[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 3/3 V3] XSA-60 security hole: cr0.cd handling
Jan Beulich wrote: On 21.10.13 at 17:55, "Liu, Jinsong" <jinsong.liu@xxxxxxxxx> wrote:From 4ff1e2955f67954e60562b29a00adea89e5b93ae Mon Sep 17 00:00:00 2001 From: Liu Jinsong <jinsong.liu@xxxxxxxxx> Date: Thu, 17 Oct 2013 05:49:23 +0800 Subject: [PATCH 3/3 V3] XSA-60 security hole: cr0.cd handling This patch solves XSA-60 security hole: 1. For guest w/o VT-d, and for guest with VT-d but snooped, Xen need do nothing, since hardware snoop mechanism has ensured cache coherency. 2. For guest with VT-d but non-snooped, cache coherency can not be guaranteed by h/w snoop, therefore it need emulate UC type to guest: 2.1). if it works w/ Intel EPT, set guest IA32_PAT fields as UC so that guest memory type are all UC. 2.2). if it works w/ shadow, drop all shadows so that any new ones would be created on demand w/ UC. This patch also fix a bug of shadow cr0.cd setting. Current shadow has a small window between cache flush and TLB invalidation, resulting in possilbe cache pollution. This patch pause vcpus so that no vcpus context involvedinto the window.Signed-off-by: Liu Jinsong <jinsong.liu@xxxxxxxxx>This looks fine to me now, but will need acks/reviews at least from - Keir (whose blessing of the pausing construct I'd like to have even if this didn't involve changing non-x86 files) - one of the VMX maintainers - one or both of Tim and Andrew And of course I'd really appreciate if Oracle could arrange for testing this, to confirm their performance problem is also gone with this. I am try finding an env to test it. I'll reply after test. zduan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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