2024-01-31 00:04:43

by Jiri Bohac

Subject: [PATCH] x86: don't reserve SETUP_RNG_SEED in e820

SETUP_RNG_SEED in setup_data is supplied by kexec and should
not be reserved in the e820 map.

Doing so reserves 16 bytes of RAM when booting with kexec.
(16 bytes because data->len is zeroed by parse_setup_data so only
sizeof(setup_data) is reserved.)

When kexec is used repeatedly, each boot adds two entries in the
kexec-provided e820 map as the 16-byte range splits a larger
range of usable memory. Eventually all of the 128 available entries
get used up. The next split will result in losing usable memory
as the new entries cannot be added to the e820 map.

Fixes: 68b8e9713c8e ("x86/setup: Use rng seeds from setup_data")
Signed-off-by: Jiri Bohac <[email protected]>
---
arch/x86/kernel/e820.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 91ade749f184..7be1362a31aa 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1018,10 +1018,12 @@ void __init e820__reserve_setup_data(void)
e820__range_update(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);

/*
- * SETUP_EFI and SETUP_IMA are supplied by kexec and do not need
- * to be reserved.
+ * SETUP_EFI, SETUP_IMA and SETUP_RNG_SEED are supplied by
+ * kexec and do not need to be reserved.
*/
- if (data->type != SETUP_EFI && data->type != SETUP_IMA)
+ if (data->type != SETUP_EFI &&
+ data->type != SETUP_IMA &&
+ data->type != SETUP_RNG_SEED)
e820__range_update_kexec(pa_data,
sizeof(*data) + data->len,
E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
--
Jiri Bohac <[email protected]>
SUSE Labs, Prague, Czechia

2024-02-28 09:46:24

by Jiri Bohac

Subject: Re: [PATCH RESEND] x86: don't reserve SETUP_RNG_SEED in e820

Adding Andrew Morton - have I been sending this to the wrong people/lists?

On Tue, Feb 20, 2024 at 02:55:27PM +0100, Jiri Bohac wrote:
> SETUP_RNG_SEED in setup_data is supplied by kexec and should
> not be reserved in the e820 map.
>
> Doing so reserves 16 bytes of RAM when booting with kexec.
> (16 bytes because data->len is zeroed by parse_setup_data so only
> sizeof(setup_data) is reserved.)
>
> When kexec is used repeatedly, each boot adds two entries in the
> kexec-provided e820 map as the 16-byte range splits a larger
> range of usable memory. Eventually all of the 128 available entries
> get used up. The next split will result in losing usable memory
> as the new entries cannot be added to the e820 map.
>
> Fixes: 68b8e9713c8e ("x86/setup: Use rng seeds from setup_data")
> Signed-off-by: Jiri Bohac <[email protected]>
> ---
> arch/x86/kernel/e820.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
> index 91ade749f184..7be1362a31aa 100644
> --- a/arch/x86/kernel/e820.c
> +++ b/arch/x86/kernel/e820.c
> @@ -1018,10 +1018,12 @@ void __init e820__reserve_setup_data(void)
> e820__range_update(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
>
> /*
> - * SETUP_EFI and SETUP_IMA are supplied by kexec and do not need
> - * to be reserved.
> + * SETUP_EFI, SETUP_IMA and SETUP_RNG_SEED are supplied by
> + * kexec and do not need to be reserved.
> */
> - if (data->type != SETUP_EFI && data->type != SETUP_IMA)
> + if (data->type != SETUP_EFI &&
> + data->type != SETUP_IMA &&
> + data->type != SETUP_RNG_SEED)
> e820__range_update_kexec(pa_data,
> sizeof(*data) + data->len,
> E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);

--
Jiri Bohac <[email protected]>
SUSE Labs, Prague, Czechia

2024-02-28 10:28:24

by tip-bot2 for Jacob Pan

Subject: [tip: x86/urgent] x86/e820: Don't reserve SETUP_RNG_SEED in e820

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID: 9e1daa3bfcccf79ee368061d807ff541d6e2d909
Gitweb: https://git.kernel.org/tip/9e1daa3bfcccf79ee368061d807ff541d6e2d909
Author: Jiri Bohac <[email protected]>
AuthorDate: Wed, 31 Jan 2024 01:04:28 +01:00
Committer: Borislav Petkov (AMD) <[email protected]>
CommitterDate: Wed, 28 Feb 2024 11:10:31 +01:00

x86/e820: Don't reserve SETUP_RNG_SEED in e820

SETUP_RNG_SEED in setup_data is supplied by kexec and should
not be reserved in the e820 map.

Doing so reserves 16 bytes of RAM when booting with kexec.
(16 bytes because data->len is zeroed by parse_setup_data so only
sizeof(setup_data) is reserved.)

When kexec is used repeatedly, each boot adds two entries in the
kexec-provided e820 map as the 16-byte range splits a larger
range of usable memory. Eventually all of the 128 available entries
get used up. The next split will result in losing usable memory
as the new entries cannot be added to the e820 map.

Fixes: 68b8e9713c8e ("x86/setup: Use rng seeds from setup_data")
Signed-off-by: Jiri Bohac <[email protected]>
Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Cc: <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/kernel/e820.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index fb8cf95..b66f540 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1017,10 +1017,12 @@ void __init e820__reserve_setup_data(void)
e820__range_update(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);

/*
- * SETUP_EFI and SETUP_IMA are supplied by kexec and do not need
- * to be reserved.
+ * SETUP_EFI, SETUP_IMA and SETUP_RNG_SEED are supplied by
+ * kexec and do not need to be reserved.
*/
- if (data->type != SETUP_EFI && data->type != SETUP_IMA)
+ if (data->type != SETUP_EFI &&
+ data->type != SETUP_IMA &&
+ data->type != SETUP_RNG_SEED)
e820__range_update_kexec(pa_data,
sizeof(*data) + data->len,
E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);

2024-02-28 10:44:06

by Borislav Petkov

Subject: Re: [PATCH RESEND] x86: don't reserve SETUP_RNG_SEED in e820

On Wed, Feb 28, 2024 at 10:45:02AM +0100, Jiri Bohac wrote:
> Adding Andrew Morton - have I been sending this to the wrong people/lists?

You're experiencing people trying to drink from the water hose...

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette

2024-03-01 18:13:17

by tip-bot2 for Jacob Pan

Subject: [tip: x86/urgent] x86/e820: Don't reserve SETUP_RNG_SEED in e820

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID: 1a2cbc38b74f10c11837f88475d683c69c8503f6
Gitweb: https://git.kernel.org/tip/1a2cbc38b74f10c11837f88475d683c69c8503f6
Author: Jiri Bohac <[email protected]>
AuthorDate: Wed, 31 Jan 2024 01:04:28 +01:00
Committer: Dave Hansen <[email protected]>
CommitterDate: Fri, 01 Mar 2024 08:34:25 -08:00

x86/e820: Don't reserve SETUP_RNG_SEED in e820

SETUP_RNG_SEED in setup_data is supplied by kexec and should
not be reserved in the e820 map.

Doing so reserves 16 bytes of RAM when booting with kexec.
(16 bytes because data->len is zeroed by parse_setup_data so only
sizeof(setup_data) is reserved.)

When kexec is used repeatedly, each boot adds two entries in the
kexec-provided e820 map as the 16-byte range splits a larger
range of usable memory. Eventually all of the 128 available entries
get used up. The next split will result in losing usable memory
as the new entries cannot be added to the e820 map.

Fixes: 68b8e9713c8e ("x86/setup: Use rng seeds from setup_data")
Signed-off-by: Jiri Bohac <[email protected]>
Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Cc: <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/kernel/e820.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index fb8cf95..b66f540 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1017,10 +1017,12 @@ void __init e820__reserve_setup_data(void)
e820__range_update(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);

/*
- * SETUP_EFI and SETUP_IMA are supplied by kexec and do not need
- * to be reserved.
+ * SETUP_EFI, SETUP_IMA and SETUP_RNG_SEED are supplied by
+ * kexec and do not need to be reserved.
*/
- if (data->type != SETUP_EFI && data->type != SETUP_IMA)
+ if (data->type != SETUP_EFI &&
+ data->type != SETUP_IMA &&
+ data->type != SETUP_RNG_SEED)
e820__range_update_kexec(pa_data,
sizeof(*data) + data->len,
E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);

2024-03-01 18:37:29

by tip-bot2 for Jacob Pan

Subject: [tip: x86/urgent] x86/e820: Don't reserve SETUP_RNG_SEED in e820

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID: 7fd817c906503b6813ea3b41f5fdf4192449a707
Gitweb: https://git.kernel.org/tip/7fd817c906503b6813ea3b41f5fdf4192449a707
Author: Jiri Bohac <[email protected]>
AuthorDate: Wed, 31 Jan 2024 01:04:28 +01:00
Committer: Dave Hansen <[email protected]>
CommitterDate: Fri, 01 Mar 2024 10:27:20 -08:00

x86/e820: Don't reserve SETUP_RNG_SEED in e820

SETUP_RNG_SEED in setup_data is supplied by kexec and should
not be reserved in the e820 map.

Doing so reserves 16 bytes of RAM when booting with kexec.
(16 bytes because data->len is zeroed by parse_setup_data so only
sizeof(setup_data) is reserved.)

When kexec is used repeatedly, each boot adds two entries in the
kexec-provided e820 map as the 16-byte range splits a larger
range of usable memory. Eventually all of the 128 available entries
get used up. The next split will result in losing usable memory
as the new entries cannot be added to the e820 map.

Fixes: 68b8e9713c8e ("x86/setup: Use rng seeds from setup_data")
Signed-off-by: Jiri Bohac <[email protected]>
Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Signed-off-by: Dave Hansen <[email protected]>
Cc: <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/kernel/e820.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index fb8cf95..b66f540 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1017,10 +1017,12 @@ void __init e820__reserve_setup_data(void)
e820__range_update(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);

/*
- * SETUP_EFI and SETUP_IMA are supplied by kexec and do not need
- * to be reserved.
+ * SETUP_EFI, SETUP_IMA and SETUP_RNG_SEED are supplied by
+ * kexec and do not need to be reserved.
*/
- if (data->type != SETUP_EFI && data->type != SETUP_IMA)
+ if (data->type != SETUP_EFI &&
+ data->type != SETUP_IMA &&
+ data->type != SETUP_RNG_SEED)
e820__range_update_kexec(pa_data,
sizeof(*data) + data->len,
E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);