On Thu, Oct 03, 2013 at 08:24:57AM +0200, Albert ARIBAUD wrote: > Hi Andre, > > On Thu, 19 Sep 2013 18:06:45 +0200, Andre Przywara > <andre.przywara@xxxxxxxxxx> wrote: > > > For the KVM and XEN hypervisors to be usable, we need to enter the > > kernel in HYP mode. Now that we already are in non-secure state, > > HYP mode switching is within short reach. > > > > While doing the non-secure switch, we have to enable the HVC > > instruction and setup the HYP mode HVBAR (while still secure). > > > > The actual switch is done by dropping back from a HYP mode handler > > without actually leaving HYP mode, so we introduce a new handler > > routine in our new secure exception vector table. > > > > In the assembly switching routine we save and restore the banked LR > > and SP registers around the hypercall to do the actual HYP mode > > switch. > > > > The C routine first checks whether we are in HYP mode already and > > also whether the virtualization extensions are available. It also > > checks whether the HYP mode switch was finally successful. > > The bootm command part only calls the new function after the > > non-secure switch. > > > > Signed-off-by: Andre Przywara <andre.przywara@xxxxxxxxxx> > > --- > > arch/arm/cpu/armv7/Makefile | 2 +- > > arch/arm/cpu/armv7/nonsec_virt.S | 43 +++++++++++++++++++++++++++++++++++----- > > arch/arm/cpu/armv7/virt-v7.c | 37 ++++++++++++++++++++++++++++++++++ > > arch/arm/include/asm/armv7.h | 6 ++++-- > > arch/arm/lib/bootm.c | 7 ++++++- > > 5 files changed, 86 insertions(+), 9 deletions(-) > > > > Changes: > > v3..v4: w/s fixes, embed error output > > v4..v5: none > > Seems like Christoffer's comment was not addressed here but IIUC, it > was in other files (Christoffer, feel free to comment). Any reason why > the "older asm" comments form was not replaced in here? > I think these comments are a bit superflous, but not exactly harmful, so I didn't raise the flag when they were not corrected. My thought was that if you're building for a board that has support for the virtualization extensions you should be using a toolchain that knows about them too, but Andre pointed out that his (I think Debian) still used an old enough cross toolchain not to have this support. In any case, I don't think this warrants holding back the patches but can be fixed as a follow-up if the community agrees that we need to support older toolchains by some define that encodes the hvc and eret instructions properly. Thanks, -Christoffer _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
