Subject: [PATCH v2 11/36] KVM: arm64: Introduce VHE-specific kvm_vcpu_run

From: [email-masked] (Christoffer Dall)
Date: Thu, 14 Dec 2017 13:12:23 +0100

On Mon, Dec 11, 2017 at 09:53:13AM +0000, Marc Zyngier wrote:
> On 07/12/17 17:06, Christoffer Dall wrote:
> > So far this is just a copy of the legacy non-VHE switch function, where
> > we only change the existing calls to has_vhe() in both the original and
> > new functions.
> 
> I'm not sure I correctly parse the above. Do you want to say that you
> use has_vhe() to select the right world switch back-end? Or did you mean
> to drop some of the has_vhe() calls in the non-VHE case?
> 

That's a leftover from a previous patch version.  How about the
following instead?

  So far this is just a copy of the legacy non-VHE switch function, but we
  will start reworking these functions in separate directions to work on
  VHE and non-VHE in the most optimal way in later patches.

Thanks,
-Christoffer

> > 
> > Signed-off-by: Christoffer Dall <[email-masked]>
> > ---
> > 
> > Notes:
> >     Changes since v1:
> >      - Rename kvm_vcpu_run to kvm_vcpu_run_vhe and rename __kvm_vcpu_run to
> >        __kvm_vcpu_run_nvhe
> >      - Removed stray whitespace line
> > 
> >  arch/arm/include/asm/kvm_asm.h   |  5 +++-
> >  arch/arm/kvm/hyp/switch.c        |  2 +-
> >  arch/arm64/include/asm/kvm_asm.h |  4 ++-
> >  arch/arm64/kvm/hyp/switch.c      | 58 +++++++++++++++++++++++++++++++++++++++-
> >  virt/kvm/arm/arm.c               |  5 +++-
> >  5 files changed, 69 insertions(+), 5 deletions(-)
> > 
> > diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
> > index 36dd2962a42d..4ac717276543 100644
> > --- a/arch/arm/include/asm/kvm_asm.h
> > +++ b/arch/arm/include/asm/kvm_asm.h
> > @@ -70,7 +70,10 @@ extern void __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu);
> >  
> >  extern void __kvm_timer_set_cntvoff(u32 cntvoff_low, u32 cntvoff_high);
> >  
> > -extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
> > +/* no VHE on 32-bit :( */
> > +static inline int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu) { return 0; }
> > +
> > +extern int __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu);
> >  
> >  extern void __init_stage2_translation(void);
> >  
> > diff --git a/arch/arm/kvm/hyp/switch.c b/arch/arm/kvm/hyp/switch.c
> > index c3b9799e2e13..7b2bd25e3b10 100644
> > --- a/arch/arm/kvm/hyp/switch.c
> > +++ b/arch/arm/kvm/hyp/switch.c
> > @@ -153,7 +153,7 @@ static bool __hyp_text __populate_fault_info(struct kvm_vcpu *vcpu)
> >  	return true;
> >  }
> >  
> > -int __hyp_text __kvm_vcpu_run(struct kvm_vcpu *vcpu)
> > +int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
> >  {
> >  	struct kvm_cpu_context *host_ctxt;
> >  	struct kvm_cpu_context *guest_ctxt;
> > diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> > index 33e0edc6f8be..adaf1db12271 100644
> > --- a/arch/arm64/include/asm/kvm_asm.h
> > +++ b/arch/arm64/include/asm/kvm_asm.h
> > @@ -58,7 +58,9 @@ extern void __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu);
> >  
> >  extern void __kvm_timer_set_cntvoff(u32 cntvoff_low, u32 cntvoff_high);
> >  
> > -extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
> > +extern int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu);
> > +
> > +extern int __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu);
> >  
> >  extern u64 __vgic_v3_get_ich_vtr_el2(void);
> >  extern u64 __vgic_v3_read_vmcr(void);
> > diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
> > index 845e3bece399..8f32f8dcab65 100644
> > --- a/arch/arm64/kvm/hyp/switch.c
> > +++ b/arch/arm64/kvm/hyp/switch.c
> > @@ -342,7 +342,63 @@ static bool __hyp_text fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code)
> >  	return false;
> >  }
> >  
> > -int __hyp_text __kvm_vcpu_run(struct kvm_vcpu *vcpu)
> > +/* Switch to the guest for VHE systems running in EL2 */
> > +int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
> > +{
> > +	struct kvm_cpu_context *host_ctxt;
> > +	struct kvm_cpu_context *guest_ctxt;
> > +	u64 exit_code;
> > +
> > +	vcpu = kern_hyp_va(vcpu);
> > +
> > +	host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
> > +	host_ctxt->__hyp_running_vcpu = vcpu;
> > +	guest_ctxt = &vcpu->arch.ctxt;
> > +
> > +	__sysreg_save_host_state(host_ctxt);
> > +
> > +	__activate_traps(vcpu);
> > +	__activate_vm(vcpu);
> > +
> > +	__vgic_restore_state(vcpu);
> > +	__timer_enable_traps(vcpu);
> > +
> > +	/*
> > +	 * We must restore the 32-bit state before the sysregs, thanks
> > +	 * to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).
> > +	 */
> > +	__sysreg32_restore_state(vcpu);
> > +	__sysreg_restore_guest_state(guest_ctxt);
> > +	__debug_switch_to_guest(vcpu);
> > +
> > +	do {
> > +		/* Jump in the fire! */
> > +		exit_code = __guest_enter(vcpu, host_ctxt);
> > +
> > +		/* And we're baaack! */
> > +	} while (fixup_guest_exit(vcpu, &exit_code));
> > +
> > +	__sysreg_save_guest_state(guest_ctxt);
> > +	__sysreg32_save_state(vcpu);
> > +	__timer_disable_traps(vcpu);
> > +	__vgic_save_state(vcpu);
> > +
> > +	__deactivate_traps(vcpu);
> > +	__deactivate_vm(vcpu);
> > +
> > +	__sysreg_restore_host_state(host_ctxt);
> > +
> > +	/*
> > +	 * This must come after restoring the host sysregs, since a non-VHE
> > +	 * system may enable SPE here and make use of the TTBRs.
> > +	 */
> > +	__debug_switch_to_host(vcpu);
> > +
> > +	return exit_code;
> > +}
> > +
> > +/* Switch to the guest for legacy non-VHE systems */
> > +int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
> >  {
> >  	struct kvm_cpu_context *host_ctxt;
> >  	struct kvm_cpu_context *guest_ctxt;
> > diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> > index 3e10343374a1..104ee524c75a 100644
> > --- a/virt/kvm/arm/arm.c
> > +++ b/virt/kvm/arm/arm.c
> > @@ -712,7 +712,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
> >  		trace_kvm_entry(*vcpu_pc(vcpu));
> >  		guest_enter_irqoff();
> >  
> > -		ret = kvm_call_hyp(__kvm_vcpu_run, vcpu);
> > +		if (has_vhe())
> > +			ret = kvm_vcpu_run_vhe(vcpu);
> > +		else
> > +			ret = kvm_call_hyp(__kvm_vcpu_run_nvhe, vcpu);
> >  
> >  		vcpu->mode = OUTSIDE_GUEST_MODE;
> >  		vcpu->stat.exits++;
> > 
> 
> Otherwise looks good to me.
> 
> 	M.
> -- 
> Jazz is not dead. It just smells funny...