From: Mike Rapoport <rppt@kernel.org>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Dan Williams <dan.j.williams@intel.com>,
Tony Luck <tony.luck@intel.com>,
x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Dave Hansen <dave.hansen@intel.com>,
stable@vger.kernel.org
Subject: Re: [PATCHv2 2/2] x86/boot/KASLR: Fix boot with some memory above MAXMEM
Date: Wed, 10 Jun 2020 11:42:23 +0300 [thread overview]
Message-ID: <20200610084223.GE1151302@kernel.org> (raw)
In-Reply-To: <20200608125424.70198-3-kirill.shutemov@linux.intel.com>
On Mon, Jun 08, 2020 at 03:54:24PM +0300, Kirill A. Shutemov wrote:
> A 5-level paging capable machine can have memory above 46-bit in the
> physical address space. This memory is only addressable in the 5-level
> paging mode: we don't have enough virtual address space to create direct
> mapping for such memory in the 4-level paging mode
>
> Teach KASLR to avoid memory regions above MAXMEM or truncate the region
> if the end is above MAXMEM.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Reviewed-by: Dave Hansen <dave.hansen@intel.com>
> Cc: stable@vger.kernel.org # v4.14
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
> ---
> arch/x86/boot/compressed/kaslr.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
> index d7408af55738..99db18eeb40e 100644
> --- a/arch/x86/boot/compressed/kaslr.c
> +++ b/arch/x86/boot/compressed/kaslr.c
> @@ -695,7 +695,18 @@ static bool process_mem_region(struct mem_vector *region,
> unsigned long long minimum,
> unsigned long long image_size)
> {
> + unsigned long long end;
> int i;
> +
> + /* Cannot access memory region above MAXMEM: skip it. */
> + if (region->start >= MAXMEM)
> + return 0;
> +
> + /* Truncate the region if the end is above MAXMEM */
> + end = region->start + region->size;
> + end = min_t(unsigned long long, end, MAXMEM - 1);
> + region->size = end - region->start;
> +
> /*
> * If no immovable memory found, or MEMORY_HOTREMOVE disabled,
> * use @region directly.
> --
> 2.26.2
>
>
--
Sincerely yours,
Mike.
prev parent reply other threads:[~2020-06-10 8:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-08 12:54 [PATCHv2 0/2] x86: Fix boot with some memory above MAXMEM Kirill A. Shutemov
2020-06-08 12:54 ` [PATCHv2 1/2] x86/mm: " Kirill A. Shutemov
2020-06-10 8:41 ` Mike Rapoport
2020-06-11 2:17 ` [x86/mm] c7b2a6d1af: kernel_BUG_at_arch/x86/mm/physaddr.c kernel test robot
2020-06-08 12:54 ` [PATCHv2 2/2] x86/boot/KASLR: Fix boot with some memory above MAXMEM Kirill A. Shutemov
2020-06-10 8:42 ` Mike Rapoport [this message]
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