From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org,
Stefano Stabellini <Stefano.Stabellini@eu.citrix.com>
Subject: Re: [PATCH v6 00/27] x86, boot, 64bit: Add support for loading ramdisk and bzImage above 4G
Date: Fri, 21 Dec 2012 17:38:24 -0500 [thread overview]
Message-ID: <20121221223824.GC1102@phenom.dumpdata.com> (raw)
In-Reply-To: <50CA6918.5060806@zytor.com>
On Thu, Dec 13, 2012 at 03:47:36PM -0800, H. Peter Anvin wrote:
> There are obviously good bits to this patchset, but I'm really
> starting to think the "pseudo-linear mode" via a trap handler --
> meaning we can access all of memory without any extra effort --
> makes more sense. In fact, that way we could just build the full
> page tables without worrying about incremental bootstrap, depending
> on if that is a complexity win or not.
>
> Either way, this is for native only: the Xen domain builder or other
> similar entry paths should be setting up page tables that cover all
> of memory; I'm hoping Konrad and Stefano can confirm this.
We do setup __ka space for everything everything we need to a fault.
Prior to 3.5 we could have blown over to the MODULES_SPACE if the guest
was booted with more than 128GB. That is now fixed so most of the
space _after_ the ramdisk in the __ka space can be blown away
and we use __va. We do this "cleanup" in xen_pagetable_init stage.
Which works as a long as cleanup_highmap only cleans up to
max_pfn_mapped (which in Xen case covers up to the RAMdisk).
The layout of __ka space is as follow:
kernel
ramdisk
an array called P2M for which we use __ka address until xen_pagetable_init
at which point we blow away any __ka entries for it.
start_info (we swap over to use __va before generic code is run).
the initial page-tables (for which the kernel uses __va address). we blow
away the __ka entries when xen_pagetable_init is called.
This __ka cleanup business was done for 64-bit only as the 32-bit
code scared me.
Hm, why that function is called xen_pagetable_init seems a bit silly.
>
> The only reason to go with another approach I can think of is if it
> makes 32/64-bit unification cleaner.
>
> -hpa
>
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prev parent reply other threads:[~2012-12-21 22:38 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-13 22:01 [PATCH v6 00/27] x86, boot, 64bit: Add support for loading ramdisk and bzImage above 4G Yinghai Lu
2012-12-13 22:01 ` [PATCH v6 01/27] x86, mm: Fix page table early allocation offset checking Yinghai Lu
2012-12-14 10:53 ` Borislav Petkov
2012-12-19 3:30 ` Yinghai Lu
2012-12-19 17:16 ` Borislav Petkov
2012-12-13 22:01 ` [PATCH v6 02/27] x86, mm: make pgd next calculation consistent with pud/pmd Yinghai Lu
2012-12-14 14:34 ` Borislav Petkov
2012-12-19 3:37 ` Yinghai Lu
2012-12-19 20:48 ` Borislav Petkov
2012-12-19 21:55 ` Yinghai Lu
2012-12-13 22:01 ` [PATCH v6 03/27] x86, boot: move verify_cpu.S and no_longmode after 0x200 Yinghai Lu
2012-12-15 17:06 ` Borislav Petkov
2012-12-19 3:44 ` Yinghai Lu
2012-12-19 20:57 ` Borislav Petkov
2012-12-19 21:58 ` Yinghai Lu
2012-12-19 22:04 ` Borislav Petkov
2012-12-22 2:24 ` Konrad Rzeszutek Wilk
2012-12-13 22:01 ` [PATCH v6 04/27] x86, boot: Move lldt/ltr out of 64bit code section Yinghai Lu
2012-12-15 17:28 ` Borislav Petkov
2012-12-19 3:53 ` Yinghai Lu
2012-12-13 22:01 ` [PATCH v6 05/27] x86, 64bit: clear ident mapping when kernel is above 512G Yinghai Lu
2012-12-16 17:49 ` Borislav Petkov
2012-12-16 18:04 ` Yinghai Lu
2012-12-19 3:57 ` Yinghai Lu
2012-12-13 22:02 ` [PATCH v6 06/27] x86, 64bit: Set extra ident mapping for whole kernel range Yinghai Lu
2012-12-13 22:02 ` [PATCH v6 07/27] x86: Merge early_reserve_initrd for 32bit and 64bit Yinghai Lu
2012-12-13 22:02 ` [PATCH v6 08/27] x86: add get_ramdisk_image/size() Yinghai Lu
2012-12-13 22:02 ` [PATCH v6 09/27] x86, boot: add get_cmd_line_ptr() Yinghai Lu
2012-12-13 22:02 ` [PATCH v6 10/27] x86, boot: move checking of cmd_line_ptr out of common path Yinghai Lu
2012-12-13 22:02 ` [PATCH v6 11/27] x86, boot: update cmd_line_ptr to unsigned long Yinghai Lu
2012-12-13 22:02 ` [PATCH v6 12/27] x86: use io_remap to access real_mode_data Yinghai Lu
2012-12-13 22:02 ` [PATCH v6 13/27] x86: use rsi/rdi to pass realmode_data pointer Yinghai Lu
2012-12-13 22:02 ` [PATCH v6 14/27] x86, kexec: remove 1024G limitation for kexec buffer on 64bit Yinghai Lu
2012-12-13 22:02 ` [PATCH v6 15/27] x86, kexec: set ident mapping for kernel that is above max_pfn Yinghai Lu
2012-12-13 22:02 ` [PATCH v6 16/27] x86, kexec: Merge ident_mapping_init and init_level4_page Yinghai Lu
2012-12-13 22:02 ` [PATCH v6 17/27] x86, kexec: only set ident mapping for ram Yinghai Lu
2012-12-13 22:02 ` [PATCH v6 18/27] x86, boot: add fields to support load bzImage and ramdisk above 4G Yinghai Lu
2012-12-13 22:54 ` H. Peter Anvin
2012-12-13 23:28 ` Yinghai Lu
2012-12-13 23:38 ` H. Peter Anvin
2012-12-13 22:02 ` [PATCH v6 19/27] x86, boot: update comments about entries for 64bit image Yinghai Lu
2012-12-13 23:27 ` H. Peter Anvin
2012-12-14 0:13 ` Yinghai Lu
2012-12-14 0:38 ` H. Peter Anvin
2012-12-14 0:44 ` Yinghai Lu
2012-12-14 0:51 ` H. Peter Anvin
2012-12-14 0:51 ` Yinghai Lu
2012-12-14 0:54 ` H. Peter Anvin
2012-12-14 1:00 ` Yinghai Lu
2012-12-14 1:04 ` H. Peter Anvin
2012-12-14 2:15 ` Yinghai Lu
2012-12-13 22:02 ` [PATCH v6 20/27] x86, 64bit: Print init kernel lowmap correctly Yinghai Lu
2012-12-13 22:02 ` [PATCH v6 21/27] x86, boot: Not need to check setup_header version Yinghai Lu
2012-12-13 22:02 ` [PATCH v6 22/27] mm: Add alloc_bootmem_low_pages_nopanic() Yinghai Lu
2012-12-13 22:02 ` [PATCH v6 23/27] x86: Don't panic if can not alloc buffer for swiotlb Yinghai Lu
2012-12-22 2:21 ` Konrad Rzeszutek Wilk
2012-12-13 22:02 ` [PATCH v6 24/27] x86: Add swiotlb force off support Yinghai Lu
2012-12-22 2:18 ` Konrad Rzeszutek Wilk
2012-12-22 5:00 ` Yinghai Lu
2012-12-23 5:00 ` H. Peter Anvin
2012-12-13 22:02 ` [PATCH v6 25/27] x86, kdump: remove crashkernel range find limit for 64bit Yinghai Lu
2012-12-13 22:02 ` [PATCH v6 26/27] x86: add Crash kernel low reservation Yinghai Lu
2012-12-13 22:02 ` [PATCH v6 27/27] x86: Merge early kernel reserve for 32bit and 64bit Yinghai Lu
2012-12-13 23:47 ` [PATCH v6 00/27] x86, boot, 64bit: Add support for loading ramdisk and bzImage above 4G H. Peter Anvin
2012-12-14 0:00 ` Yinghai Lu
2012-12-21 22:38 ` Konrad Rzeszutek Wilk [this message]
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