lkml.org 
[lkml]   [2019]   [Mar]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [PATCHv2] x86/boot/KASLR: skip the specified crashkernel reserved region
    On Thu, Mar 21, 2019 at 2:38 PM Chao Fan <fanc.fnst@cn.fujitsu.com> wrote:
    >
    > On Wed, Mar 13, 2019 at 12:19:31PM +0800, Pingfan Liu wrote:
    >
    > I tested it in Qemu test with 12G memory, and set crashkernel=6G@6G.
    > Without this PATCH, it successed to reserve memory just 4 times(total
    > 10 times).
    > With this PATCH, it successed to reserve memory 15 times(total 15
    > times).
    >
    > So I think if you post new version, you can add:
    >
    > Tested-by: Chao Fan <fanc.fnst@cn.fujitsu.com>
    >
    Appreciate for your testing. I had done some test on a real machine
    with a private patch to narrow down the KASLR range. I think your test
    method is more simple and I will add the tested-by you.

    Regards,
    Pingfan

    > Thanks,
    > Chao Fan
    >
    > >crashkernel=x@y option may fail to reserve the required memory region if
    > >KASLR puts kernel into the region. To avoid this uncertainty, making KASLR
    > >skip the required region.
    > >
    > >Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
    > >Cc: Thomas Gleixner <tglx@linutronix.de>
    > >Cc: Ingo Molnar <mingo@redhat.com>
    > >Cc: Borislav Petkov <bp@alien8.de>
    > >Cc: "H. Peter Anvin" <hpa@zytor.com>
    > >Cc: Baoquan He <bhe@redhat.com>
    > >Cc: Will Deacon <will.deacon@arm.com>
    > >Cc: Nicolas Pitre <nico@linaro.org>
    > >Cc: Pingfan Liu <kernelfans@gmail.com>
    > >Cc: Chao Fan <fanc.fnst@cn.fujitsu.com>
    > >Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
    > >Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
    > >Cc: linux-kernel@vger.kernel.org
    > >---
    > >v1 -> v2: fix some trival format
    > >
    > > arch/x86/boot/compressed/kaslr.c | 26 ++++++++++++++++++++++++--
    > > 1 file changed, 24 insertions(+), 2 deletions(-)
    > >
    > >diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
    > >index 9ed9709..e185318 100644
    > >--- a/arch/x86/boot/compressed/kaslr.c
    > >+++ b/arch/x86/boot/compressed/kaslr.c
    > >@@ -109,6 +109,7 @@ enum mem_avoid_index {
    > > MEM_AVOID_BOOTPARAMS,
    > > MEM_AVOID_MEMMAP_BEGIN,
    > > MEM_AVOID_MEMMAP_END = MEM_AVOID_MEMMAP_BEGIN + MAX_MEMMAP_REGIONS - 1,
    > >+ MEM_AVOID_CRASHKERNEL,
    > > MEM_AVOID_MAX,
    > > };
    > >
    > >@@ -240,6 +241,25 @@ static void parse_gb_huge_pages(char *param, char *val)
    > > }
    > > }
    > >
    > >+/* parse crashkernel=x@y option */
    > >+static void mem_avoid_crashkernel_simple(char *option)
    > >+{
    > >+ unsigned long long crash_size, crash_base;
    > >+ char *cur = option;
    > >+
    > >+ crash_size = memparse(option, &cur);
    > >+ if (option == cur)
    > >+ return;
    > >+
    > >+ if (*cur == '@') {
    > >+ option = cur + 1;
    > >+ crash_base = memparse(option, &cur);
    > >+ if (option == cur)
    > >+ return;
    > >+ mem_avoid[MEM_AVOID_CRASHKERNEL].start = crash_base;
    > >+ mem_avoid[MEM_AVOID_CRASHKERNEL].size = crash_size;
    > >+ }
    > >+}
    > >
    > > static void handle_mem_options(void)
    > > {
    > >@@ -250,7 +270,7 @@ static void handle_mem_options(void)
    > > u64 mem_size;
    > >
    > > if (!strstr(args, "memmap=") && !strstr(args, "mem=") &&
    > >- !strstr(args, "hugepages"))
    > >+ !strstr(args, "hugepages") && !strstr(args, "crashkernel="))
    > > return;
    > >
    > > tmp_cmdline = malloc(len + 1);
    > >@@ -286,6 +306,8 @@ static void handle_mem_options(void)
    > > goto out;
    > >
    > > mem_limit = mem_size;
    > >+ } else if (strstr(param, "crashkernel")) {
    > >+ mem_avoid_crashkernel_simple(val);
    > > }
    > > }
    > >
    > >@@ -414,7 +436,7 @@ static void mem_avoid_init(unsigned long input, unsigned long input_size,
    > >
    > > /* We don't need to set a mapping for setup_data. */
    > >
    > >- /* Mark the memmap regions we need to avoid */
    > >+ /* Mark the regions we need to avoid */
    > > handle_mem_options();
    > >
    > > #ifdef CONFIG_X86_VERBOSE_BOOTUP
    > >--
    > >2.7.4
    > >
    > >
    > >
    >
    >

    \
     
     \ /
      Last update: 2019-03-22 08:48    [W:2.286 / U:0.080 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site