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[Xen-devel] Re: [RFC, PATCH 8/24] i386 Vmi syscall assembly
- To: Zachary Amsden <zach@xxxxxxxxxx>
- From: Chris Wright <chrisw@xxxxxxxxxxxx>
- Date: Tue, 14 Mar 2006 19:01:15 -0800
- Cc: Andrew Morton <akpm@xxxxxxxx>, Joshua LeVasseur <jtl@xxxxxxxxxx>, Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, Pratap Subrahmanyam <pratap@xxxxxxxxxx>, Wim Coekaerts <wim.coekaerts@xxxxxxxxxx>, Chris Wright <chrisw@xxxxxxxx>, Jack Lo <jlo@xxxxxxxxxx>, Dan Hecht <dhecht@xxxxxxxxxx>, Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>, Jan Beulich <jbeulich@xxxxxxxxxx>, Christopher Li <chrisl@xxxxxxxxxx>, Virtualization Mailing List <virtualization@xxxxxxxxxxxxxx>, Linus Torvalds <torvalds@xxxxxxxx>, Anne Holler <anne@xxxxxxxxxx>, Jyothy Reddy <jreddy@xxxxxxxxxx>, Kip Macy <kmacy@xxxxxxxxxxx>, Ky Srinivasan <ksrinivasan@xxxxxxxxxx>, Leendert van Doorn <leendert@xxxxxxxxxxxxxx>, Dan Arai <arai@xxxxxxxxxx>
- Delivery-date: Wed, 15 Mar 2006 10:19:58 +0000
- List-id: Xen developer discussion <xen-devel.lists.xensource.com>
* Zachary Amsden (zach@xxxxxxxxxx) wrote:
> These changes are sufficient to glue the Linux low level entry points to
> hypervisor event injection by emulating the native processor exception
> frame interface.
There's a bit more going on in the Xen changes to entry.S. The STI/CLI
abstraction definitely gets partway there. Then there's some bits that
use (in your terms) __STI, __CLI. It's in code that's a pure addition
so it's tempting to simply make a mechanism for the additions, but it's a bit
too intertwined to just separate that code, as there's calls from core
entry.S into the Xen additions.
> N.B. Sti; Sysexit is a required abstraction, as the STI instruction implies
> holdoff of interrupts, which is destroyed by any NOP padding.
Or just disable systenter ;-) Random question...do you support systenter?
Sounds slower than int80, since it should require 3->0->1->0->3 transitions.
Just idly curious if you've done benchmarks to see the difference.
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