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From: "Pavel Dovgalyuk" <dovgaluk@ispras.ru>
To: "'Peter Xu'" <peterx@redhat.com>
Cc: ehabkost@redhat.com, quintela@redhat.com, dgilbert@redhat.com,
	qemu-devel@nongnu.org, pbonzini@redhat.com, rth@twiddle.net
Subject: Re: [Qemu-devel] i386: EFER vs 32-bit CPU
Date: Thu, 30 May 2019 08:54:38 +0300	[thread overview]
Message-ID: <000901d516ac$2b1a7d80$814f7880$@ru> (raw)
In-Reply-To: <20190530005243.GA28587@xz-x1>

> From: Peter Xu [mailto:peterx@redhat.com]
> On Wed, May 29, 2019 at 02:26:39PM +0300, Pavel Dovgalyuk wrote:
> > Hello!
> >
> >
> >
> > I found this while debugging the inconsistent saved/restored state of the virtual machine.
> >
> >
> >
> > i386 (32 bit) emulation uses this register (in wrmsr and in MMU fault processing).
> 
> Sorry if this question is elementary, but... why would a 32bit guest
> use IA32_EFER?  From SDM I only see 4 bits defined in this MSR (SCE,
> LME, LMA, NXE) but is there any of them that should be set in a 32bit
> guest?

Ubuntu server 16.04 (32 bit) sets NXE while booting.
NXE affects the MMU fault processing and exception generation.

Pavel Dovgalyuk



  reply	other threads:[~2019-05-30  5:55 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-29 11:26 [Qemu-devel] i386: EFER vs 32-bit CPU Pavel Dovgalyuk
2019-05-29 11:30 ` Dr. David Alan Gilbert
2019-05-29 11:39   ` Paolo Bonzini
2019-05-29 11:53     ` Pavel Dovgalyuk
2019-05-29 12:36       ` Dr. David Alan Gilbert
2019-05-29 14:03         ` Pavel Dovgalyuk
2019-05-30  0:52 ` Peter Xu
2019-05-30  5:54   ` Pavel Dovgalyuk [this message]
2019-05-30  9:00     ` Peter Xu
2019-05-30  9:04       ` Peter Xu
2019-05-30 11:00 ` TeLeMan

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