From: Paolo Bonzini <pbonzini@redhat.com>
To: "Yao, Jiewen" <jiewen.yao@intel.com>
Cc: "Chen, Yingwen" <yingwen.chen@intel.com>,
"devel@edk2.groups.io" <devel@edk2.groups.io>,
Phillip Goerl <phillip.goerl@oracle.com>,
qemu devel list <qemu-devel@nongnu.org>,
Alex Williamson <alex.williamson@redhat.com>,
"Nakajima, Jun" <jun.nakajima@intel.com>,
Igor Mammedov <imammedo@redhat.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
edk2-rfc-groups-io <rfc@edk2.groups.io>,
Laszlo Ersek <lersek@redhat.com>,
Joao Marcal Lemos Martins <joao.m.martins@oracle.com>
Subject: Re: [Qemu-devel] [edk2-devel] CPU hotplug using SMM with QEMU+OVMF
Date: Mon, 19 Aug 2019 16:10:43 +0200 [thread overview]
Message-ID: <4afa24cb-1ab7-b085-ba84-70271712d62e@redhat.com> (raw)
In-Reply-To: <D2A45071-A097-4642-A34C-6B7C5D7D2466@intel.com>
On 19/08/19 01:00, Yao, Jiewen wrote:
> in real world, we deprecate AB-seg usage because they are vulnerable
> to smm cache poison attack. I assume cache poison is out of scope in
> the virtual world, or there is a way to prevent ABseg cache poison.
Indeed the SMRR would not cover the A-seg on real hardware. However, if
the chipset allowed aliasing A-seg SMRAM to 0x30000, it would only be
used for SMBASE relocation of hotplugged CPU. The firmware would still
keep low SMRAM disabled, *except around SMBASE relocation of hotplugged
CPUs*. To avoid cache poisoning attacks, you only have to issue a
WBINVD before enabling low SMRAM and before disabling it. Hotplug SMI
is not a performance-sensitive path, so it's not a big deal.
So I guess you agree that PCI DMA attacks are a potential vector also on
real hardware. As Alex pointed out, VT-d is not a solution because
there could be legitimate DMA happening during CPU hotplug. For OVMF
we'll probably go with Igor's idea, it would be nice if Intel chipsets
supported it too. :)
Paolo
next prev parent reply other threads:[~2019-08-19 14:11 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-13 14:16 [Qemu-devel] CPU hotplug using SMM with QEMU+OVMF Laszlo Ersek
2019-08-13 16:09 ` Laszlo Ersek
2019-08-13 16:18 ` Laszlo Ersek
2019-08-14 13:20 ` Yao, Jiewen
2019-08-14 14:04 ` Paolo Bonzini
2019-08-15 9:55 ` Yao, Jiewen
2019-08-15 16:04 ` Paolo Bonzini
2019-08-15 15:00 ` [Qemu-devel] [edk2-devel] " Laszlo Ersek
2019-08-15 16:16 ` Igor Mammedov
2019-08-15 16:21 ` Paolo Bonzini
2019-08-16 2:46 ` Yao, Jiewen
2019-08-16 7:20 ` Paolo Bonzini
2019-08-16 7:49 ` Yao, Jiewen
2019-08-16 20:15 ` Laszlo Ersek
2019-08-16 22:19 ` Alex Williamson
2019-08-17 0:20 ` Yao, Jiewen
2019-08-18 19:50 ` Paolo Bonzini
2019-08-18 23:00 ` Yao, Jiewen
2019-08-19 14:10 ` Paolo Bonzini [this message]
2019-08-21 12:07 ` Laszlo Ersek
[not found] ` <E92EE9817A31E24EB0585FDF735412F5B9D9C671@ORSMSX113.amr.corp.intel.com>
2019-08-21 17:05 ` [Qemu-devel] [edk2-rfc] " Paolo Bonzini
[not found] ` <E92EE9817A31E24EB0585FDF735412F5B9D9D74A@ORSMSX113.amr.corp.intel.com>
2019-08-21 17:39 ` Paolo Bonzini
2019-08-21 20:17 ` Kinney, Michael D
2019-08-22 6:18 ` Paolo Bonzini
2019-08-22 18:29 ` Laszlo Ersek
2019-08-22 18:51 ` Paolo Bonzini
2019-08-23 14:53 ` Laszlo Ersek
2019-08-22 20:13 ` Kinney, Michael D
2019-08-22 17:59 ` Laszlo Ersek
2019-08-22 18:43 ` Paolo Bonzini
2019-08-22 20:06 ` Kinney, Michael D
2019-08-22 22:18 ` Paolo Bonzini
2019-08-22 22:32 ` Kinney, Michael D
2019-08-22 23:11 ` Paolo Bonzini
2019-08-23 1:02 ` Kinney, Michael D
2019-08-23 5:00 ` Yao, Jiewen
2019-08-23 15:25 ` Kinney, Michael D
2019-08-24 1:48 ` Yao, Jiewen
2019-08-27 18:31 ` Igor Mammedov
2019-08-29 17:01 ` Laszlo Ersek
2019-08-30 14:48 ` Igor Mammedov
2019-08-30 18:46 ` Laszlo Ersek
2019-09-02 8:45 ` Igor Mammedov
2019-09-02 19:09 ` Laszlo Ersek
2019-09-03 14:53 ` Igor Mammedov
2019-09-03 17:20 ` Laszlo Ersek
2019-09-04 9:52 ` Igor Mammedov
2019-09-05 13:08 ` Laszlo Ersek
2019-09-05 15:45 ` Igor Mammedov
2019-09-05 15:49 ` [Qemu-devel] [PATCH] q35: lpc: allow to lock down 128K RAM at default SMBASE address Igor Mammedov
2019-09-09 19:15 ` Laszlo Ersek
2019-09-09 19:20 ` Laszlo Ersek
2019-09-10 15:58 ` Igor Mammedov
2019-09-11 17:30 ` Laszlo Ersek
2019-09-17 13:11 ` [Qemu-devel] [edk2-devel] " Igor Mammedov
2019-08-26 15:30 ` [Qemu-devel] [edk2-rfc] [edk2-devel] CPU hotplug using SMM with QEMU+OVMF Laszlo Ersek
2019-08-27 16:23 ` Igor Mammedov
2019-08-27 20:11 ` Laszlo Ersek
2019-08-28 12:01 ` Igor Mammedov
2019-08-29 16:25 ` Laszlo Ersek
2019-08-30 13:49 ` Igor Mammedov
2019-08-22 17:53 ` Laszlo Ersek
2019-08-16 20:00 ` [Qemu-devel] " Laszlo Ersek
2019-08-15 16:07 ` [Qemu-devel] " Igor Mammedov
2019-08-15 16:24 ` Paolo Bonzini
2019-08-16 7:42 ` Igor Mammedov
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=4afa24cb-1ab7-b085-ba84-70271712d62e@redhat.com \
--to=pbonzini@redhat.com \
--cc=alex.williamson@redhat.com \
--cc=boris.ostrovsky@oracle.com \
--cc=devel@edk2.groups.io \
--cc=imammedo@redhat.com \
--cc=jiewen.yao@intel.com \
--cc=joao.m.martins@oracle.com \
--cc=jun.nakajima@intel.com \
--cc=lersek@redhat.com \
--cc=phillip.goerl@oracle.com \
--cc=qemu-devel@nongnu.org \
--cc=rfc@edk2.groups.io \
--cc=yingwen.chen@intel.com \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.