From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Tamas K Lengyel <tamas@tklengyel.com>, Jan Beulich <JBeulich@suse.com>
Cc: Kevin Tian <kevin.tian@intel.com>, Wei Liu <wei.liu2@citrix.com>,
Razvan Cojocaru <rcojocaru@bitdefender.com>,
Ian Jackson <ian.jackson@eu.citrix.com>,
Jun Nakajima <jun.nakajima@intel.com>,
Xen-devel <xen-devel@lists.xenproject.org>
Subject: Re: [PATCH v4 8/8] x86/vm_event: Add HVM debug exception vm_events
Date: Mon, 30 May 2016 21:58:07 +0100 [thread overview]
Message-ID: <574CA95F.1030204@citrix.com> (raw)
In-Reply-To: <CABfawhmG7U6K8hg2r28DjQ+Z0AouPqA8rDY=OmrPGcHH2OPJYg@mail.gmail.com>
>>> @@ -3393,8 +3409,9 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
>>> }
>>> else {
>>> int handled =
>>> - hvm_monitor_breakpoint(regs->eip,
>>> - HVM_MONITOR_SOFTWARE_BREAKPOINT);
>>> + hvm_monitor_debug(regs->eip,
>>> + HVM_MONITOR_SOFTWARE_BREAKPOINT,
>>> + X86_EVENTTYPE_SW_EXCEPTION, 1);
>> Please let's not add further mistakes like this, assuming INT3 can't
>> have any prefixes. It can, even if they're useless.
> You mean the instruction length is not necessarily 1? Ultimately it
> doesn't seem to matter because reinjecting it with xc_hvm_inject_trap
> ignores this field. Instruction length is only required to be properly
> set AFAICT for a subset of debug exceptions during reinjection.
Almost all x86 instructions can have redundant prefixes which change
their length without altering their functionality.
This specific area was the subject of XSA-106, and is astoundingly fragile.
Luckily, I have an available functional test which confirms correct
behaviour from the point of view of the guest.
http://xenbits.xen.org/people/andrewcoop/xen-test-framework/test-swint-emulation.html
Please confirm that this test returns success even when being monitored
with this new functionality.
~Andrew
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next prev parent reply other threads:[~2016-05-30 20:58 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-29 22:37 [PATCH v4 1/8] monitor: Rename vm_event_monitor_get_capabilities Tamas K Lengyel
2016-05-29 22:37 ` [PATCH v4 2/8] monitor: Rename vm_event_monitor_guest_request Tamas K Lengyel
2016-05-30 7:05 ` Razvan Cojocaru
2016-05-30 13:51 ` Jan Beulich
2016-05-29 22:37 ` [PATCH v4 3/8] monitor: Rename hvm/event to hvm/monitor Tamas K Lengyel
2016-05-30 7:08 ` Razvan Cojocaru
2016-05-30 13:53 ` Jan Beulich
2016-05-29 22:37 ` [PATCH v4 4/8] monitor: ARM SMC events Tamas K Lengyel
2016-06-01 11:37 ` Julien Grall
[not found] ` <CABfawhmO9tUG3-OcorfwqdOgZTkjoUk+u=dHySGonBDvobqyKw@mail.gmail.com>
[not found] ` <CABfawhmK2GAmQqZMhrgjYzeUZ_XaoyRUPuJxyPK5LJEHwsp5SA@mail.gmail.com>
[not found] ` <CABfawh=J1fwinTYKGvJNrFPOsGLSXz6U3GE8fxPz3-KsXSWfbQ@mail.gmail.com>
[not found] ` <CABfawhn7zvE=hn0hq1ryH+sW-jdkAXgZM1C2KxwZVUE8pbp8cQ@mail.gmail.com>
2016-06-01 15:41 ` Tamas K Lengyel
2016-06-02 14:23 ` Julien Grall
2016-06-02 22:31 ` Tamas K Lengyel
2016-07-04 19:13 ` Tamas K Lengyel
2016-07-04 20:02 ` Julien Grall
2016-07-04 21:05 ` Tamas K Lengyel
2016-07-05 9:58 ` Julien Grall
2016-05-29 22:37 ` [PATCH v4 5/8] arm/vm_event: get/set registers Tamas K Lengyel
2016-05-30 7:09 ` Razvan Cojocaru
2016-05-30 11:50 ` Jan Beulich
2016-05-30 19:47 ` Tamas K Lengyel
2016-05-30 20:20 ` Julien Grall
2016-05-30 20:37 ` Tamas K Lengyel
2016-05-30 20:46 ` Razvan Cojocaru
2016-05-30 20:53 ` Tamas K Lengyel
2016-05-30 21:35 ` Julien Grall
2016-05-30 21:41 ` Tamas K Lengyel
2016-05-31 7:54 ` Jan Beulich
2016-05-31 8:06 ` Razvan Cojocaru
2016-05-31 8:30 ` Jan Beulich
2016-05-31 16:20 ` Tamas K Lengyel
2016-05-31 7:48 ` Jan Beulich
2016-05-31 16:28 ` Tamas K Lengyel
2016-06-01 8:41 ` Jan Beulich
2016-06-01 11:24 ` Julien Grall
2016-06-01 18:21 ` Tamas K Lengyel
2016-06-01 19:34 ` Razvan Cojocaru
2016-06-01 19:43 ` Julien Grall
2016-06-02 7:35 ` Jan Beulich
2016-06-02 8:26 ` Razvan Cojocaru
2016-06-02 9:38 ` Jan Beulich
2016-06-02 9:42 ` Razvan Cojocaru
2016-06-01 19:38 ` Julien Grall
2016-06-01 19:49 ` Julien Grall
2016-06-01 19:50 ` Tamas K Lengyel
2016-05-29 22:37 ` [PATCH v4 6/8] tools/libxc: add xc_monitor_privileged_call Tamas K Lengyel
2016-05-29 22:37 ` [PATCH v4 7/8] tools/xen-access: add test-case for ARM SMC Tamas K Lengyel
2016-05-30 9:56 ` Wei Liu
2016-05-29 22:37 ` [PATCH v4 8/8] x86/vm_event: Add HVM debug exception vm_events Tamas K Lengyel
2016-05-30 7:29 ` Razvan Cojocaru
2016-05-30 14:16 ` Jan Beulich
2016-05-30 20:13 ` Tamas K Lengyel
2016-05-30 20:58 ` Andrew Cooper [this message]
2016-05-31 7:59 ` Jan Beulich
2016-06-01 21:46 ` Tamas K Lengyel
2016-06-01 22:17 ` Andrew Cooper
2016-06-02 0:01 ` Tamas K Lengyel
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