From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: long latency of domain shutdown Date: Mon, 28 Apr 2008 15:42:09 +0100 Message-ID: References: <4815FBB8.76E4.0078.0@novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4815FBB8.76E4.0078.0@novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Jan Beulich Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org On 28/4/08 15:30, "Jan Beulich" wrote: > Okay, thanks - so I indeed missed the call to hypercall_preempt_check() > in relinquish_memory(), which is the key indicator here. > > However, that change deals exclusively with domain shutdown, but not > with the more general page table pinning/unpinning operations, which I > believe are (as described) vulnerable to mis-use by a malicious guest (I > realize that well behaved guests would not normally present a heavily > populated address space here, but it also cannot be entirely excluded) > - the upper bound to the number of operations on x86-64 is 512**4 > or 2**36 l1 table entries (ignoring the hypervisor hole which doesn't > need processing). True. It turns out to be good enough in practice though. -- Keir