From mboxrd@z Thu Jan 1 00:00:00 1970 From: christoffer.dall@linaro.org (Christoffer Dall) Date: Sun, 25 Aug 2013 17:46:16 -0700 Subject: [PATCH 2/3] KVM: ARM: Get rid of KVM_HPAGE_ defines In-Reply-To: References: <1376021239-10532-1-git-send-email-christoffer.dall@linaro.org> <1376058613-26400-1-git-send-email-christoffer.dall@linaro.org> <20130825140529.GT8218@redhat.com> <20130825144847.GV8218@redhat.com> Message-ID: <20130826004616.GA13231@cbox> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Sun, Aug 25, 2013 at 04:18:02PM +0100, Peter Maydell wrote: > On 25 August 2013 15:48, Gleb Natapov wrote: > > On Sun, Aug 25, 2013 at 03:29:17PM +0100, Peter Maydell wrote: > >> Smiley noted, but this is pretty unlikely since it's not possible > >> to lie to the guest about which mode it's in, so you can't make > >> a guest think it's in Hyp mode. > >> > > I suspected this, but forgot most that I read about Hyp mode by now. > > Need to refresh my memory ASAP. Is it impossible even with a lot of > > emulation? Can guest detect that it is not in a Hyp mode without > > trapping into hypervisor? > > Yes. The current mode is in the the low bits of the CPSR, which > is readable without causing a trap. This is just the most obvious > roadblock; I bet there are more. If you really had to run Hyp mode > code in a VM you probably have to do it by having it all emulated > via TCG. > Or through some highly paravirtualized nested virtualization solution if that is ever relevant. -Christoffer