Date: Tue, 27 May 2014 15:06:25 -0400 From: John Baldwin <jhb@freebsd.org> To: src-committers@freebsd.org Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org Subject: Re: svn commit: r266765 - in head/sys/amd64/vmm: . intel Message-ID: <201405271506.25140.jhb@freebsd.org> In-Reply-To: <201405271904.s4RJ4cx4068774@svn.freebsd.org> References: <201405271904.s4RJ4cx4068774@svn.freebsd.org>
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On Tuesday, May 27, 2014 3:04:38 pm John Baldwin wrote: > Author: jhb > Date: Tue May 27 19:04:38 2014 > New Revision: 266765 > URL: http://svnweb.freebsd.org/changeset/base/266765 > > Log: > - Rework the XSAVE/XRSTOR emulation to only expose XCR0 features to the > guest for which the rules regarding xsetbv emulation are known. In > particular future extensions like AVX-512 have interdependencies among > feature bits that could allow a guest to trigger a GP# in the host with > the current approach of allowing anything the host supports. > - Add proper checking of Intel MPX and AVX-512 XSAVE features in the > xsetbv emulation and allow these features to be exposed to the guest if > they are enabled in the host. > - Expose a subset of known-safe features from leaf 0 of the structured > extended features to guests if they are supported on the host including > RDFSBASE/RDGSBASE, BMI1/2, AVX2, AVX-512, HLE, ERMS, and RTM. Aside > from AVX-512, these features are all new instructions available for use > in ring 3 with no additional hypervisor changes needed. > > Reviewed by: neel Unfortunately there is no production silicon with either AVX-512 or MPX that runs FreeBSD AFAIK, so I haven't been able to test that this works correctly for those features. Using plain AVX in a guest still works ok though. -- John Baldwin
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