From: Borislav Petkov <bp@alien8.de>
To: Chao Fan <fanc.fnst@cn.fujitsu.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
linux-efi@vger.kernel.org, linux-acpi@vger.kernel.org,
tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com,
keescook@chromium.org, bhe@redhat.com, msys.mizuma@gmail.com,
indou.takao@jp.fujitsu.com, caoj.fnst@cn.fujitsu.com
Subject: Re: [PATCH v11 5/5] x86/boot/KASLR: Walk srat tables to filter immovable memory
Date: Fri, 16 Nov 2018 14:50:39 +0100 [thread overview]
Message-ID: <20181116135039.GE20313@zn.tnic> (raw)
In-Reply-To: <20181112094645.4879-6-fanc.fnst@cn.fujitsu.com>
Subject: Re: [PATCH v11 5/5] x86/boot/KASLR: Walk srat tables to filter immovable memory
s/srat/SRAT/g
On Mon, Nov 12, 2018 at 05:46:45PM +0800, Chao Fan wrote:
> KASLR may randomly chooses some positions which are located in movable
choose
> memory regions. This will break memory hotplug feature and make the
> movable memory chosen by KASLR can't be removed.
by KASLR practically immovable.
:)
> The solution is limite KASLR to choose memory regions in immovable
limite?
"to limit"
> node according to SRAT tables.
>
> If CONFIG_MEMORY_HOTREMOVE enabled, walk through the SRAT memory
*is* enabled,
> tables and store those immovable memory regions so that KASLR can get
> where to choose for randomization.
>
> If the amount of immovable memory regions is not zero, which
> means the immovable memory regions existing. Calculate the intersection
> between memory regions from e820/efi memory table and immovable memory
> regions.
This is explaining *what* the patch does and generally doesn't need to
be in the commit messge as people can read it in the patch itself.
> Signed-off-by: Chao Fan <fanc.fnst@cn.fujitsu.com>
> ---
> arch/x86/boot/compressed/kaslr.c | 77 +++++++++++++++++++++++++++-----
> 1 file changed, 66 insertions(+), 11 deletions(-)
>
> diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
> index b251572e77af..174d2114045e 100644
> --- a/arch/x86/boot/compressed/kaslr.c
> +++ b/arch/x86/boot/compressed/kaslr.c
> @@ -97,6 +97,11 @@ static bool memmap_too_large;
> /* Store memory limit specified by "mem=nn[KMG]" or "memmap=nn[KMG]" */
> static unsigned long long mem_limit = ULLONG_MAX;
>
> +#ifdef CONFIG_MEMORY_HOTREMOVE
> +/* Store the immovable memory regions */
> +extern struct mem_vector immovable_mem[MAX_NUMNODES*2];
> +#endif
For this and the other occurrences of ifdef CONFIG_MEMORY_HOTREMOVE,
define empty stubs for those functions in a header and remove the
ifdeffery at the call sites.
> +
>
> enum mem_avoid_index {
> MEM_AVOID_ZO_RANGE = 0,
> @@ -413,6 +418,11 @@ static void mem_avoid_init(unsigned long input, unsigned long input_size,
> /* Mark the memmap regions we need to avoid */
> handle_mem_options();
>
> +#ifdef CONFIG_MEMORY_HOTREMOVE
> + /* Mark the immovable regions we need to choose */
> + get_immovable_mem();
> +#endif
> +
> #ifdef CONFIG_X86_VERBOSE_BOOTUP
> /* Make sure video RAM can be used. */
> add_identity_map(0, PMD_SIZE);
> @@ -568,9 +578,9 @@ static unsigned long slots_fetch_random(void)
> return 0;
> }
>
> -static void process_mem_region(struct mem_vector *entry,
> - unsigned long minimum,
> - unsigned long image_size)
> +static void slots_count(struct mem_vector *entry,
That's a strange rename.
__process_mem_region() makes more sense to me.
> + unsigned long minimum,
> + unsigned long image_size)
> {
> struct mem_vector region, overlap;
> unsigned long start_orig, end;
> @@ -646,6 +656,57 @@ static void process_mem_region(struct mem_vector *entry,
> }
> }
>
> +static bool process_mem_region(struct mem_vector *region,
> + unsigned long long minimum,
> + unsigned long long image_size)
> +{
> + int i;
> + /*
> + * If no immovable memory found, or MEMORY_HOTREMOVE disabled,
> + * walk all the regions, so use region directely.
"directly"
> + */
> + if (num_immovable_mem == 0) {
if (!...
> + slots_count(region, minimum, image_size);
> +
> + if (slot_area_index == MAX_SLOT_AREA) {
> + debug_putstr("Aborted e820/efi memmap scan (slot_areas full)!\n");
> + return 1;
> + }
> + return 0;
> + }
> +
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
next prev parent reply other threads:[~2018-11-16 13:50 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-12 9:46 [PATCH v11 0/5] x86/boot/KASLR: Parse ACPI table and limit kaslr in immovable memory Chao Fan
2018-11-12 9:46 ` [PATCH v11 1/5] x86/boot: Add efi_get_rsdp_addr() to dig out RSDP from EFI table Chao Fan
2018-11-12 14:54 ` Borislav Petkov
2018-11-13 1:57 ` Chao Fan
2018-11-12 9:46 ` [PATCH v11 2/5] x86/boot: Add bios_get_rsdp_addr() to search RSDP in memory Chao Fan
2018-11-12 15:27 ` Borislav Petkov
2018-11-13 2:10 ` Chao Fan
2018-11-13 10:09 ` Borislav Petkov
2018-11-12 9:46 ` [PATCH v11 3/5] x86/boot: Add get_acpi_rsdp() to parse RSDP in cmdlien from kexec Chao Fan
2018-11-12 9:50 ` Chao Fan
2018-11-12 17:43 ` Masayoshi Mizuma
2018-11-13 2:12 ` Chao Fan
2018-11-13 16:11 ` Masayoshi Mizuma
2018-11-13 17:22 ` Borislav Petkov
2018-11-13 17:54 ` Borislav Petkov
2018-11-13 20:06 ` Masayoshi Mizuma
2018-11-13 21:51 ` Borislav Petkov
2018-11-14 6:12 ` Chao Fan
2018-11-14 18:30 ` Borislav Petkov
2018-11-19 1:16 ` Chao Fan
2018-11-13 17:51 ` Borislav Petkov
2018-11-14 1:54 ` Chao Fan
2018-11-14 1:59 ` Chao Fan
2018-11-14 18:33 ` Borislav Petkov
2018-11-12 9:46 ` [PATCH v11 4/5] x86/boot: Dig out SRAT table from RSDP and find immovable memory Chao Fan
2018-11-12 20:52 ` Masayoshi Mizuma
2018-11-13 2:43 ` Chao Fan
2018-11-12 21:51 ` Masayoshi Mizuma
2018-11-13 2:45 ` Chao Fan
2018-11-16 11:16 ` Borislav Petkov
2018-11-19 2:08 ` Chao Fan
2018-11-20 6:18 ` Chao Fan
2018-11-12 9:46 ` [PATCH v11 5/5] x86/boot/KASLR: Walk srat tables to filter " Chao Fan
2018-11-16 13:50 ` Borislav Petkov [this message]
2018-11-19 1:31 ` Chao Fan
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