On Wed, Jul 25, 2018 at 04:41:44PM +0100, Alex Bennée wrote: > > Dave Martin <Dave.Martin@xxxxxxx> writes: > > > On Wed, Jul 25, 2018 at 03:12:15PM +0100, Alex Bennée wrote: > >> > >> Dave Martin <Dave.Martin@xxxxxxx> writes: > >> > >> > Some system registers may or may not logically exist for a vcpu > >> > depending on whether certain architectural features are enabled for > >> > the vcpu. > >> > > >> > In order to avoid spuriously emulating access to these registers > >> > when they should not exist, or allowing the registers to be > >> > spuriously enumerated or saved/restored through the ioctl > >> > interface, a means is needed to allow registers to be hidden > >> > depending on the vcpu configuration. > >> > > >> > In order to support this in a flexible way, this patch adds a > >> > check_present() method to struct sys_reg_desc, and updates the > >> > generic system register access and enumeration code to be aware of > >> > it: if check_present() returns false, the code behaves as if the > >> > register did not exist. > >> > > >> > For convenience, the complete check is wrapped up in a new helper > >> > sys_reg_present(). > >> > > >> > An attempt has been made to hook the new check into the generic > >> > accessors for trapped system registers. This should reduce the > >> > potential for future surprises, although the redundant check will > >> > add a small cost. No system register depends on this functionality > >> > yet, and some paths needing the check may also need attention. > >> > > >> > Naturally, this facility makes sense only for registers that are > >> > trapped. > >> > > >> > Signed-off-by: Dave Martin <Dave.Martin@xxxxxxx> > >> > --- > >> > arch/arm64/kvm/sys_regs.c | 20 +++++++++++++++----- > >> > arch/arm64/kvm/sys_regs.h | 11 +++++++++++ > >> > 2 files changed, 26 insertions(+), 5 deletions(-) > > > > [...] > > > >> > diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h > >> > index cd710f8..dfbb342 100644 > >> > --- a/arch/arm64/kvm/sys_regs.h > >> > +++ b/arch/arm64/kvm/sys_regs.h > >> > @@ -22,6 +22,9 @@ > >> > #ifndef __ARM64_KVM_SYS_REGS_LOCAL_H__ > >> > #define __ARM64_KVM_SYS_REGS_LOCAL_H__ > >> > > >> > +#include <linux/compiler.h> > >> > +#include <linux/types.h> > >> > >> I can see why you want compiler.h, but why types.h? > > > > For bool (though it felt a bit pedantic). > > It must be picked up elsewhere because it didn't fail when I rebuilt > without it - and the header has been happily using bool up to that > point. Sure, lots of headers include linux/types.h, so we get away with it all over the place. I was adding it for completeness really: I prefer not to rely on headers being included by accident. Cheers ---Dave _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
