		efi_memmap_insert(&efi.memmap, new_memmap, &fake_mems[i],
+				  false);
 
 	/* swap into new EFI memmap */
 	early_memunmap(new_memmap, efi.memmap.desc_size * new_nr_map);
--- linux-x86.orig/include/linux/efi.h
+++ linux-x86/include/linux/efi.h
@@ -957,8 +957,8 @@ extern int __init efi_memmap_install(phy
 extern int __init efi_memmap_split_count(efi_memory_desc_t *md,
 					 struct range *range);
 extern void __init efi_memmap_insert(struct efi_memory_map *old_memmap,
-				     void *buf, struct efi_mem_range *mem);
-
+				     void *buf, struct efi_mem_range *mem,
+				     bool boot_only);
 extern int efi_config_init(efi_config_table_type_t *arch_tables);
 #ifdef CONFIG_EFI_ESRT
 extern void __init efi_esrt_init(void);

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#1557369

FromNicolai Stange <nicstange@gmail.com>
Date2017-01-12 12:20 +0100
Message-ID<sYLAd-3jp-5@gated-at.bofh.it>
In reply to#1557252
Hi Dave,

On Thu, Jan 12 2017, Dave Young wrote:

> efi_mem_reserve cares only about boot services regions and maybe loader areas.
> So add a new argument to efi_memmap_insert for this purpose.

Please see below.


> --- linux-x86.orig/drivers/firmware/efi/memmap.c
> +++ linux-x86/drivers/firmware/efi/memmap.c
> @@ -213,7 +213,7 @@ int __init efi_memmap_split_count(efi_me
>   * to see how large @buf needs to be.
>   */
>  void __init efi_memmap_insert(struct efi_memory_map *old_memmap, void *buf,
> -			      struct efi_mem_range *mem)
> +			      struct efi_mem_range *mem, bool boot_only)
>  {
>  	u64 m_start, m_end, m_attr;
>  	efi_memory_desc_t *md;
> @@ -246,6 +246,12 @@ void __init efi_memmap_insert(struct efi
>  		start = md->phys_addr;
>  		end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1;
>  
> +		if (boot_only && !(md->type == EFI_LOADER_DATA ||
> +		    md->type == EFI_LOADER_CODE ||
> +		    md->type == EFI_BOOT_SERVICES_CODE ||
> +		    md->type == EFI_BOOT_SERVICES_DATA))
> +			continue;
> +


Actually, the efi_mem_desc_lookup() called from
efi_arch_memmap_reserve() will only return mds not satisfying the
following condition:

  if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
      md->type != EFI_BOOT_SERVICES_DATA &&
      md->type != EFI_RUNTIME_SERVICES_DATA) {
  	continue;
  }

Furthermore, efi_arch_mem_reserve() will only accept ranges fully
contained within such a region.

I think we can make efi_arch_mem_reserve() return early if
EFI_MEMORY_RUNTIME has been set already and thus, neglect this case in
efi_memmap_insert().

I suppose that we don't want to reserve within EFI_RUNTIME_SERVICES_DATA
regions in efi_mem_reserve() either -- these won't ever get made
available as general memory anyway [1]. So efi_arch_mem_reserve() should
return early here as well imo.

So, what would remain to be handled from efi_memmap_insert() in case of
boot_only would be EFI_BOOT_SERVICES_DATA only?

(As a sidenote, Matt pointed out at [1] that the EFI_LOADER_* regions
 should be reserved early through memblock_reserve() and not through
 efi_mem_reserve()).

Thanks,

Nicolai


[1] http://lkml.kernel.org/r/20170109130702.GI16838@codeblueprint.co.uk

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#1557831 — Re: [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into boot mem areas

FromDave Young <dyoung@redhat.com>
Date2017-01-12 22:40 +0100
SubjectRe: [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into boot mem areas
Message-ID<sYVge-Ak-25@gated-at.bofh.it>
In reply to#1557369
On 01/12/17 at 12:15pm, Nicolai Stange wrote:
> Hi Dave,
> 
> On Thu, Jan 12 2017, Dave Young wrote:
> 
> > efi_mem_reserve cares only about boot services regions and maybe loader areas.
> > So add a new argument to efi_memmap_insert for this purpose.
> 
> Please see below.
> 
> 
> > --- linux-x86.orig/drivers/firmware/efi/memmap.c
> > +++ linux-x86/drivers/firmware/efi/memmap.c
> > @@ -213,7 +213,7 @@ int __init efi_memmap_split_count(efi_me
> >   * to see how large @buf needs to be.
> >   */
> >  void __init efi_memmap_insert(struct efi_memory_map *old_memmap, void *buf,
> > -			      struct efi_mem_range *mem)
> > +			      struct efi_mem_range *mem, bool boot_only)
> >  {
> >  	u64 m_start, m_end, m_attr;
> >  	efi_memory_desc_t *md;
> > @@ -246,6 +246,12 @@ void __init efi_memmap_insert(struct efi
> >  		start = md->phys_addr;
> >  		end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1;
> >  
> > +		if (boot_only && !(md->type == EFI_LOADER_DATA ||
> > +		    md->type == EFI_LOADER_CODE ||
> > +		    md->type == EFI_BOOT_SERVICES_CODE ||
> > +		    md->type == EFI_BOOT_SERVICES_DATA))
> > +			continue;
> > +
> 
> 
> Actually, the efi_mem_desc_lookup() called from
> efi_arch_memmap_reserve() will only return mds not satisfying the
> following condition:
> 
>   if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
>       md->type != EFI_BOOT_SERVICES_DATA &&
>       md->type != EFI_RUNTIME_SERVICES_DATA) {
>   	continue;
>   }
> 
> Furthermore, efi_arch_mem_reserve() will only accept ranges fully
> contained within such a region.
> 
> I think we can make efi_arch_mem_reserve() return early if
> EFI_MEMORY_RUNTIME has been set already and thus, neglect this case in
> efi_memmap_insert().
> 
> I suppose that we don't want to reserve within EFI_RUNTIME_SERVICES_DATA
> regions in efi_mem_reserve() either -- these won't ever get made
> available as general memory anyway [1]. So efi_arch_mem_reserve() should
> return early here as well imo.
> 
> So, what would remain to be handled from efi_memmap_insert() in case of
> boot_only would be EFI_BOOT_SERVICES_DATA only?

It sounds reasonable though I'm still not sure about EFI_LOADER*.

The main purpose of this patch is to address the invalid mem ranges
case. As Ard mentioned I will test with Peter's patch first, if it works
fine I would like to either drop this patch as a future improvement or add
it at the end of the next post.

Matt, what's your opinion about the boot_only check and the EFI_LOADERS*
question?

> 
> (As a sidenote, Matt pointed out at [1] that the EFI_LOADER_* regions
>  should be reserved early through memblock_reserve() and not through
>  efi_mem_reserve()).
> 
> Thanks,
> 
> Nicolai
> 
> 
> [1] http://lkml.kernel.org/r/20170109130702.GI16838@codeblueprint.co.uk

Thanks
Dave

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#1557563 — Re: [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into boot mem areas

FromArd Biesheuvel <ard.biesheuvel@linaro.org>
Date2017-01-12 17:20 +0100
SubjectRe: [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into boot mem areas
Message-ID<sYQgx-66R-3@gated-at.bofh.it>
In reply to#1557252
Hello Dave,

On 12 January 2017 at 09:41, Dave Young <dyoung@redhat.com> wrote:
> There are memory ranges like below when I testing early efi_mem_reserve:
>
> efi: mem62: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
> efi: mem63: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
> efi: mem64: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
> efi: mem65: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
> efi: mem66: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
> efi: mem67: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
>

Did you spot Peter's patch to prune invalid memmap entries?

https://git.kernel.org/cgit/linux/kernel/git/efi/efi.git/commit/?h=next&id=b2a91a35445229

I would expect this patch to no longer be necessary with that in place, no?


> So efi_memmap_insert will run into inserting same region multiple times,
> also because efi_memmap_insert does not consider the duplicate ranges it will
> cause memmap buffer overflow due to the size is pre-calculated, and kernel boot
> fail with a panic.  We did not detect such issue because current users of
> efi_mem_insert do it very late after switching to virtual mode, at that time
> the new cooked efi.memmap contains only runtime needed memory ranges.
>
> efi_mem_reserve cares only about boot services regions and maybe loader areas.
> So add a new argument to efi_memmap_insert for this purpose.
>
> Later patches depend on this one for moving bgrt reservation to early code.
>
> Signed-off-by: Dave Young <dyoung@redhat.com>
> ---
>  arch/x86/platform/efi/quirks.c  |    2 +-
>  drivers/firmware/efi/fake_mem.c |    3 ++-
>  drivers/firmware/efi/memmap.c   |    8 +++++++-
>  include/linux/efi.h             |    4 ++--
>  4 files changed, 12 insertions(+), 5 deletions(-)
>
> --- linux-x86.orig/drivers/firmware/efi/memmap.c
> +++ linux-x86/drivers/firmware/efi/memmap.c
> @@ -213,7 +213,7 @@ int __init efi_memmap_split_count(efi_me
>   * to see how large @buf needs to be.
>   */
>  void __init efi_memmap_insert(struct efi_memory_map *old_memmap, void *buf,
> -                             struct efi_mem_range *mem)
> +                             struct efi_mem_range *mem, bool boot_only)
>  {
>         u64 m_start, m_end, m_attr;
>         efi_memory_desc_t *md;
> @@ -246,6 +246,12 @@ void __init efi_memmap_insert(struct efi
>                 start = md->phys_addr;
>                 end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1;
>
> +               if (boot_only && !(md->type == EFI_LOADER_DATA ||
> +                   md->type == EFI_LOADER_CODE ||
> +                   md->type == EFI_BOOT_SERVICES_CODE ||
> +                   md->type == EFI_BOOT_SERVICES_DATA))
> +                       continue;
> +
>                 if (m_start <= start && end <= m_end)
>                         md->attribute |= m_attr;
>
> --- linux-x86.orig/arch/x86/platform/efi/quirks.c
> +++ linux-x86/arch/x86/platform/efi/quirks.c
> @@ -226,7 +226,7 @@ void __init efi_arch_mem_reserve(phys_ad
>                 return;
>         }
>
> -       efi_memmap_insert(&efi.memmap, new, &mr);
> +       efi_memmap_insert(&efi.memmap, new, &mr, true);
>         early_memunmap(new, new_size);
>
>         efi_memmap_install(new_phys, num_entries);
> --- linux-x86.orig/drivers/firmware/efi/fake_mem.c
> +++ linux-x86/drivers/firmware/efi/fake_mem.c
> @@ -85,7 +85,8 @@ void __init efi_fake_memmap(void)
>         }
>
>         for (i = 0; i < nr_fake_mem; i++)
> -               efi_memmap_insert(&efi.memmap, new_memmap, &fake_mems[i]);
> +               efi_memmap_insert(&efi.memmap, new_memmap, &fake_mems[i],
> +                                 false);
>
>         /* swap into new EFI memmap */
>         early_memunmap(new_memmap, efi.memmap.desc_size * new_nr_map);
> --- linux-x86.orig/include/linux/efi.h
> +++ linux-x86/include/linux/efi.h
> @@ -957,8 +957,8 @@ extern int __init efi_memmap_install(phy
>  extern int __init efi_memmap_split_count(efi_memory_desc_t *md,
>                                          struct range *range);
>  extern void __init efi_memmap_insert(struct efi_memory_map *old_memmap,
> -                                    void *buf, struct efi_mem_range *mem);
> -
> +                                    void *buf, struct efi_mem_range *mem,
> +                                    bool boot_only);
>  extern int efi_config_init(efi_config_table_type_t *arch_tables);
>  #ifdef CONFIG_EFI_ESRT
>  extern void __init efi_esrt_init(void);
>
>

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#1557823 — Re: [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into boot mem areas

FromDave Young <dyoung@redhat.com>
Date2017-01-12 22:30 +0100
SubjectRe: [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into boot mem areas
Message-ID<sYV6y-xa-15@gated-at.bofh.it>
In reply to#1557563
On 01/12/17 at 04:15pm, Ard Biesheuvel wrote:
> Hello Dave,
> 
> On 12 January 2017 at 09:41, Dave Young <dyoung@redhat.com> wrote:
> > There are memory ranges like below when I testing early efi_mem_reserve:
> >
> > efi: mem62: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
> > efi: mem63: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
> > efi: mem64: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
> > efi: mem65: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
> > efi: mem66: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
> > efi: mem67: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
> >
> 
> Did you spot Peter's patch to prune invalid memmap entries?
> 
> https://git.kernel.org/cgit/linux/kernel/git/efi/efi.git/commit/?h=next&id=b2a91a35445229
> 
> I would expect this patch to no longer be necessary with that in place, no?

Ard, good suggestion, I did not notice that patch, will try. Actually
I'm not sure about fake_mem handling, if we can filter out the invalid
ranges then it will be natural to drop this one after a test.

Thanks
Dave

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#1558099 — Re: [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into boot mem areas

FromDave Young <dyoung@redhat.com>
Date2017-01-13 09:20 +0100
SubjectRe: [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into boot mem areas
Message-ID<sZ5fA-6Wf-7@gated-at.bofh.it>
In reply to#1557823
On 01/13/17 at 05:20am, Dave Young wrote:
> On 01/12/17 at 04:15pm, Ard Biesheuvel wrote:
> > Hello Dave,
> > 
> > On 12 January 2017 at 09:41, Dave Young <dyoung@redhat.com> wrote:
> > > There are memory ranges like below when I testing early efi_mem_reserve:
> > >
> > > efi: mem62: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
> > > efi: mem63: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
> > > efi: mem64: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
> > > efi: mem65: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
> > > efi: mem66: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
> > > efi: mem67: [Reserved           |   |  |  |  |  |  |  |   |  |  |  |  ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
> > >
> > 
> > Did you spot Peter's patch to prune invalid memmap entries?
> > 
> > https://git.kernel.org/cgit/linux/kernel/git/efi/efi.git/commit/?h=next&id=b2a91a35445229
> > 
> > I would expect this patch to no longer be necessary with that in place, no?
> 
> Ard, good suggestion, I did not notice that patch, will try. Actually
> I'm not sure about fake_mem handling, if we can filter out the invalid
> ranges then it will be natural to drop this one after a test.

The commit works for me. I updated the series.

I addressed comments known, moved patch 1 to 4/4 with only boot service
(dropped loader areas checking), I plan to send them out next Monday
see if there are more comments. 

If anyone who want to try them now, feel free to download from below url:
http://people.redhat.com/~ruyang/efi-bgrt/

Thanks
Dave

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