[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Xen-devel] Hypercalls in Intel-VT
- To: "Dong, Eddie" <eddie.dong@xxxxxxxxx>
- From: "Ashish Bijlani" <ashish.bijlani@xxxxxxxxx>
- Date: Mon, 29 Oct 2007 02:41:38 -0400
- Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
- Delivery-date: Sun, 28 Oct 2007 23:42:16 -0700
- Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:references; b=C1rMfdw4gZ134O0DfpRSoz6vkB/pH8TLNBhspcDI6EsY1YrqSx5JCzzKY7CrW980OB6P101f48f4yYtCBwxnc7+Xp1nURnHrB5APBRrVTOSBa27YOtdU6rbe7NzamHG6J04nbrkHvgyEUbp1m82uOJ9SRRewOIXZ1GwHgffMCfs=
- List-id: Xen developer discussion <xen-devel.lists.xensource.com>
so does xen use a different GDT or it uses a different slot inside the same GDT? also, does xen use a different ss and esp than guest os krnl or it operates on the guest os krnl?
On 10/29/07,
Dong, Eddie <eddie.dong@xxxxxxxxx> wrote:
GDTR BASE & Limit are part of Host/Guest state which
will be save/restored.
Eddie
does transition from non-root VMX mode to root VMX mode require GDT
switch i.e. does GDT change from guest OS krnl's GDT to xen's GDT?
On 10/28/07, Tim
Deegan <Tim.Deegan@xxxxxxxxxxxxx>
wrote:
At
02:55 +0100 on 27 Oct (1193453721), Mark Williamson wrote: > Regarding
the TLB flush, again, the hardware quite possibly does
that. But > I'm not aware of anything in the VMX spec that
exposes this detail, so Intel > could easily tag the TLB entries as
root / non-root to avoid flushing on a > VMEXIT /
VMENTER. For all I know, they may do this already!
Right
now, Intel processors always flush the whole TLB (including global
entries) on a transition to or from non-root mode. Newer AMD
processors have tagged TLBs so you can do an exit/enter without flushing,
but you have to explicitly discard the guest entries when it's
appropriate. (Look at
arch/x86/hvm/svm/asid.c). That's on the road map for Intel too,
I believe.
Cheers,
Tim.
-- Tim Deegan <Tim.Deegan@xxxxxxxxxxxxx>,
XenSource UK Limited Registered office c/o EC2Y 5EB, UK; company number
05334508
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|