From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andre Przywara Date: Fri, 31 May 2013 08:36:12 +0200 Subject: [U-Boot] [PATCH 0/6] ARMv7: Add HYP mode switching support In-Reply-To: <20130531061115.GG3189@ubuntu> References: <1367846270-1827-1-git-send-email-andre.przywara@linaro.org> <20130531061115.GG3189@ubuntu> Message-ID: <51A844DC.8010303@linaro.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 05/31/2013 08:11 AM, Christoffer Dall wrote: > On Mon, May 06, 2013 at 03:17:44PM +0200, Andre Przywara wrote: >> (for GIT URL and Changelog see below) >> >> ARM CPUs with the virtualization extension have a new mode called >> HYP mode, which allows hypervisors to safely control and monitor >> guests. The current hypervisor (KVM and Xen) implementations >> require the kernel to be entered in that HYP mode. >> >> This patch series introduces a configuration variable >> CONFIG_ARMV7_VIRT which enables code to switch all cores into HYP >> mode. This is done automatically during execution of the bootm >> command (but could also be done earlier - U-Boot runs fine in HYP >> mode without MMU usage). > > I forget the u-boot specifics here, but if you boot over networking, for > example, does that eventually end up calling bootm or would Hyp mode not > be entered in this case? Despite the naming "bootm" is eventually always called when booting Linux, even bootz is a wrapper around this. Same with network boot. So unless you show me a case where this isn't, I think this is fine. Regards, Andre. > I'm only raising this issue because it's important to minimize the hoops > and efforts for booting in Hyp mode, since it's harmless to do so > regardless of the linux kernel we're booting. > > [...] > > -Christoffer >