On Wed, Nov 08, 2017 at 10:32:30AM +0100, Andrew Jones wrote:
> On Thu, Oct 12, 2017 at 12:41:21PM +0200, Christoffer Dall wrote:
> > There's a semantic difference between the EL1 registers that control
> > operation of a kernel running in EL1 and EL1 registers that only control
> > userspace execution in EL0. Since we can defer saving/restoring the
> > latter, move them into their own function.
> >
> > We also take this chance to rename the function saving/restoring the
> > remaining system register to make it clear this function deals with
> > the EL1 system registers.
> >
> > No functional change.
> >
> > Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
> > ---
> > arch/arm64/kvm/hyp/sysreg-sr.c | 34 +++++++++++++++++++++++-----------
> > 1 file changed, 23 insertions(+), 11 deletions(-)
> >
> > diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
> > index c4a3714..193c2b0 100644
> > --- a/arch/arm64/kvm/hyp/sysreg-sr.c
> > +++ b/arch/arm64/kvm/hyp/sysreg-sr.c
> > @@ -34,14 +34,18 @@ static void __hyp_text __sysreg_do_nothing(struct kvm_cpu_context *ctxt) { }
> >
> > static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
> > {
> > + ctxt->sys_regs[MDSCR_EL1] = read_sysreg(mdscr_el1);
> > + ctxt->gp_regs.regs.sp = read_sysreg(sp_el0);
>
> Maybe a comment stating that sp_el0 is here, instead of down in user
> state, because arm64 Linux chooses to use it for the 'current' pointer.
> At least that's why I think it's been promoted to common state, but maybe
> there was a different reason I missed.
>
That is the reason. I can add a comment.
> > +}
> > +
> > +static void __hyp_text __sysreg_save_user_state(struct kvm_cpu_context *ctxt)
> > +{
> > ctxt->sys_regs[ACTLR_EL1] = read_sysreg(actlr_el1);
> > ctxt->sys_regs[TPIDR_EL0] = read_sysreg(tpidr_el0);
> > ctxt->sys_regs[TPIDRRO_EL0] = read_sysreg(tpidrro_el0);
> > - ctxt->sys_regs[MDSCR_EL1] = read_sysreg(mdscr_el1);
> > - ctxt->gp_regs.regs.sp = read_sysreg(sp_el0);
> > }
> >
> > -static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
> > +static void __hyp_text __sysreg_save_el1_state(struct kvm_cpu_context *ctxt)
> > {
> > ctxt->sys_regs[MPIDR_EL1] = read_sysreg(vmpidr_el2);
> > ctxt->sys_regs[CSSELR_EL1] = read_sysreg(csselr_el1);
> > @@ -70,31 +74,37 @@ static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
> > }
> >
> > static hyp_alternate_select(__sysreg_call_save_host_state,
> > - __sysreg_save_state, __sysreg_do_nothing,
> > + __sysreg_save_el1_state, __sysreg_do_nothing,
> > ARM64_HAS_VIRT_HOST_EXTN);
> >
> > void __hyp_text __sysreg_save_host_state(struct kvm_cpu_context *ctxt)
> > {
> > __sysreg_call_save_host_state()(ctxt);
> > __sysreg_save_common_state(ctxt);
> > + __sysreg_save_user_state(ctxt);
> > }
> >
> > void __hyp_text __sysreg_save_guest_state(struct kvm_cpu_context *ctxt)
> > {
> > - __sysreg_save_state(ctxt);
> > + __sysreg_save_el1_state(ctxt);
> > __sysreg_save_common_state(ctxt);
> > + __sysreg_save_user_state(ctxt);
> > }
> >
> > static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctxt)
> > {
> > - write_sysreg(ctxt->sys_regs[ACTLR_EL1], actlr_el1);
> > - write_sysreg(ctxt->sys_regs[TPIDR_EL0], tpidr_el0);
> > - write_sysreg(ctxt->sys_regs[TPIDRRO_EL0], tpidrro_el0);
> > write_sysreg(ctxt->sys_regs[MDSCR_EL1], mdscr_el1);
> > write_sysreg(ctxt->gp_regs.regs.sp, sp_el0);
> > }
> >
> > -static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
> > +static void __hyp_text __sysreg_restore_user_state(struct kvm_cpu_context *ctxt)
> > +{
> > + write_sysreg(ctxt->sys_regs[ACTLR_EL1], actlr_el1);
> > + write_sysreg(ctxt->sys_regs[TPIDR_EL0], tpidr_el0);
> > + write_sysreg(ctxt->sys_regs[TPIDRRO_EL0], tpidrro_el0);
> > +}
> > +
> > +static void __hyp_text __sysreg_restore_el1_state(struct kvm_cpu_context *ctxt)
> > {
> > write_sysreg(ctxt->sys_regs[MPIDR_EL1], vmpidr_el2);
> > write_sysreg(ctxt->sys_regs[CSSELR_EL1], csselr_el1);
> > @@ -123,19 +133,21 @@ static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
> > }
> >
> > static hyp_alternate_select(__sysreg_call_restore_host_state,
> > - __sysreg_restore_state, __sysreg_do_nothing,
> > + __sysreg_restore_el1_state, __sysreg_do_nothing,
> > ARM64_HAS_VIRT_HOST_EXTN);
> >
> > void __hyp_text __sysreg_restore_host_state(struct kvm_cpu_context *ctxt)
> > {
> > __sysreg_call_restore_host_state()(ctxt);
> > __sysreg_restore_common_state(ctxt);
> > + __sysreg_restore_user_state(ctxt);
> > }
> >
> > void __hyp_text __sysreg_restore_guest_state(struct kvm_cpu_context *ctxt)
> > {
> > - __sysreg_restore_state(ctxt);
> > + __sysreg_restore_el1_state(ctxt);
> > __sysreg_restore_common_state(ctxt);
> > + __sysreg_restore_user_state(ctxt);
> > }
> >
> > static void __hyp_text __fpsimd32_save_state(struct kvm_cpu_context *ctxt)
> > --
> > 2.9.0
> >
>
> Otherwise
>
> Reviewed-by: Andrew Jones <drjones@xxxxxxxxxx>
Thanks,
-Christoffer
