From mboxrd@z Thu Jan 1 00:00:00 1970 From: christoffer.dall@linaro.org (Christoffer Dall) Date: Wed, 6 Apr 2016 13:32:13 +0200 Subject: [PATCH] arm64: KVM: Warn when PARange is less than 40 bits In-Reply-To: <1459869107-6367-1-git-send-email-marc.zyngier@arm.com> References: <1459869107-6367-1-git-send-email-marc.zyngier@arm.com> Message-ID: <20160406113213.GB16355@cbox> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 Reviewed-by: Christoffer Dall