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From: Avi Kivity <avi@redhat.com>
To: Carsten Otte <carsteno@de.ibm.com>
Cc: Alexander Graf <agraf@suse.de>,
	qemu-devel <qemu-devel@nongnu.org>,
	uli@suse.de, Carsten Otte <cotte@de.ibm.com>,
	hare@suse.de, KVM list <kvm@vger.kernel.org>
Subject: Re: [PATCH 0/9] S390x KVM support
Date: Thu, 22 Oct 2009 12:02:09 +0200	[thread overview]
Message-ID: <4AE02DA1.8090500@redhat.com> (raw)
In-Reply-To: <4AE02379.4090603@de.ibm.com>

On 10/22/2009 11:18 AM, Carsten Otte wrote:
>
>> I'd also appreciate an explanation of what this is all about.
> The processor status word does contain various bits about the CPU's 
> state, such as interrupt mask bits, current address space, and the 
> current instruction address. The status is kept in the in-kernel sie 
> control block data structure and has so far only been mirrored into 
> kvm_run during exit_reason == s390_sieic exits because user space 
> needs to work on it. It was never part of get_regs/set_regs and 
> friends as performance optimization: it's needed on almost every exit, 
> having it in kvm_run saves doing syscalls.
> The gdb stub requires an up-to-date copy at every exit, and therefore 
> the patch moves it out of the union and updates it at all userland exits.

gdb is hardly performance critical.  Is that the only reason for the change?

-- 
error compiling committee.c: too many arguments to function


  reply	other threads:[~2009-10-22 10:02 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1255963059-10298-1-git-send-email-agraf@suse.de>
     [not found] ` <4ADDE7E3.9090601@de.ibm.com>
2009-10-22  9:08   ` [PATCH 0/9] S390x KVM support Avi Kivity
2009-10-22  9:11     ` Alexander Graf
2009-10-22  9:53       ` Avi Kivity
2009-10-22  9:55         ` Alexander Graf
2009-10-22  9:58           ` Alexander Graf
2009-10-22 10:03           ` Avi Kivity
2009-10-22 10:13             ` Alexander Graf
2009-10-22 10:22             ` Carsten Otte
2009-10-22 10:28               ` Avi Kivity
2009-10-22 10:43                 ` Carsten Otte
2009-10-22 10:49                   ` Avi Kivity
2009-10-22 11:10                     ` Carsten Otte
2009-11-02 20:23                       ` Alexander Graf
2009-11-03  8:55                         ` Avi Kivity
2009-10-22  9:18     ` Carsten Otte
2009-10-22 10:02       ` Avi Kivity [this message]
2009-10-22 10:20         ` Carsten Otte
2009-10-22 10:29           ` Avi Kivity

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