From: Kyle Huey <me@kylehuey.com>
To: xen-devel@lists.xen.org
Cc: Robert O'Callahan <robert@ocallahan.org>
Subject: [PATCH v2] x86/Intel: virtualize support for cpuid faulting
Date: Thu, 13 Oct 2016 14:09:25 -0700 [thread overview]
Message-ID: <20161013210927.4629-1-khuey@kylehuey.com> (raw)
rr (http://rr-project.org/), a Linux userspace record-and-replay reverse-
execution debugger, would like to trap and emulate the CPUID instruction.
This would allow us to a) mask away certain hardware features that rr does
not support (e.g. RDRAND) and b) enable trace portability across machines
by providing constant results. Patches for support in the Linux kernel are in
flight, and we'd like to be able to use this feature on virtualized Linux
instances as well.
Changes since the previous version:
- Rebased.
- Exposed cpuid_faulting_enabled outside of cpu/intel.c, as suggested by
Andrew Cooper. This is now patch 1, and the original changes are in
patch 2.
- Various style nits from Andrew Cooper and Jan Beulich.
- Additional style changes not suggested (primarily replacing ternaries with
if (condition) value |= BIT for futureproofing).
- Check guest_kernel_mode instead of ring_0 in emulate_privileged_op.
- Check cpuid_fault and guest_kernel_mode in emulate_forced_invalid_op.
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next reply other threads:[~2016-10-13 21:09 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-13 21:09 Kyle Huey [this message]
2016-10-13 21:09 ` [PATCH v2 1/2] x86/Intel: Expose cpuid_faulting_enabled so it can be used elsewhere Kyle Huey
2016-10-14 11:51 ` Jan Beulich
2016-10-13 21:09 ` [PATCH v2 2/2] x86/Intel: virtualize support for cpuid faulting Kyle Huey
2016-10-14 12:04 ` Jan Beulich
2016-10-14 14:46 ` Andrew Cooper
2016-10-14 17:05 ` Kyle Huey
2016-10-14 17:18 ` Andrew Cooper
2016-10-14 19:28 ` Kyle Huey
2016-10-17 9:23 ` Andrew Cooper
2016-10-14 19:36 ` Kyle Huey
2016-10-17 12:34 ` Andrew Cooper
2016-10-17 16:28 ` Kyle Huey
2016-10-17 16:39 ` Andrew Cooper
2016-10-17 17:42 ` Kyle Huey
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