From: "Nadav Har'El" <nyh@math.technion.ac.il>
To: Avi Kivity <avi@redhat.com>
Cc: kvm@vger.kernel.org, gleb@redhat.com
Subject: Re: [PATCH 15/27] nVMX: Prepare vmcs02 from vmcs01 and vmcs12
Date: Tue, 8 Feb 2011 14:13:15 +0200 [thread overview]
Message-ID: <20110208121315.GA28897@fermat.math.technion.ac.il> (raw)
In-Reply-To: <4CBB037A.2050906@redhat.com>
On Sun, Oct 17, 2010, Avi Kivity wrote about "Re: [PATCH 15/27] nVMX: Prepare vmcs02 from vmcs01 and vmcs12":
> On 10/17/2010 12:11 PM, Nadav Har'El wrote:
> >This patch contains code to prepare the VMCS which can be used to actually
> >run the L2 guest, vmcs02. prepare_vmcs02 appropriately merges the
> >information
> >in vmcs12 (the vmcs that L1 built for L2) and in vmcs01 (the vmcs that we
> >built for L1).
> >
> >VMREAD/WRITE can only access one VMCS at a time (the "current" VMCS), which
> >makes it difficult for us to read from vmcs01 while writing to vmcs12. This
> >is why we first make a copy of vmcs01 in memory (vmcs01_fields) and then
> >read that memory copy while writing to vmcs12.
> >
>
> I believe I commented on this before - you can call the same functions
> kvm uses to initialize the normal vmcs to get the common parts filled
> in.
Hi,
I'm finally attending to this issue, and you're right, for almost all fields
there's hardly a reason to read them from VMCS into a memory structure vmcs01,
when it was KVM who set these fields in the first place and can set them
again when needed in vmcs02. I'm slowly removing the fields in the vmcs01 in-
memory structure (only about a dozen left at this point!), and finally the
"vmcs12" structure contains all its fields, without another substructure
(as you asked once).
But while doing this, I came across a question that I wonder if you can
clarify for me:
Among the other things it sets up, vmx_vcpu_setup() sets
rdmsrl(MSR_IA32_SYSENTER_ESP, a);
vmcs_writel(HOST_IA32_SYSENTER_ESP, a); /* 22.2.3 */
Why is this needed here? In vmx_vcpu_load(), when a cpu is known (or changed),
we again have:
rdmsrl(MSR_IA32_SYSENTER_ESP, sysenter_esp);
vmcs_writel(HOST_IA32_SYSENTER_ESP, sysenter_esp); /* 22.2.3 */
So isn't the first setting, in vmx_vcpu_setup(), redundant?
Thanks,
Nadav.
--
Nadav Har'El | Tuesday, Feb 8 2011, 4 Adar I 5771
nyh@math.technion.ac.il |-----------------------------------------
Phone +972-523-790466, ICQ 13349191 |Earth First! We can strip-mine the other
http://nadav.harel.org.il |planets later...
next prev parent reply other threads:[~2011-02-08 12:13 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-17 10:03 [PATCH 0/27] nVMX: Nested VMX, v6 Nadav Har'El
2010-10-17 10:04 ` [PATCH 01/27] nVMX: Add "nested" module option to vmx.c Nadav Har'El
2010-10-17 10:04 ` [PATCH 02/27] nVMX: Add VMX and SVM to list of supported cpuid features Nadav Har'El
2010-10-17 10:05 ` [PATCH 03/27] nVMX: Implement VMXON and VMXOFF Nadav Har'El
2010-10-17 12:24 ` Avi Kivity
2010-10-17 12:47 ` Nadav Har'El
2010-10-17 13:07 ` Avi Kivity
2010-10-17 10:05 ` [PATCH 04/27] nVMX: Allow setting the VMXE bit in CR4 Nadav Har'El
2010-10-17 12:31 ` Avi Kivity
2010-10-17 10:06 ` [PATCH 05/27] nVMX: Introduce vmcs12: a VMCS structure for L1 Nadav Har'El
2010-10-17 12:34 ` Avi Kivity
2010-10-17 13:18 ` Nadav Har'El
2010-10-17 13:29 ` Avi Kivity
2010-10-17 10:06 ` [PATCH 06/27] nVMX: Implement reading and writing of VMX MSRs Nadav Har'El
2010-10-17 12:52 ` Avi Kivity
2010-10-17 10:07 ` [PATCH 07/27] nVMX: Decoding memory operands of VMX instructions Nadav Har'El
2010-10-17 10:07 ` [PATCH 08/27] nVMX: Hold a vmcs02 for each vmcs12 Nadav Har'El
2010-10-17 13:00 ` Avi Kivity
2010-10-17 10:08 ` [PATCH 09/27] nVMX: Success/failure of VMX instructions Nadav Har'El
2010-10-17 10:08 ` [PATCH 10/27] nVMX: Implement VMCLEAR Nadav Har'El
2010-10-17 13:05 ` Avi Kivity
2010-10-17 13:25 ` Nadav Har'El
2010-10-17 13:27 ` Avi Kivity
2010-10-17 13:37 ` Nadav Har'El
2010-10-17 14:12 ` Avi Kivity
2010-10-17 14:14 ` Gleb Natapov
2010-10-17 10:09 ` [PATCH 11/27] nVMX: Implement VMPTRLD Nadav Har'El
2010-10-17 10:09 ` [PATCH 12/27] nVMX: Implement VMPTRST Nadav Har'El
2010-10-17 10:10 ` [PATCH 13/27] nVMX: Add VMCS fields to the vmcs12 Nadav Har'El
2010-10-17 13:15 ` Avi Kivity
2010-10-17 10:10 ` [PATCH 14/27] nVMX: Implement VMREAD and VMWRITE Nadav Har'El
2010-10-17 13:25 ` Avi Kivity
2010-10-17 10:11 ` [PATCH 15/27] nVMX: Prepare vmcs02 from vmcs01 and vmcs12 Nadav Har'El
2010-10-17 14:08 ` Avi Kivity
2011-02-08 12:13 ` Nadav Har'El [this message]
2011-02-08 12:27 ` Avi Kivity
2011-02-08 12:36 ` Nadav Har'El
2011-02-08 12:39 ` Avi Kivity
2011-02-08 12:27 ` Avi Kivity
2010-10-17 10:11 ` [PATCH 16/27] nVMX: Move register-syncing to a function Nadav Har'El
2010-10-17 10:12 ` [PATCH 17/27] nVMX: Implement VMLAUNCH and VMRESUME Nadav Har'El
2010-10-17 15:06 ` Avi Kivity
2010-10-17 10:12 ` [PATCH 18/27] nVMX: No need for handle_vmx_insn function any more Nadav Har'El
2010-10-17 10:13 ` [PATCH 19/27] nVMX: Exiting from L2 to L1 Nadav Har'El
2010-10-17 15:58 ` Avi Kivity
2010-10-17 10:13 ` [PATCH 20/27] nVMX: Deciding if L0 or L1 should handle an L2 exit Nadav Har'El
2010-10-20 12:13 ` Avi Kivity
2010-10-20 14:57 ` Avi Kivity
2010-10-17 10:14 ` [PATCH 21/27] nVMX: Correct handling of interrupt injection Nadav Har'El
2010-10-17 10:14 ` [PATCH 22/27] nVMX: Correct handling of exception injection Nadav Har'El
2010-10-17 10:15 ` [PATCH 23/27] nVMX: Correct handling of idt vectoring info Nadav Har'El
2010-10-17 10:15 ` [PATCH 24/27] nVMX: Handling of CR0.TS and #NM for Lazy FPU loading Nadav Har'El
2010-10-17 10:16 ` [PATCH 25/27] nVMX: Additional TSC-offset handling Nadav Har'El
2010-10-19 19:13 ` Zachary Amsden
2010-10-17 10:16 ` [PATCH 26/27] nVMX: Miscellenous small corrections Nadav Har'El
2010-10-17 10:17 ` [PATCH 27/27] nVMX: Documentation Nadav Har'El
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=20110208121315.GA28897@fermat.math.technion.ac.il \
--to=nyh@math.technion.ac.il \
--cc=avi@redhat.com \
--cc=gleb@redhat.com \
--cc=kvm@vger.kernel.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).