linux-arm-kernel.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: peter.maydell@linaro.org (Peter Maydell)
To: linux-arm-kernel@lists.infradead.org
Subject: [kvmarm] [PATCH 14/29] arm64: KVM: guest one-reg interface
Date: Thu, 14 Mar 2013 08:57:33 +0000	[thread overview]
Message-ID: <CAFEAcA8DkB0tMN6V1fi=teujm0hWji-O9ZF8+iOswTOihEjFcA@mail.gmail.com> (raw)
In-Reply-To: <5140E2C0.7010009@codeaurora.org>

On 13 March 2013 20:34, Christopher Covington <cov@codeaurora.org> wrote:
> My guess at the goal of the code cited above in this email is that it's trying
> to sanity check that virtualization will work. Rather than taking a default
> deny approach with a hand-maintained white list of virtualization-supporting
> machine identifiers, why not check that EL2 is implemented on the current
> system and if it's not implied by that, that the timer and interrupt
> controller are suitable as well?

I think the question of "how much do we need to virtualize to allow
us to expose a different CPU to the guest than the host" is not yet
one that's been answered; so for the moment we support only
"guest == host == A57" [or == A15 on armv7]. When somebody has added
support for a second type of host/guest CPU then I think the process
of going through that work will make it much clearer how much
'new cpu' support is needed and what can be coded to work with any
virt-capable cpu. Until then I think it's safer to simply lock out
the unsupported combinations. That way anybody trying to run KVM on
a different CPU will be able to see that they have work to do and it's
not expected to work out of the box just yet.

We don't support other guests than A57 currently because you need to
implement emulation code for the imp-def registers for a guest CPU.
Again, I suspect the process of adding support for a 2nd guest CPU
will make it obvious what can be done generically and what really
does need to be per-CPU.

One thing I'm a bit worried about is the possibility that we accidentally
by-default allow the guest access to some new sysreg that didn't
exist on the A57 [or A15 for 32 bit] that turns out to be a security
hole (since both guest and host kernel run at EL1). But I think
trapping the whole of the impdef sysreg space should cover that.

-- PMM

  reply	other threads:[~2013-03-14  8:57 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-05  3:47 [PATCH 00/29] Port of KVM to arm64 Marc Zyngier
2013-03-05  3:47 ` [PATCH 01/29] arm64: KVM: define HYP and Stage-2 translation page flags Marc Zyngier
2013-03-05  3:47 ` [PATCH 02/29] arm64: KVM: HYP mode idmap support Marc Zyngier
2013-03-05  3:47 ` [PATCH 03/29] arm64: KVM: EL2 register definitions Marc Zyngier
2013-03-05  3:47 ` [PATCH 04/29] arm64: KVM: system register definitions for 64bit guests Marc Zyngier
2013-03-07 10:33   ` [kvmarm] " Alexander Graf
2013-03-08  3:23     ` Marc Zyngier
2013-03-12 13:20   ` Christopher Covington
2013-03-12 13:41     ` Christopher Covington
2013-03-12 13:50     ` Marc Zyngier
2013-03-05  3:47 ` [PATCH 05/29] arm64: KVM: Basic ESR_EL2 helpers and vcpu register access Marc Zyngier
2013-03-16  0:55   ` Geoff Levand
2013-03-05  3:47 ` [PATCH 06/29] arm64: KVM: fault injection into a guest Marc Zyngier
2013-03-12 13:20   ` Christopher Covington
2013-03-12 14:25     ` Marc Zyngier
2013-03-16  1:03   ` Geoff Levand
2013-03-05  3:47 ` [PATCH 07/29] arm64: KVM: architecture specific MMU backend Marc Zyngier
2013-03-05  3:47 ` [PATCH 08/29] arm64: KVM: user space interface Marc Zyngier
2013-03-07  8:09   ` Michael S. Tsirkin
2013-03-08  3:46     ` [kvmarm] " Marc Zyngier
2013-03-10  9:23       ` Michael S. Tsirkin
2013-03-05  3:47 ` [PATCH 09/29] arm64: KVM: system register handling Marc Zyngier
2013-03-07 10:30   ` [kvmarm] " Alexander Graf
2013-03-08  3:29     ` Marc Zyngier
2013-03-25  8:19     ` Marc Zyngier
2013-04-23 23:07       ` Christoffer Dall
2013-03-05  3:47 ` [PATCH 10/29] arm64: KVM: Cortex-A57 specific system registers handling Marc Zyngier
2013-03-13 18:30   ` Christopher Covington
2013-03-14 10:26     ` Marc Zyngier
2013-03-05  3:47 ` [PATCH 11/29] arm64: KVM: virtual CPU reset Marc Zyngier
2013-03-05  3:47 ` [PATCH 12/29] arm64: KVM: kvm_arch and kvm_vcpu_arch definitions Marc Zyngier
2013-03-12 17:30   ` Christopher Covington
2013-03-05  3:47 ` [PATCH 13/29] arm64: KVM: MMIO access backend Marc Zyngier
2013-03-05  3:47 ` [PATCH 14/29] arm64: KVM: guest one-reg interface Marc Zyngier
2013-03-12 17:31   ` Christopher Covington
2013-03-12 18:05     ` Marc Zyngier
2013-03-12 22:07       ` Christopher Covington
2013-03-13  7:48         ` Marc Zyngier
2013-03-13 20:34           ` Christopher Covington
2013-03-14  8:57             ` Peter Maydell [this message]
2013-03-20 20:06               ` [kvmarm] " Christopher Covington
2013-03-05  3:47 ` [PATCH 15/29] arm64: KVM: hypervisor initialization code Marc Zyngier
2013-03-05  3:47 ` [PATCH 16/29] arm64: KVM: HYP mode world switch implementation Marc Zyngier
2013-03-13 19:59   ` Christopher Covington
2013-03-20 20:04     ` Christopher Covington
2013-03-21 11:54       ` Marc Zyngier
2013-03-05  3:47 ` [PATCH 17/29] arm64: KVM: Exit handling Marc Zyngier
2013-03-05  3:47 ` [PATCH 18/29] arm64: KVM: Plug the VGIC Marc Zyngier
2013-03-05  3:47 ` [PATCH 19/29] arm64: KVM: Plug the arch timer Marc Zyngier
2013-03-05  3:47 ` [PATCH 20/29] arm64: KVM: PSCI implementation Marc Zyngier
2013-03-05  3:47 ` [PATCH 21/29] arm64: KVM: Build system integration Marc Zyngier
2013-03-05  3:47 ` [PATCH 22/29] arm64: KVM: define 32bit specific registers Marc Zyngier
2013-03-18 17:03   ` Christopher Covington
2013-03-05  3:47 ` [PATCH 23/29] arm64: KVM: 32bit GP register access Marc Zyngier
2013-03-16  0:24   ` Geoff Levand
2013-03-05  3:47 ` [PATCH 24/29] arm64: KVM: 32bit conditional execution emulation Marc Zyngier
2013-03-18 17:04   ` Christopher Covington
2013-03-05  3:47 ` [PATCH 25/29] arm64: KVM: 32bit handling of coprocessor traps Marc Zyngier
2013-03-05  3:47 ` [PATCH 26/29] arm64: KVM: 32bit coprocessor access for Cortex-A57 Marc Zyngier
2013-03-05  3:47 ` [PATCH 27/29] arm64: KVM: 32bit specific register world switch Marc Zyngier
2013-03-05  3:47 ` [PATCH 28/29] arm64: KVM: 32bit guest fault injection Marc Zyngier
2013-03-18 18:45   ` Christopher Covington
2013-03-05  3:47 ` [PATCH 29/29] arm64: KVM: enable initialization of a 32bit vcpu Marc Zyngier
2013-03-18 18:56   ` Christopher Covington

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='CAFEAcA8DkB0tMN6V1fi=teujm0hWji-O9ZF8+iOswTOihEjFcA@mail.gmail.com' \
    --to=peter.maydell@linaro.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    /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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).