From: Borislav Petkov <bp@alien8.de>
To: Mike Rapoport <rppt@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Baoquan He <bhe@redhat.com>, David Hildenbrand <david@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Mel Gorman <mgorman@suse.de>, Michal Hocko <mhocko@kernel.org>,
Mike Rapoport <rppt@linux.ibm.com>, Qian Cai <cai@lca.pw>,
Thomas Gleixner <tglx@linutronix.de>,
Vlastimil Babka <vbabka@suse.cz>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org
Subject: Re: [PATCH 2/2] x86/setup: merge several reservations of start of the memory
Date: Mon, 25 Jan 2021 15:55:58 +0100 [thread overview]
Message-ID: <20210125145558.GE23070@zn.tnic> (raw)
In-Reply-To: <20210115083255.12744-3-rppt@kernel.org>
On Fri, Jan 15, 2021 at 10:32:55AM +0200, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@linux.ibm.com>
>
> Currently the first several pages are reserved both to avoid leaking their
> contents on systems with L1TF and to avoid corrupting BIOS memory.
>
> Merge the two memory reservations.
>
> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
> ---
> arch/x86/kernel/setup.c | 29 +++++++++++------------------
> 1 file changed, 11 insertions(+), 18 deletions(-)
>
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 32cd2e790a0a..3f2fd67240f8 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -715,20 +715,6 @@ static int __init parse_reservelow(char *p)
>
> early_param("reservelow", parse_reservelow);
>
> -static void __init trim_low_memory_range(void)
> -{
> - /*
> - * A special case is the first 4Kb of memory;
> - * This is a BIOS owned area, not kernel ram, but generally
> - * not listed as such in the E820 table.
> - *
> - * This typically reserves additional memory (64KiB by default)
> - * since some BIOSes are known to corrupt low memory. See the
> - * Kconfig help text for X86_RESERVE_LOW.
> - */
> - memblock_reserve(0, ALIGN(reserve_low, PAGE_SIZE));
> -}
> -
> static void __init early_reserve_memory(void)
> {
> /*
> @@ -741,10 +727,18 @@ static void __init early_reserve_memory(void)
> (unsigned long)__end_of_kernel_reserve - (unsigned long)_text);
>
> /*
> - * Make sure page 0 is always reserved because on systems with
> - * L1TF its contents can be leaked to user processes.
> + * The first 4Kb of memory is a BIOS owned area, but generally it is
> + * not listed as such in the E820 table.
> + *
> + * Reserve the first memory page and typically some additional
> + * memory (64KiB by default) since some BIOSes are known to corrupt
> + * low memory. See the Kconfig help text for X86_RESERVE_LOW.
> + *
> + * In addition, we must make sure page 0 is always reserved because
s/we must//
Other than that:
Reviewed-by: Borislav Petkov <bp@suse.de>
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2021-01-25 14:56 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-15 8:32 [PATCH 0/2] x86/setup: consolidate early memory reservations Mike Rapoport
2021-01-15 8:32 ` [PATCH 1/2] " Mike Rapoport
2021-01-15 10:10 ` David Hildenbrand
2021-01-25 14:50 ` Borislav Petkov
2021-01-25 15:31 ` Mike Rapoport
2021-01-25 16:56 ` Borislav Petkov
2021-01-25 14:59 ` Borislav Petkov
2021-01-25 15:33 ` Mike Rapoport
2021-01-15 8:32 ` [PATCH 2/2] x86/setup: merge several reservations of start of the memory Mike Rapoport
2021-01-15 10:09 ` David Hildenbrand
2021-01-25 14:55 ` Borislav Petkov [this message]
2021-01-15 11:42 ` [PATCH 0/2] x86/setup: consolidate early memory reservations Baoquan He
2021-01-15 11:56 ` Baoquan He
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