From: Stefano Stabellini <sstabellini@kernel.org>
To: Julien Grall <julien.grall@arm.com>
Cc: andre.przywara@arm.com, sstabellini@kernel.org,
steve.capper@arm.com, wei.chen@arm.com, xen-devel@lists.xen.org
Subject: Re: [RFC 15/16] xen/arm: traps: Don't inject a fault if the translation VA -> IPA fails
Date: Sat, 21 May 2016 15:42:30 +0100 (BST) [thread overview]
Message-ID: <alpine.DEB.2.10.1605211541530.2958@sstabellini-ThinkPad-X260> (raw)
In-Reply-To: <1462466065-30212-16-git-send-email-julien.grall@arm.com>
On Thu, 5 May 2016, Julien Grall wrote:
> Based on ARM ARM (D4.5.3 in ARM DDI 0486A and B3.12.7 in ARM DDI 0406C.c),
> a Stage 1 translation error has priority over a Stage 2 translation error.
>
> Therefore gva_to_ipa can only fail if another vCPU is playing with the
> page table.
>
> Rather than injecting a custom fault, replay the instruction and let the
> processor injecting the correct fault.
>
> Signed-off-by: Julien Grall <julien.grall@arm.com>
Couldn't a guest purposely cause a DoS in the hypervisor this way?
> xen/arch/arm/traps.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
> index c0325d5..3acdba0 100644
> --- a/xen/arch/arm/traps.c
> +++ b/xen/arch/arm/traps.c
> @@ -2410,7 +2410,7 @@ static void do_trap_instr_abort_guest(struct cpu_user_regs *regs,
>
> rc = gva_to_ipa(gva, &gpa, GV2M_READ);
> if ( rc == -EFAULT )
> - goto bad_insn_abort;
> + return; /* Try again */
> }
>
> rc = p2m_mem_access_check(gpa, gva, npfec);
> @@ -2422,7 +2422,6 @@ static void do_trap_instr_abort_guest(struct cpu_user_regs *regs,
> break;
> }
>
> -bad_insn_abort:
> inject_iabt_exception(regs, gva, hsr.len);
> }
>
> @@ -2452,7 +2451,7 @@ static void do_trap_data_abort_guest(struct cpu_user_regs *regs,
> {
> rc = gva_to_ipa(info.gva, &info.gpa, GV2M_READ);
> if ( rc == -EFAULT )
> - goto bad_data_abort;
> + return; /* Try again */
> }
>
> switch ( dabt.dfsc & 0x3f )
> --
> 1.9.1
>
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
next prev parent reply other threads:[~2016-05-21 14:42 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-05 16:34 [RFC 00/16] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
2016-05-05 16:34 ` [RFC 01/16] xen/arm: Makefile: Sort the entries alphabetically Julien Grall
2016-05-09 9:34 ` Stefano Stabellini
2016-05-05 16:34 ` [RFC 02/16] xen/arm: Include the header asm-arm/system.h in asm-arm/page.h Julien Grall
2016-05-09 9:34 ` Stefano Stabellini
2016-05-05 16:34 ` [RFC 03/16] xen/arm: Add macros to handle the MIDR Julien Grall
2016-05-09 9:37 ` Stefano Stabellini
2016-05-05 16:34 ` [RFC 04/16] xen/arm: arm64: Import flush_icache_range from Linux v4.6-rc3 Julien Grall
2016-05-09 9:40 ` Julien Grall
2016-05-05 16:34 ` [RFC 05/16] xen/arm: Add cpu_hwcap bitmap Julien Grall
2016-05-09 9:53 ` Stefano Stabellini
2016-05-09 10:02 ` Julien Grall
2016-05-05 16:34 ` [RFC 06/16] xen/arm64: Add an helper to invalidate all instruction caches Julien Grall
2016-05-09 9:50 ` Stefano Stabellini
2016-05-05 16:34 ` [RFC 07/16] xen/arm: arm64: Move the define BRK_BUG_FRAME into a separate header Julien Grall
2016-05-09 9:55 ` Stefano Stabellini
2016-05-05 16:34 ` [RFC 08/16] xen/arm: arm64: Reserve a brk immediate to fault on purpose Julien Grall
2016-05-09 9:58 ` Stefano Stabellini
2016-05-05 16:34 ` [RFC 09/16] xen/arm: arm64: Add helpers to decode and encode branch instructions Julien Grall
2016-05-09 10:05 ` Stefano Stabellini
2016-05-09 13:04 ` Julien Grall
2016-05-23 10:52 ` Julien Grall
2016-05-13 20:35 ` Konrad Rzeszutek Wilk
2016-05-14 10:49 ` Julien Grall
2016-05-05 16:34 ` [RFC 10/16] xen/arm: Introduce alternative runtime patching Julien Grall
2016-05-13 20:26 ` Konrad Rzeszutek Wilk
2016-05-14 18:02 ` Julien Grall
2016-05-21 15:09 ` Stefano Stabellini
2016-05-23 11:11 ` Julien Grall
2016-05-30 14:45 ` Stefano Stabellini
2016-05-30 16:42 ` Julien Grall
2016-05-31 9:21 ` Stefano Stabellini
2016-05-31 10:24 ` Julien Grall
2016-06-02 14:46 ` Konrad Rzeszutek Wilk
2016-06-02 15:04 ` Julien Grall
2016-06-02 15:14 ` Julien Grall
2016-06-06 14:17 ` Konrad Rzeszutek Wilk
2016-06-06 14:18 ` Julien Grall
2016-05-05 16:34 ` [RFC 11/16] xen/arm: Detect silicon revision and set cap bits accordingly Julien Grall
2016-05-13 20:37 ` Konrad Rzeszutek Wilk
2016-05-14 18:04 ` Julien Grall
2016-05-16 13:50 ` Konrad Rzeszutek Wilk
2016-05-16 13:54 ` Julien Grall
2016-05-05 16:34 ` [RFC 12/16] xen/arm: Document the errata implemented in Xen Julien Grall
2016-05-05 16:34 ` [RFC 13/16] xen/arm: arm64: Add Cortex-A53 cache errata workaround Julien Grall
2016-05-21 14:40 ` Stefano Stabellini
2016-05-23 13:39 ` Julien Grall
2016-05-05 16:34 ` [RFC 14/16] xen/arm: arm64: Add cortex-A57 erratum 832075 workaround Julien Grall
2016-05-05 16:34 ` [RFC 15/16] xen/arm: traps: Don't inject a fault if the translation VA -> IPA fails Julien Grall
2016-05-21 14:42 ` Stefano Stabellini [this message]
2016-05-21 14:51 ` Stefano Stabellini
2016-05-23 13:45 ` Julien Grall
2016-05-05 16:34 ` [RFC 16/16] xen/arm: arm64: Document Cortex-A57 erratum 834220 Julien Grall
2016-05-05 16:38 ` [RFC 00/16] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
2016-05-11 2:28 ` Wei Chen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=alpine.DEB.2.10.1605211541530.2958@sstabellini-ThinkPad-X260 \
--to=sstabellini@kernel.org \
--cc=andre.przywara@arm.com \
--cc=julien.grall@arm.com \
--cc=steve.capper@arm.com \
--cc=wei.chen@arm.com \
--cc=xen-devel@lists.xen.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).