[Linux-stable-mirror] [PATCH 4.9 v2] x86/pti/efi: broken conversion from efi to kernel page table
The page table order must be increased for EFI table in order to avoid a bug where NMI tries to change the page table to kernel page table, while efi page table is active.
For more disccussion about this bug, see this thread: http://lkml.iu.edu/hypermail/linux/kernel/1801.1/00951.html
Signed-off-by: Pavel Tatashin pasha.tatashin@oracle.com Reviewed-by: Steven Sistare steven.sistare@oracle.com Acked-by: Jiri Kosina jkosina@suse.cz --- arch/x86/include/asm/pgalloc.h | 11 +++++++++++ arch/x86/mm/pgtable.c | 7 ------- arch/x86/platform/efi/efi_64.c | 2 +- 3 files changed, 12 insertions(+), 8 deletions(-)
Changelog: v1 - v2: Fixed compiling warning
diff --git a/arch/x86/include/asm/pgalloc.h b/arch/x86/include/asm/pgalloc.h index b6d425999f99..1178a51b77f3 100644 --- a/arch/x86/include/asm/pgalloc.h +++ b/arch/x86/include/asm/pgalloc.h @@ -27,6 +27,17 @@ static inline void paravirt_release_pud(unsigned long pfn) {} */ extern gfp_t __userpte_alloc_gfp;
+#ifdef CONFIG_PAGE_TABLE_ISOLATION +/* + * Instead of one PGD, we acquire two PGDs. Being order-1, it is + * both 8k in size and 8k-aligned. That lets us just flip bit 12 + * in a pointer to swap between the two 4k halves. + */ +#define PGD_ALLOCATION_ORDER 1 +#else +#define PGD_ALLOCATION_ORDER 0 +#endif + /* * Allocate and free page tables. */ diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index 5aaec8effc5f..209b9465e97a 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -345,13 +345,6 @@ static inline void _pgd_free(pgd_t *pgd) } #else
-/* - * Instead of one pgd, Kaiser acquires two pgds. Being order-1, it is - * both 8k in size and 8k-aligned. That lets us just flip bit 12 - * in a pointer to swap between the two 4k halves. - */ -#define PGD_ALLOCATION_ORDER kaiser_enabled - static inline pgd_t *_pgd_alloc(void) { return (pgd_t *)__get_free_pages(PGALLOC_GFP, PGD_ALLOCATION_ORDER); diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index 2f25a363068c..dcb2d9d185a2 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -142,7 +142,7 @@ int __init efi_alloc_page_tables(void) return 0;
gfp_mask = GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO; - efi_pgd = (pgd_t *)__get_free_page(gfp_mask); + efi_pgd = (pgd_t *)__get_free_pages(gfp_mask, PGD_ALLOCATION_ORDER); if (!efi_pgd) return -ENOMEM;
This is a note to let you know that I've just added the patch titled
x86/pti/efi: broken conversion from efi to kernel page table
to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: x86-pti-efi-broken-conversion-from-efi-to-kernel-page-table.patch and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From pasha.tatashin@oracle.com Mon Jan 15 18:48:49 2018
From: Pavel Tatashin pasha.tatashin@oracle.com Date: Mon, 15 Jan 2018 11:44:14 -0500 Subject: x86/pti/efi: broken conversion from efi to kernel page table To: steven.sistare@oracle.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, gregkh@linuxfoundation.org, jkosina@suse.cz, hughd@google.com, dave.hansen@linux.intel.com, luto@kernel.org, stable@vger.kernel.org Message-ID: 20180115164414.19778-1-pasha.tatashin@oracle.com
From: Pavel Tatashin pasha.tatashin@oracle.com
The page table order must be increased for EFI table in order to avoid a bug where NMI tries to change the page table to kernel page table, while efi page table is active.
For more disccussion about this bug, see this thread: http://lkml.iu.edu/hypermail/linux/kernel/1801.1/00951.html
Signed-off-by: Pavel Tatashin pasha.tatashin@oracle.com Reviewed-by: Steven Sistare steven.sistare@oracle.com Acked-by: Jiri Kosina jkosina@suse.cz Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/include/asm/pgalloc.h | 11 +++++++++++ arch/x86/mm/pgtable.c | 7 ------- arch/x86/platform/efi/efi_64.c | 2 +- 3 files changed, 12 insertions(+), 8 deletions(-)
Changelog: v1 - v2: Fixed compiling warning
--- a/arch/x86/include/asm/pgalloc.h +++ b/arch/x86/include/asm/pgalloc.h @@ -27,6 +27,17 @@ static inline void paravirt_release_pud( */ extern gfp_t __userpte_alloc_gfp;
+#ifdef CONFIG_PAGE_TABLE_ISOLATION +/* + * Instead of one PGD, we acquire two PGDs. Being order-1, it is + * both 8k in size and 8k-aligned. That lets us just flip bit 12 + * in a pointer to swap between the two 4k halves. + */ +#define PGD_ALLOCATION_ORDER 1 +#else +#define PGD_ALLOCATION_ORDER 0 +#endif + /* * Allocate and free page tables. */ --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -345,13 +345,6 @@ static inline void _pgd_free(pgd_t *pgd) } #else
-/* - * Instead of one pgd, Kaiser acquires two pgds. Being order-1, it is - * both 8k in size and 8k-aligned. That lets us just flip bit 12 - * in a pointer to swap between the two 4k halves. - */ -#define PGD_ALLOCATION_ORDER kaiser_enabled - static inline pgd_t *_pgd_alloc(void) { return (pgd_t *)__get_free_pages(PGALLOC_GFP, PGD_ALLOCATION_ORDER); --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -142,7 +142,7 @@ int __init efi_alloc_page_tables(void) return 0;
gfp_mask = GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO; - efi_pgd = (pgd_t *)__get_free_page(gfp_mask); + efi_pgd = (pgd_t *)__get_free_pages(gfp_mask, PGD_ALLOCATION_ORDER); if (!efi_pgd) return -ENOMEM;
Patches currently in stable-queue which might be from pasha.tatashin@oracle.com are
queue-4.9/x86-pti-efi-broken-conversion-from-efi-to-kernel-page-table.patch
On Mon, Jan 15, 2018 at 11:44:14AM -0500, Pavel Tatashin wrote:
The page table order must be increased for EFI table in order to avoid a bug where NMI tries to change the page table to kernel page table, while efi page table is active.
For more disccussion about this bug, see this thread: http://lkml.iu.edu/hypermail/linux/kernel/1801.1/00951.html
Signed-off-by: Pavel Tatashin pasha.tatashin@oracle.com Reviewed-by: Steven Sistare steven.sistare@oracle.com Acked-by: Jiri Kosina jkosina@suse.cz
arch/x86/include/asm/pgalloc.h | 11 +++++++++++ arch/x86/mm/pgtable.c | 7 ------- arch/x86/platform/efi/efi_64.c | 2 +- 3 files changed, 12 insertions(+), 8 deletions(-)
Changelog: v1 - v2: Fixed compiling warning
Many thanks for this, now queued up.
greg k-h
linux-stable-mirror@lists.linaro.org
-
Greg KH -
gregkh＠linuxfoundation.org
-
Pavel Tatashin