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

[Christoffer Dall]

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 
> > > Signed-off-by: Christoffer Dall 
> > > ---
> > > 
> > > 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
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Re: [PATCH v4 13/40] KVM: arm64: Introduce VHE-specific kvm_vcpu_run

[Andrew Jones]

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 
> > Signed-off-by: Christoffer Dall 
> > ---
> > 
> > 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()?

Thanks,
drew
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Re: [PATCH v4 13/40] KVM: arm64: Introduce VHE-specific kvm_vcpu_run

[Andrew Jones]

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 
> Signed-off-by: Christoffer Dall 
> ---
> 
> 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);

Thanks,
drew
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