From: "Jan Beulich" <JBeulich@suse.com>
To: Konrad Rzeszutek Wilk <konrad@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
Keir Fraser <keir@xen.org>,
andrew.cooper3@citrix.com, mpohlack@amazon.de,
ross.lagerwall@citrix.com, Julien Grall <julien.grall@arm.com>,
sasha.levin@oracle.com, xen-devel@lists.xenproject.org
Subject: Re: [PATCH v9 11/27] xsplice: Implement payload loading
Date: Wed, 27 Apr 2016 10:06:17 -0600 [thread overview]
Message-ID: <5720FF9902000078000E672C@prv-mh.provo.novell.com> (raw)
In-Reply-To: <20160427154825.GD26384@x230.dumpdata.com>
>>> On 27.04.16 at 17:48, <konrad@kernel.org> wrote:
> Here is the inline patch:
At first I'll reply on just the particular issue in move_payload(); I'll
then go through the entire patch to see if anything else needs
commenting.
> +static int move_payload(struct payload *payload, struct xsplice_elf *elf)
> +{
> + void *text_buf, *ro_buf, *rw_buf;
> + unsigned int i;
> + size_t size = 0;
> + unsigned int *offset;
> + int rc = 0;
> +
> + offset = xmalloc_array(unsigned int, elf->hdr->e_shnum);
> + if ( !offset )
> + return -ENOMEM;
> +
> + /* Compute size of different regions. */
> + for ( i = 1; i < elf->hdr->e_shnum; i++ )
> + {
> + if ( (elf->sec[i].sec->sh_flags & SHF_ALLOC) &&
> + (elf->sec[i].sec->sh_flags & SHF_EXECINSTR) &&
> + !(elf->sec[i].sec->sh_flags & SHF_WRITE) )
> + calc_section(&elf->sec[i], &payload->text_size, &offset[i]);
> + else if ( (elf->sec[i].sec->sh_flags & SHF_ALLOC) &&
> + !(elf->sec[i].sec->sh_flags & SHF_EXECINSTR) &&
> + (elf->sec[i].sec->sh_flags & SHF_WRITE) )
> + calc_section(&elf->sec[i], &payload->rw_size, &offset[i]);
> + else if ( (elf->sec[i].sec->sh_flags & SHF_ALLOC) &&
> + !(elf->sec[i].sec->sh_flags & SHF_EXECINSTR) &&
> + !(elf->sec[i].sec->sh_flags & SHF_WRITE) )
> + calc_section(&elf->sec[i], &payload->ro_size, &offset[i]);
> + else if ( !elf->sec[i].sec->sh_flags ||
> + (elf->sec[i].sec->sh_flags & SHF_EXECINSTR) ||
> + (elf->sec[i].sec->sh_flags & SHF_MASKPROC) )
> + /*
> + * Do nothing. These are .rel.text, rel.*, .symtab, .strtab,
> + * and .shstrtab. For the non-relocate we allocate and copy these
> + * via other means - and the .rel we can ignore as we only use it
> + * once during loading.
> + */
> + offset[i] = UINT_MAX;
> + else if ( (elf->sec[i].sec->sh_flags & SHF_ALLOC) &&
> + (elf->sec[i].sec->sh_type == SHT_NOBITS) )
> + {
> + dprintk(XENLOG_DEBUG, XSPLICE "%s: Not supporting %s section!\n",
> + elf->name, elf->sec[i].name);
> + rc = -EOPNOTSUPP;
> + goto out;
> + }
> + else /* Such as .comment, or .debug_str. */
> + {
> + dprintk(XENLOG_DEBUG, XSPLICE "%s: Ignoring %s section!\n",
> + elf->name, elf->sec[i].name);
> + offset[i] = UINT_MAX;
> + }
I continue to not understand why SHT_NOBITS, SHF_MASKPROC, or
zero sh_flags need considering here at all. You really only care about
SHF_ALLOC sections here (as I think you confirmed on irc), so why
can't you just start this whole sequence with
if ( !(elf->sec[i].sec->sh_flags & SHF_ALLOC) )
<ignore-this-section>
then handle RX, RW, and RO just like you do now and finally have
an "else" covering unsupported SHF_ALLOC sections. Less code,
and easier to understand.
Jan
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next prev parent reply other threads:[~2016-04-27 16:06 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-25 15:34 [PATCH 9] xSplice v1 design and implementation Konrad Rzeszutek Wilk
2016-04-25 15:34 ` [PATCH v9 01/27] Revert "libxc/libxl/python/xenstat/ocaml: Use new XEN_VERSION hypercall" Konrad Rzeszutek Wilk
2016-04-25 15:48 ` Jan Beulich
2016-04-25 15:53 ` Wei Liu
2016-04-25 15:34 ` [PATCH v9 02/27] Revert "HYPERCALL_version_op. New hypercall mirroring XENVER_ but sane." Konrad Rzeszutek Wilk
2016-04-25 15:34 ` [PATCH v9 03/27] xsplice: Design document Konrad Rzeszutek Wilk
2016-04-25 15:34 ` [PATCH v9 04/27] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op Konrad Rzeszutek Wilk
2016-04-26 7:48 ` Ross Lagerwall
2016-04-26 7:52 ` Ross Lagerwall
2016-04-26 10:21 ` Jan Beulich
2016-04-26 17:50 ` Konrad Rzeszutek Wilk
2016-04-27 6:51 ` Jan Beulich
2016-04-27 13:47 ` Konrad Rzeszutek Wilk
2016-04-27 14:11 ` Jan Beulich
2016-04-25 15:34 ` [PATCH v9 05/27] libxc: Implementation of XEN_XSPLICE_op in libxc Konrad Rzeszutek Wilk
2016-04-26 7:51 ` Ross Lagerwall
2016-04-25 15:34 ` [PATCH v9 06/27] xen-xsplice: Tool to manipulate xsplice payloads Konrad Rzeszutek Wilk
2016-04-26 7:49 ` Ross Lagerwall
2016-04-25 15:34 ` [PATCH v9 07/27] arm/x86: Use struct virtual_region to do bug, symbol, and (x86) exception tables lookup Konrad Rzeszutek Wilk
2016-04-26 10:31 ` Jan Beulich
2016-04-25 15:34 ` [PATCH v9 08/27] arm/x86/vmap: Add v[z|m]alloc_xen and vm_init_type Konrad Rzeszutek Wilk
2016-04-26 10:47 ` Jan Beulich
2016-04-27 2:38 ` Konrad Rzeszutek Wilk
2016-04-27 7:12 ` Jan Beulich
2016-04-27 13:46 ` Konrad Rzeszutek Wilk
2016-04-27 14:15 ` Jan Beulich
2016-04-25 15:34 ` [PATCH v9 09/27] x86/mm: Introduce modify_xen_mappings() Konrad Rzeszutek Wilk
2016-04-25 15:34 ` [PATCH v9 10/27] xsplice: Add helper elf routines Konrad Rzeszutek Wilk
2016-04-26 10:05 ` Ross Lagerwall
2016-04-26 11:52 ` Jan Beulich
2016-04-26 12:37 ` Jan Beulich
2016-04-27 1:59 ` Konrad Rzeszutek Wilk
2016-04-27 7:27 ` Jan Beulich
2016-04-27 14:00 ` Konrad Rzeszutek Wilk
2016-04-27 4:06 ` Konrad Rzeszutek Wilk
2016-04-27 7:52 ` Jan Beulich
2016-04-27 18:45 ` Konrad Rzeszutek Wilk
2016-04-25 15:34 ` [PATCH v9 11/27] xsplice: Implement payload loading Konrad Rzeszutek Wilk
2016-04-26 10:48 ` Ross Lagerwall
2016-04-26 13:39 ` Jan Beulich
2016-04-27 1:47 ` Konrad Rzeszutek Wilk
2016-04-27 7:57 ` Jan Beulich
2016-04-27 3:28 ` Konrad Rzeszutek Wilk
2016-04-27 8:28 ` Jan Beulich
2016-04-27 15:48 ` Konrad Rzeszutek Wilk
2016-04-27 16:06 ` Jan Beulich [this message]
2016-04-27 16:14 ` Jan Beulich
2016-04-27 18:40 ` Konrad Rzeszutek Wilk
2016-04-25 15:34 ` [PATCH v9 12/27] xsplice: Implement support for applying/reverting/replacing patches Konrad Rzeszutek Wilk
2016-04-26 15:21 ` Jan Beulich
2016-04-27 3:39 ` Konrad Rzeszutek Wilk
2016-04-27 8:36 ` Jan Beulich
2016-05-11 9:51 ` Martin Pohlack
2016-05-11 13:56 ` Konrad Rzeszutek Wilk
2016-04-25 15:35 ` [PATCH v9 13/27] x86/xen_hello_world.xsplice: Test payload for patching 'xen_extra_version' Konrad Rzeszutek Wilk
2016-04-26 15:31 ` Jan Beulich
2016-04-25 15:35 ` [PATCH v9 14/27] xsplice, symbols: Implement symbol name resolution on address Konrad Rzeszutek Wilk
2016-04-26 15:48 ` Jan Beulich
2016-04-25 15:35 ` [PATCH v9 15/27] xsplice, symbols: Implement fast symbol names -> virtual addresses lookup Konrad Rzeszutek Wilk
2016-04-26 15:53 ` Jan Beulich
2016-04-25 15:35 ` [PATCH v9 16/27] x86, xsplice: Print payload's symbol name and payload name in backtraces Konrad Rzeszutek Wilk
2016-04-26 11:06 ` Ross Lagerwall
2016-04-26 12:41 ` Jan Beulich
2016-04-26 12:48 ` Ross Lagerwall
2016-04-26 13:41 ` Jan Beulich
2016-04-27 3:31 ` Konrad Rzeszutek Wilk
2016-04-27 8:37 ` Jan Beulich
2016-04-25 15:35 ` [PATCH v9 17/27] xsplice: Add support for bug frames Konrad Rzeszutek Wilk
2016-04-26 11:05 ` Ross Lagerwall
2016-04-26 13:08 ` Ross Lagerwall
2016-04-26 15:58 ` Jan Beulich
2016-04-25 15:35 ` [PATCH v9 18/27] xsplice: Add support for exception tables Konrad Rzeszutek Wilk
2016-04-26 16:01 ` Jan Beulich
2016-04-25 15:35 ` [PATCH v9 19/27] xsplice: Add support for alternatives Konrad Rzeszutek Wilk
2016-04-27 8:58 ` Jan Beulich
2016-04-25 15:35 ` [PATCH v9 20/27] build_id: Provide ld-embedded build-ids Konrad Rzeszutek Wilk
2016-04-25 15:35 ` [PATCH v9 21/27] xsplice: Print build_id in keyhandler and on bootup Konrad Rzeszutek Wilk
2016-04-25 15:35 ` [PATCH v9 22/27] XENVER_build_id/libxc: Provide ld-embedded build-id Konrad Rzeszutek Wilk
2016-04-25 15:35 ` [PATCH v9 23/27] libxl: info: Display build_id of the hypervisor Konrad Rzeszutek Wilk
2016-04-25 15:35 ` [PATCH v9 24/27] xsplice: Stacking build-id dependency checking Konrad Rzeszutek Wilk
2016-04-27 9:27 ` Jan Beulich
2016-04-27 16:36 ` Konrad Rzeszutek Wilk
2016-04-28 9:47 ` Jan Beulich
2016-04-25 15:35 ` [PATCH v9 25/27] xsplice/xen_replace_world: Test-case for XSPLICE_ACTION_REPLACE Konrad Rzeszutek Wilk
2016-04-25 15:35 ` [PATCH v9 26/27] xsplice: Prevent duplicate payloads from being loaded Konrad Rzeszutek Wilk
2016-04-27 9:31 ` Jan Beulich
2016-04-25 15:35 ` [PATCH v9 27/27] MAINTAINERS/xsplice: Add myself and Ross as the maintainers Konrad Rzeszutek Wilk
2016-04-25 15:41 ` [PATCH 9] xSplice v1 design and implementation Jan Beulich
2016-04-25 15:47 ` Konrad Rzeszutek Wilk
2016-04-25 15:54 ` Jan Beulich
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