From: Christoffer Dall <christoffer.dall@linaro.org>
To: Marc Zyngier <marc.zyngier@arm.com>
Cc: kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arm64: KVM: Warn when PARange is less than 40 bits
Date: Wed, 6 Apr 2016 13:32:13 +0200 [thread overview]
Message-ID: <20160406113213.GB16355@cbox> (raw)
In-Reply-To: <1459869107-6367-1-git-send-email-marc.zyngier@arm.com>
On Tue, Apr 05, 2016 at 04:11:47PM +0100, Marc Zyngier wrote:
> We always thought that 40bits of PA range would be the minimum people
> would actually build. Anything less is terrifyingly small.
>
> Turns out that we were both right and wrong. Nobody has ever built
> such a system, but the ARM Foundation Model has a PARange set to 36bits.
> Just because we can. Oh well. Now, the KVM API explicitely says that
> we offer a 40bit PA space to the VM, so we shouldn't run KVM on
> the Foundation Model at all.
>
> That being said, this patch offers a less agressive alternative, and
> loudly warns about the configuration being unsupported. You'll still
> be able to run VMs (at your own risks, though).
>
> This is just a workaround until we have a proper userspace API where
> we report the PARange to userspace.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
WARNING: multiple messages have this Message-ID (diff)
From: christoffer.dall@linaro.org (Christoffer Dall)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: KVM: Warn when PARange is less than 40 bits
Date: Wed, 6 Apr 2016 13:32:13 +0200 [thread overview]
Message-ID: <20160406113213.GB16355@cbox> (raw)
In-Reply-To: <1459869107-6367-1-git-send-email-marc.zyngier@arm.com>
On Tue, Apr 05, 2016 at 04:11:47PM +0100, Marc Zyngier wrote:
> We always thought that 40bits of PA range would be the minimum people
> would actually build. Anything less is terrifyingly small.
>
> Turns out that we were both right and wrong. Nobody has ever built
> such a system, but the ARM Foundation Model has a PARange set to 36bits.
> Just because we can. Oh well. Now, the KVM API explicitely says that
> we offer a 40bit PA space to the VM, so we shouldn't run KVM on
> the Foundation Model at all.
>
> That being said, this patch offers a less agressive alternative, and
> loudly warns about the configuration being unsupported. You'll still
> be able to run VMs (at your own risks, though).
>
> This is just a workaround until we have a proper userspace API where
> we report the PARange to userspace.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
next prev parent reply other threads:[~2016-04-06 11:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-05 15:11 [PATCH] arm64: KVM: Warn when PARange is less than 40 bits Marc Zyngier
2016-04-05 15:11 ` Marc Zyngier
2016-04-06 11:32 ` Christoffer Dall [this message]
2016-04-06 11:32 ` Christoffer Dall
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=20160406113213.GB16355@cbox \
--to=christoffer.dall@linaro.org \
--cc=kvmarm@lists.cs.columbia.edu \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=marc.zyngier@arm.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.