* Re: [PATCH RESEND] x86/boot: Fix off-by-one error in sme_clear_pgd()
2026-09-18 14:27 [PATCH RESEND] x86/boot: Fix off-by-one error in sme_clear_pgd() Thorsten Blum
@ 2026-10-31 1:46 ` Andrew Morton
2026-11-04 20:14 ` Thorsten Blum
2026-11-05 14:12 ` Tom Lendacky
` (2 subsequent siblings)
3 siblings, 1 reply; 6+ messages in thread
From: Andrew Morton @ 2026-10-31 1:46 UTC (permalink / raw)
To: Thorsten Blum
Cc: Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, x86,
H. Peter Anvin, Ahmed S. Darwish, Kevin Brodsky, Andreas Larsson,
Yeoreum Yun, Tom Lendacky, Ritesh Harjani (IBM), Ingo Molnar,
linux-kernel
On Fri, 18 Sep 2026 16:27:13 +0200 Thorsten Blum <blum@kernel.org> wrote:
> The mapping helpers __sme_map_range_pmd() and __sme_map_range_pte(), and
> therefore sme_encrypt_kernel(), use exclusive end addresses and stop
> before vaddr reaches vaddr_end.
>
> However, sme_clear_pgd() treats vaddr_end as inclusive when calculating
> the last PGD entry to clear. If vaddr_end is PGD-aligned, the first PGD
> entry outside the range is cleared too.
>
> Use vaddr_end - 1 to calculate the last PGD entry within the range.
When fixing a bug, please always fully describe the worst-case
userspace-visible runtime effects of that bug.
I'm guessing "none known, this is from code inspection"?
Thanks.
> --- a/arch/x86/boot/startup/sme.c
> +++ b/arch/x86/boot/startup/sme.c
> @@ -99,7 +99,7 @@ static void __init sme_clear_pgd(struct sme_populate_pgd_data *ppd)
> pgd_t *pgd_p;
>
> pgd_start = ppd->vaddr & PGDIR_MASK;
> - pgd_end = ppd->vaddr_end & PGDIR_MASK;
> + pgd_end = (ppd->vaddr_end - 1) & PGDIR_MASK;
>
> pgd_size = (((pgd_end - pgd_start) / PGDIR_SIZE) + 1) * sizeof(pgd_t);
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH RESEND] x86/boot: Fix off-by-one error in sme_clear_pgd()
2026-10-31 1:46 ` Andrew Morton
@ 2026-11-04 20:14 ` Thorsten Blum
0 siblings, 0 replies; 6+ messages in thread
From: Thorsten Blum @ 2026-11-04 20:14 UTC (permalink / raw)
To: Andrew Morton
Cc: Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, x86,
H. Peter Anvin, Ahmed S. Darwish, Kevin Brodsky, Andreas Larsson,
Yeoreum Yun, Tom Lendacky, Ritesh Harjani (IBM), Ingo Molnar,
linux-kernel
On Fri, Oct 30, 2026 at 06:46:42PM -0700, Andrew Morton wrote:
> On Fri, 18 Sep 2026 16:27:13 +0200 Thorsten Blum <blum@kernel.org> wrote:
>
> > The mapping helpers __sme_map_range_pmd() and __sme_map_range_pte(), and
> > therefore sme_encrypt_kernel(), use exclusive end addresses and stop
> > before vaddr reaches vaddr_end.
> >
> > However, sme_clear_pgd() treats vaddr_end as inclusive when calculating
> > the last PGD entry to clear. If vaddr_end is PGD-aligned, the first PGD
> > entry outside the range is cleared too.
> >
> > Use vaddr_end - 1 to calculate the last PGD entry within the range.
>
> When fixing a bug, please always fully describe the worst-case
> userspace-visible runtime effects of that bug.
>
> I'm guessing "none known, this is from code inspection"?
Correct, this was found by code inspection.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH RESEND] x86/boot: Fix off-by-one error in sme_clear_pgd()
2026-09-18 14:27 [PATCH RESEND] x86/boot: Fix off-by-one error in sme_clear_pgd() Thorsten Blum
2026-10-31 1:46 ` Andrew Morton
@ 2026-11-05 14:12 ` Tom Lendacky
2026-11-05 19:07 ` [tip: x86/boot] " tip-bot2 for Thorsten Blum
2026-11-06 17:15 ` [tip: x86/urgent] " tip-bot2 for Thorsten Blum
3 siblings, 0 replies; 6+ messages in thread
From: Tom Lendacky @ 2026-11-05 14:12 UTC (permalink / raw)
To: Thorsten Blum, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
Dave Hansen, x86, H. Peter Anvin, Ahmed S. Darwish, Kevin Brodsky,
Andreas Larsson, Yeoreum Yun
Cc: Andrew Morton, Ritesh Harjani (IBM), Ingo Molnar, linux-kernel
On 9/18/26 09:27, Thorsten Blum wrote:
> The mapping helpers __sme_map_range_pmd() and __sme_map_range_pte(), and
> therefore sme_encrypt_kernel(), use exclusive end addresses and stop
> before vaddr reaches vaddr_end.
>
> However, sme_clear_pgd() treats vaddr_end as inclusive when calculating
> the last PGD entry to clear. If vaddr_end is PGD-aligned, the first PGD
> entry outside the range is cleared too.
>
> Use vaddr_end - 1 to calculate the last PGD entry within the range.
>
> Fixes: 6ebcb060713f ("x86/mm: Add support to encrypt the kernel in-place")
> Signed-off-by: Thorsten Blum <blum@kernel.org>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
> arch/x86/boot/startup/sme.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/boot/startup/sme.c b/arch/x86/boot/startup/sme.c
> index c07a2c381ed1..2d5cb3f7eee6 100644
> --- a/arch/x86/boot/startup/sme.c
> +++ b/arch/x86/boot/startup/sme.c
> @@ -99,7 +99,7 @@ static void __init sme_clear_pgd(struct sme_populate_pgd_data *ppd)
> pgd_t *pgd_p;
>
> pgd_start = ppd->vaddr & PGDIR_MASK;
> - pgd_end = ppd->vaddr_end & PGDIR_MASK;
> + pgd_end = (ppd->vaddr_end - 1) & PGDIR_MASK;
>
> pgd_size = (((pgd_end - pgd_start) / PGDIR_SIZE) + 1) * sizeof(pgd_t);
>
^ permalink raw reply [flat|nested] 6+ messages in thread* [tip: x86/boot] x86/boot: Fix off-by-one error in sme_clear_pgd()
2026-09-18 14:27 [PATCH RESEND] x86/boot: Fix off-by-one error in sme_clear_pgd() Thorsten Blum
2026-10-31 1:46 ` Andrew Morton
2026-11-05 14:12 ` Tom Lendacky
@ 2026-11-05 19:07 ` tip-bot2 for Thorsten Blum
2026-11-06 17:15 ` [tip: x86/urgent] " tip-bot2 for Thorsten Blum
3 siblings, 0 replies; 6+ messages in thread
From: tip-bot2 for Thorsten Blum @ 2026-11-05 19:07 UTC (permalink / raw)
To: linux-tip-commits
Cc: Thorsten Blum, Borislav Petkov (AMD), Tom Lendacky, x86,
linux-kernel
The following commit has been merged into the x86/boot branch of tip:
Commit-ID: 8523d938dce836fbe7ea33fcc98d8460b094ef81
Gitweb: https://git.kernel.org/tip/8523d938dce836fbe7ea33fcc98d8460b094ef81
Author: Thorsten Blum <blum@kernel.org>
AuthorDate: Fri, 18 Sep 2026 16:27:13 +02:00
Committer: Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Thu, 05 Nov 2026 10:21:38 -08:00
x86/boot: Fix off-by-one error in sme_clear_pgd()
The mapping helpers __sme_map_range_pmd() and __sme_map_range_pte(), and
therefore sme_encrypt_kernel(), use exclusive end addresses and stop
before vaddr reaches vaddr_end.
However, sme_clear_pgd() treats vaddr_end as inclusive when calculating
the last PGD entry to clear. If vaddr_end is PGD-aligned, the first PGD
entry outside the range is cleared too.
Use vaddr_end - 1 to calculate the last PGD entry within the range.
Fixes: 6ebcb060713f ("x86/mm: Add support to encrypt the kernel in-place")
Signed-off-by: Thorsten Blum <blum@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://patch.msgid.link/20260918142714.242711-2-blum@kernel.org
---
arch/x86/boot/startup/sme.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/boot/startup/sme.c b/arch/x86/boot/startup/sme.c
index c07a2c3..2d5cb3f 100644
--- a/arch/x86/boot/startup/sme.c
+++ b/arch/x86/boot/startup/sme.c
@@ -99,7 +99,7 @@ static void __init sme_clear_pgd(struct sme_populate_pgd_data *ppd)
pgd_t *pgd_p;
pgd_start = ppd->vaddr & PGDIR_MASK;
- pgd_end = ppd->vaddr_end & PGDIR_MASK;
+ pgd_end = (ppd->vaddr_end - 1) & PGDIR_MASK;
pgd_size = (((pgd_end - pgd_start) / PGDIR_SIZE) + 1) * sizeof(pgd_t);
^ permalink raw reply related [flat|nested] 6+ messages in thread* [tip: x86/urgent] x86/boot: Fix off-by-one error in sme_clear_pgd()
2026-09-18 14:27 [PATCH RESEND] x86/boot: Fix off-by-one error in sme_clear_pgd() Thorsten Blum
` (2 preceding siblings ...)
2026-11-05 19:07 ` [tip: x86/boot] " tip-bot2 for Thorsten Blum
@ 2026-11-06 17:15 ` tip-bot2 for Thorsten Blum
3 siblings, 0 replies; 6+ messages in thread
From: tip-bot2 for Thorsten Blum @ 2026-11-06 17:15 UTC (permalink / raw)
To: linux-tip-commits
Cc: Thorsten Blum, Borislav Petkov (AMD), Tom Lendacky, stable, x86,
linux-kernel
The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: cb319926808b1cca522d2087a13205e840beb45b
Gitweb: https://git.kernel.org/tip/cb319926808b1cca522d2087a13205e840beb45b
Author: Thorsten Blum <blum@kernel.org>
AuthorDate: Fri, 18 Sep 2026 16:27:13 +02:00
Committer: Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Fri, 06 Nov 2026 09:05:23 -08:00
x86/boot: Fix off-by-one error in sme_clear_pgd()
The mapping helpers __sme_map_range_pmd() and __sme_map_range_pte(), and
therefore sme_encrypt_kernel(), use exclusive end addresses and stop
before vaddr reaches vaddr_end.
However, sme_clear_pgd() treats vaddr_end as inclusive when calculating
the last PGD entry to clear. If vaddr_end is PGD-aligned, the first PGD
entry outside the range is cleared too.
Use vaddr_end - 1 to calculate the last PGD entry within the range.
Fixes: 6ebcb060713f ("x86/mm: Add support to encrypt the kernel in-place")
Signed-off-by: Thorsten Blum <blum@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260918142714.242711-2-blum@kernel.org
---
arch/x86/boot/startup/sme.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/boot/startup/sme.c b/arch/x86/boot/startup/sme.c
index c07a2c3..2d5cb3f 100644
--- a/arch/x86/boot/startup/sme.c
+++ b/arch/x86/boot/startup/sme.c
@@ -99,7 +99,7 @@ static void __init sme_clear_pgd(struct sme_populate_pgd_data *ppd)
pgd_t *pgd_p;
pgd_start = ppd->vaddr & PGDIR_MASK;
- pgd_end = ppd->vaddr_end & PGDIR_MASK;
+ pgd_end = (ppd->vaddr_end - 1) & PGDIR_MASK;
pgd_size = (((pgd_end - pgd_start) / PGDIR_SIZE) + 1) * sizeof(pgd_t);
^ permalink raw reply related [flat|nested] 6+ messages in thread