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From: Paolo Bonzini <pbonzini@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
	Denys Vlasenko <dvlasenk@redhat.com>
Cc: "Andy Lutomirski" <luto@amacapital.net>,
	"Sara Sharon" <sara.sharon@intel.com>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Christian König" <christian.koenig@amd.com>,
	"Vinod Koul" <vinod.koul@intel.com>,
	"Alex Deucher" <alexander.deucher@amd.com>,
	"Johannes Berg" <johannes.berg@intel.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	"Andy Lutomirski" <luto@kernel.org>,
	"the arch/x86 maintainers" <x86@kernel.org>,
	"Ingo Molnar" <mingo@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"Adrian Hunter" <adrian.hunter@intel.com>
Subject: Re: RFC: Petition Intel/AMD to add POPF_IF insn
Date: Fri, 19 Aug 2016 12:54:39 +0200	[thread overview]
Message-ID: <f91d4c19-688b-ff13-8905-377c0f5cea77@redhat.com> (raw)
In-Reply-To: <CA+55aFxWeVBjZeDUS3-hLjG-CuzRYfxsrMaQxxG_KH02ttZ5Dg@mail.gmail.com>



On 18/08/2016 19:24, Linus Torvalds wrote:
>> > I didn't do CPL0 tests yet. Realized that cli/sti can be tested in userspace
>> > if we set iopl(3) first.
> Yes, but it might not be the same. So the timings could be very
> different from a cpl0 case.

FWIW I recently measured around 20 cycles for a popf as well on
Haswell-EP and CPL=0 (that was for commit f2485b3e0c6c, "KVM: x86: use
guest_exit_irqoff", 2016-07-01).

Paolo

  parent reply	other threads:[~2016-08-19 10:54 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-17 17:20 Denys Vlasenko
2016-08-17 17:30 ` Christian König
2016-08-17 18:34   ` Denys Vlasenko
2016-08-17 17:32 ` Linus Torvalds
2016-08-17 18:41   ` Denys Vlasenko
     [not found]     ` <CA+55aFwmxwQBkyDjombS4cy1q=a_buhmDjDnaa8rdC8ZDaDYEA@mail.gmail.com>
2016-08-17 19:13       ` Andy Lutomirski
2016-08-17 19:26         ` Denys Vlasenko
2016-08-17 19:32           ` Linus Torvalds
2016-08-17 19:35             ` Denys Vlasenko
2016-08-17 19:54               ` Linus Torvalds
2016-08-17 19:37             ` Linus Torvalds
2016-08-17 21:26               ` Linus Torvalds
2016-08-17 21:35                 ` Linus Torvalds
2016-08-17 21:43                   ` Andy Lutomirski
2016-08-17 21:48                     ` Linus Torvalds
2016-08-18 13:26                       ` Denys Vlasenko
2016-08-18 17:24                         ` Linus Torvalds
2016-08-18 17:47                           ` Denys Vlasenko
2016-08-18 17:49                             ` Denys Vlasenko
2016-08-19 10:54                           ` Paolo Bonzini [this message]
2016-08-31 11:12                             ` Denys Vlasenko
2016-08-18  9:21                   ` Denys Vlasenko
2016-08-18 12:18                     ` Denys Vlasenko
2016-08-18 17:22                       ` Paolo Bonzini
2016-08-17 19:29         ` Linus Torvalds

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