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From: Paolo Bonzini <pbonzini@redhat.com>
To: Bandan Das <bsd@redhat.com>, Nadav Amit <namit@cs.technion.ac.il>
Cc: gleb@kernel.org, tglx@linutronix.de, mingo@redhat.com,
	hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org, joro@8bytes.org
Subject: Re: [PATCH 3/3] KVM: x86: correct mwait and monitor emulation
Date: Wed, 18 Jun 2014 18:44:34 +0200	[thread overview]
Message-ID: <53A1C1F2.4010909@redhat.com> (raw)
In-Reply-To: <jpg7g4ew4m6.fsf@redhat.com>

Il 18/06/2014 18:43, Bandan Das ha scritto:
>> > mwait and monitor are currently handled as nop. Considering this behavior, they
>> > should still be handled correctly, i.e., check execution conditions and generate
>> > exceptions when required. mwait and monitor may also be executed in real-mode
> Is this necessary ? They are NOPs and kvm prints that out (correctly so) to dmesg.
> Implementing them correctly is a different thing, but adding extra checks for NOPs
> just seems like adding extra cycles.

Raising the correct exception is a good thing, though.  The guest is 
going to busy wait anyway, it doesn't matter how fast it does that. :)

Paolo

  reply	other threads:[~2014-06-18 16:44 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-18 14:19 [PATCH 0/3] Correct monitor-mwait emulation as nop Nadav Amit
2014-06-18 14:19 ` [PATCH 1/3] KVM: x86: Emulator flag for instruction with no big real mode Nadav Amit
2014-06-18 14:19 ` [PATCH 2/3] KVM: x86: Emulator support for #UD on CPL>0 Nadav Amit
2014-06-18 16:29   ` Paolo Bonzini
2014-06-18 14:19 ` [PATCH 3/3] KVM: x86: correct mwait and monitor emulation Nadav Amit
2014-06-18 16:32   ` Paolo Bonzini
2014-06-18 16:43   ` Bandan Das
2014-06-18 16:44     ` Paolo Bonzini [this message]
2014-06-18 17:33       ` Bandan Das
2014-06-18 17:59   ` Eric Northup
2014-06-18 18:23     ` Nadav Amit
2014-06-18 18:30       ` Eric Northup
2014-06-18 18:59         ` Gabriel L. Somlo
2014-06-18 18:46     ` Gabriel L. Somlo
2014-06-18 19:09       ` Bandan Das
2014-06-19 10:18       ` Michael S. Tsirkin
     [not found]         ` <1B06E887-9D07-4E85-AE06-75B01787C488@gmail.com>
2014-06-19 11:23           ` Gleb Natapov
2014-06-19 11:52             ` Nadav Amit
2014-06-19 12:01               ` Michael S. Tsirkin
2014-06-19 12:07               ` Gleb Natapov
2014-06-19 12:10                 ` Nadav Amit
2014-06-19 12:16                   ` Gleb Natapov
2014-06-19 12:17                   ` Michael S. Tsirkin
2014-06-19 12:28                     ` Nadav Amit
2014-06-19 11:34     ` Paolo Bonzini

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