Subject: [PATCH v4 13/40] KVM: arm64: Introduce VHE-specific kvm_vcpu_run

From: [email-masked] (Christoffer Dall)
Date: Thu, 22 Feb 2018 10:16:48 +0100

On Wed, Feb 21, 2018 at 07:18:32PM +0100, Andrew Jones wrote:
> On Wed, Feb 21, 2018 at 06:43:00PM +0100, Andrew Jones wrote:
> > On Thu, Feb 15, 2018 at 10:03:05PM +0100, Christoffer Dall wrote:
> > > So far this is mostly (see below) 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.
> > > 
> > > The only difference after this patch between the VHE and non-VHE run
> > > functions is that we omit the branch-predictor variant-2 hardening for
> > > QC Falkor CPUs, because this workaround is specific to a series of
> > > non-VHE ARMv8.0 CPUs.
> > > 
> > > Reviewed-by: Marc Zyngier <[email-masked]>
> > > Signed-off-by: Christoffer Dall <[email-masked]>
> > > ---
> > > 
> > > Notes:
> > >     Changes since v3:
> > >      - Added BUG() to 32-bit ARM VHE run function
> > >      - Omitted QC Falkor BP Hardening functionality from VHE-specific
> > >        function
> > >     
> > >     Changes since v2:
> > >      - Reworded commit message
> > >     
> > >     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      | 66 +++++++++++++++++++++++++++++++++++++++-
> > >  virt/kvm/arm/arm.c               |  5 ++-
> > >  5 files changed, 77 insertions(+), 5 deletions(-)
> > > 
> > 
> > ...
> > 
> > > diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> > > index 2062d9357971..5bd879c78951 100644
> > > --- a/virt/kvm/arm/arm.c
> > > +++ b/virt/kvm/arm/arm.c
> > > @@ -736,7 +736,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
> > >  		if (has_vhe())
> > >  			kvm_arm_vhe_guest_enter();
> > >  
> > > -		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);
> > >  
> > >  		if (has_vhe())
> > >  			kvm_arm_vhe_guest_exit();
> > 
> > We can combine these has_vhe()'s
> > 
> >  if (has_vhe()) {
> >     kvm_arm_vhe_guest_enter();
> >     ret = kvm_vcpu_run_vhe(vcpu);
> >     kvm_arm_vhe_guest_exit();
> >  } else
> >     ret = kvm_call_hyp(__kvm_vcpu_run_nvhe, vcpu);
> 
> Maybe even do a cleanup patch that removes
> kvm_arm_vhe_guest_enter/exit by putting the daif
> masking/restoring directly into kvm_vcpu_run_vhe()?
> 
Yes, indeed.  This is a blind rebasing result on my part.

Thanks,
-Christoffer