From: "Nadav Har'El" <nyh@math.technion.ac.il>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: "Roedel, Joerg" <Joerg.Roedel@amd.com>,
john cooper <john.cooper@redhat.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
Anthony Liguori <aliguori@us.ibm.com>, kvm <kvm@vger.kernel.org>
Subject: Re: drop -enable-nesting
Date: Mon, 30 May 2011 18:16:23 +0300 [thread overview]
Message-ID: <20110530151623.GA3630@fermat.math.technion.ac.il> (raw)
In-Reply-To: <4DE3B1E2.7020006@siemens.com>
On Mon, May 30, 2011, Jan Kiszka wrote about "Re: drop -enable-nesting":
> > "-enable-nesting" could remain as a synonym for enabling either VMX or SVM
> > in the guest, depending on what was available in the host (because KVM now
> > supports both nested SVM and nested VMX, but not SVM-on-VMX or vice versa).
>
> Why? Once nesting is stable (I think SVM already is), there is no reason
> for an explicit enable. And you can always mask it out via -cpu.
As far as I understand (and this was previously discussed on the QEMU mailing
list), the default emulated CPU does not include the "vmx" capability, and you
need to enable it with something like "-cpu qemu64,+vmx" (or "-cpu host").
I am not sure if it does enable the "svm" capability. If it does, it isn't
useful when KVM is enabled and the underlying host has VMX, not SVM.
Nadav.
--
Nadav Har'El | Monday, May 30 2011, 27 Iyyar 5771
nyh@math.technion.ac.il |-----------------------------------------
Phone +972-523-790466, ICQ 13349191 |Why do we drive on a parkway and park on
http://nadav.harel.org.il |a driveway?
WARNING: multiple messages have this Message-ID (diff)
From: "Nadav Har'El" <nyh@math.technion.ac.il>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: john cooper <john.cooper@redhat.com>,
"Roedel, Joerg" <Joerg.Roedel@amd.com>,
Anthony Liguori <aliguori@us.ibm.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
kvm <kvm@vger.kernel.org>
Subject: Re: [Qemu-devel] drop -enable-nesting
Date: Mon, 30 May 2011 18:16:23 +0300 [thread overview]
Message-ID: <20110530151623.GA3630@fermat.math.technion.ac.il> (raw)
In-Reply-To: <4DE3B1E2.7020006@siemens.com>
On Mon, May 30, 2011, Jan Kiszka wrote about "Re: drop -enable-nesting":
> > "-enable-nesting" could remain as a synonym for enabling either VMX or SVM
> > in the guest, depending on what was available in the host (because KVM now
> > supports both nested SVM and nested VMX, but not SVM-on-VMX or vice versa).
>
> Why? Once nesting is stable (I think SVM already is), there is no reason
> for an explicit enable. And you can always mask it out via -cpu.
As far as I understand (and this was previously discussed on the QEMU mailing
list), the default emulated CPU does not include the "vmx" capability, and you
need to enable it with something like "-cpu qemu64,+vmx" (or "-cpu host").
I am not sure if it does enable the "svm" capability. If it does, it isn't
useful when KVM is enabled and the underlying host has VMX, not SVM.
Nadav.
--
Nadav Har'El | Monday, May 30 2011, 27 Iyyar 5771
nyh@math.technion.ac.il |-----------------------------------------
Phone +972-523-790466, ICQ 13349191 |Why do we drive on a parkway and park on
http://nadav.harel.org.il |a driveway?
next prev parent reply other threads:[~2011-05-30 15:16 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-23 21:46 [Qemu-devel] [PATCH 3/7] cpu model bug fixes and definition corrections: Add kvm emulated x2apic flag to config defined cpu models john cooper
2011-05-28 8:39 ` Jan Kiszka
2011-05-30 8:18 ` Roedel, Joerg
2011-05-30 14:04 ` drop -enable-nesting (was: [PATCH 3/7] cpu model bug fixes and definition corrections...) Jan Kiszka
2011-05-30 14:04 ` [Qemu-devel] " Jan Kiszka
2011-05-30 14:38 ` Nadav Har'El
2011-05-30 14:38 ` [Qemu-devel] " Nadav Har'El
2011-05-30 15:04 ` drop -enable-nesting Jan Kiszka
2011-05-30 15:04 ` [Qemu-devel] " Jan Kiszka
2011-05-30 15:10 ` Roedel, Joerg
2011-05-30 15:10 ` [Qemu-devel] " Roedel, Joerg
2011-05-30 15:15 ` Jan Kiszka
2011-05-30 15:15 ` [Qemu-devel] " Jan Kiszka
2011-05-30 15:19 ` Avi Kivity
2011-05-30 15:19 ` [Qemu-devel] " Avi Kivity
2011-05-30 15:27 ` Jan Kiszka
2011-05-30 15:27 ` [Qemu-devel] " Jan Kiszka
2011-05-30 15:42 ` Jan Kiszka
2011-05-30 15:42 ` [Qemu-devel] " Jan Kiszka
2011-05-31 8:44 ` Daniel P. Berrange
2011-05-31 8:44 ` [Qemu-devel] " Daniel P. Berrange
2011-05-31 8:58 ` Avi Kivity
2011-05-31 8:58 ` [Qemu-devel] " Avi Kivity
2011-05-31 9:06 ` Roedel, Joerg
2011-05-31 9:06 ` [Qemu-devel] " Roedel, Joerg
2011-05-31 9:15 ` Paolo Bonzini
2011-05-31 9:15 ` [Qemu-devel] " Paolo Bonzini
2011-05-31 9:16 ` Avi Kivity
2011-05-31 9:16 ` [Qemu-devel] " Avi Kivity
2011-05-30 15:16 ` Nadav Har'El [this message]
2011-05-30 15:16 ` Nadav Har'El
2011-05-30 15:59 ` Jan Kiszka
2011-05-30 15:59 ` [Qemu-devel] " Jan Kiszka
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20110530151623.GA3630@fermat.math.technion.ac.il \
--to=nyh@math.technion.ac.il \
--cc=Joerg.Roedel@amd.com \
--cc=aliguori@us.ibm.com \
--cc=jan.kiszka@siemens.com \
--cc=john.cooper@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=qemu-devel@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.