Re: [PATCH v4 08/40] KVM: arm/arm64: Introduce vcpu_el1_is_32bit

[Christoffer Dall]

On Wed, Feb 21, 2018 at 12:05:27PM +, Marc Zyngier wrote:
> On Thu, 15 Feb 2018 21:03:00 +,
> Christoffer Dall wrote:
> > 
> > We have numerous checks around that checks if the HCR_EL2 has the RW bit
> > set to figure out if we're running an AArch64 or AArch32 VM.  In some
> > cases, directly checking the RW bit (given its unintuitive name), is a
> > bit confusing, and that's not going to improve as we move logic around
> > for the following patches that optimize KVM on AArch64 hosts with VHE.
> > 
> > Therefore, introduce a helper, vcpu_el1_is_32bit, and replace existing
> > direct checks of HCR_EL2.RW with the helper.
> > 
> > Reviewed-by: Julien Grall 
> > Reviewed-by: Julien Thierry 
> > Signed-off-by: Christoffer Dall 
> > ---
> > 
> > Notes:
> > Changes since v2:
> >  - New patch
> > 
> > Changes since v1:
> >  - Reworded comments as suggested by Drew
> > 
> >  arch/arm64/include/asm/kvm_emulate.h |  7 ++-
> >  arch/arm64/kvm/hyp/switch.c  | 11 +--
> >  arch/arm64/kvm/hyp/sysreg-sr.c   |  5 +++--
> >  arch/arm64/kvm/inject_fault.c|  6 +++---
> >  4 files changed, 17 insertions(+), 12 deletions(-)
> > 
> > diff --git a/arch/arm64/include/asm/kvm_emulate.h 
> > b/arch/arm64/include/asm/kvm_emulate.h
> > index 9ee316b962c8..3cc535591bdf 100644
> > --- a/arch/arm64/include/asm/kvm_emulate.h
> > +++ b/arch/arm64/include/asm/kvm_emulate.h
> > @@ -45,6 +45,11 @@ void kvm_inject_undef32(struct kvm_vcpu *vcpu);
> >  void kvm_inject_dabt32(struct kvm_vcpu *vcpu, unsigned long addr);
> >  void kvm_inject_pabt32(struct kvm_vcpu *vcpu, unsigned long addr);
> >  
> > +static inline bool vcpu_el1_is_32bit(struct kvm_vcpu *vcpu)
> > +{
> > +   return !(vcpu->arch.hcr_el2 & HCR_RW);
> > +}
> > +
> >  static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu)
> >  {
> > vcpu->arch.hcr_el2 = HCR_GUEST_FLAGS;
> > @@ -65,7 +70,7 @@ static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu)
> >  * For now this is conditional, since no AArch32 feature regs
> >  * are currently virtualised.
> >  */
> > -   if (vcpu->arch.hcr_el2 & HCR_RW)
> > +   if (!vcpu_el1_is_32bit(vcpu))
> > vcpu->arch.hcr_el2 |= HCR_TID3;
> >  }
> >  
> > diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
> > index b51638490d85..fbab9752a9f4 100644
> > --- a/arch/arm64/kvm/hyp/switch.c
> > +++ b/arch/arm64/kvm/hyp/switch.c
> > @@ -74,7 +74,7 @@ static hyp_alternate_select(__activate_traps_arch,
> >  
> >  static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu)
> >  {
> > -   u64 val;
> > +   u64 hcr = vcpu->arch.hcr_el2;
> >  
> > /*
> >  * We are about to set CPTR_EL2.TFP to trap all floating point
> > @@ -85,17 +85,16 @@ static void __hyp_text __activate_traps(struct kvm_vcpu 
> > *vcpu)
> >  * If FP/ASIMD is not implemented, FPEXC is UNDEFINED and any access to
> >  * it will cause an exception.
> >  */
> > -   val = vcpu->arch.hcr_el2;
> > -
> > -   if (!(val & HCR_RW) && system_supports_fpsimd()) {
> > +   if (vcpu_el1_is_32bit(vcpu) && system_supports_fpsimd()) {
> > write_sysreg(1 << 30, fpexc32_el2);
> > isb();
> > }
> > -   write_sysreg(val, hcr_el2);
> >  
> > -   if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN) && (val & HCR_VSE))
> > +   if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN) && (hcr & HCR_VSE))
> > write_sysreg_s(vcpu->arch.vsesr_el2, SYS_VSESR_EL2);
> >  
> > +   write_sysreg(hcr, hcr_el2);
> > +
> > /* Trap on AArch32 cp15 c15 accesses (EL1 or EL0) */
> > write_sysreg(1 << 15, hstr_el2);
> > /*
> > diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
> > index 434f0fc9cfb3..99fc60516103 100644
> > --- a/arch/arm64/kvm/hyp/sysreg-sr.c
> > +++ b/arch/arm64/kvm/hyp/sysreg-sr.c
> > @@ -19,6 +19,7 @@
> >  #include 
> >  
> >  #include 
> > +#include 
> >  #include 
> >  
> >  /* Yes, this does nothing, on purpose */
> > @@ -147,7 +148,7 @@ void __hyp_text __sysreg32_save_state(struct kvm_vcpu 
> > *vcpu)
> >  {
> > u64 *spsr, *sysreg;
> >  
> > -   if (read_sysreg(hcr_el2) & HCR_RW)
> > +   if (!vcpu_el1_is_32bit(vcpu))
> > return;
> >  
> > spsr = vcpu->arch.ctxt.gp_regs.spsr;
> > @@ -172,7 +173,7 @@ void __hyp_text __sysreg32_restore_state(struct 
> > kvm_vcpu *vcpu)
> >  {
> > u64 *spsr, *sysreg;
> >  
> > -   if (read_sysreg(hcr_el2) & HCR_RW)
> > +   if (!vcpu_el1_is_32bit(vcpu))
> > return;
> >  
> > spsr = vcpu->arch.ctxt.gp_regs.spsr;
> > diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c
> > index c1e179d34e6a..30a3f58cdb7b 100644
> > --- a/arch/arm64/kvm/inject_fault.c
> > +++ b/arch/arm64/kvm/inject_fault.c
> > @@ -128,7 +128,7 @@ static void inject_undef64(struct kvm_vcpu *vcpu)
> >   */
> >  void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long addr)
> >  {
> > -   if 

Re: [PATCH v4 08/40] KVM: arm/arm64: Introduce vcpu_el1_is_32bit

[Andrew Jones]

On Thu, Feb 15, 2018 at 10:03:00PM +0100, Christoffer Dall wrote:
> We have numerous checks around that checks if the HCR_EL2 has the RW bit
> set to figure out if we're running an AArch64 or AArch32 VM.  In some
> cases, directly checking the RW bit (given its unintuitive name), is a
> bit confusing, and that's not going to improve as we move logic around
> for the following patches that optimize KVM on AArch64 hosts with VHE.
> 
> Therefore, introduce a helper, vcpu_el1_is_32bit, and replace existing
> direct checks of HCR_EL2.RW with the helper.
> 
> Reviewed-by: Julien Grall 
> Reviewed-by: Julien Thierry 
> Signed-off-by: Christoffer Dall 
> ---
> 
> Notes:
> Changes since v2:
>  - New patch
> 
> Changes since v1:
>  - Reworded comments as suggested by Drew
> 
>  arch/arm64/include/asm/kvm_emulate.h |  7 ++-
>  arch/arm64/kvm/hyp/switch.c  | 11 +--
>  arch/arm64/kvm/hyp/sysreg-sr.c   |  5 +++--
>  arch/arm64/kvm/inject_fault.c|  6 +++---
>  4 files changed, 17 insertions(+), 12 deletions(-)
>

Reviewed-by: Andrew Jones 
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Re: [PATCH v4 08/40] KVM: arm/arm64: Introduce vcpu_el1_is_32bit

[Marc Zyngier]

On Thu, 15 Feb 2018 21:03:00 +,
Christoffer Dall wrote:
> 
> We have numerous checks around that checks if the HCR_EL2 has the RW bit
> set to figure out if we're running an AArch64 or AArch32 VM.  In some
> cases, directly checking the RW bit (given its unintuitive name), is a
> bit confusing, and that's not going to improve as we move logic around
> for the following patches that optimize KVM on AArch64 hosts with VHE.
> 
> Therefore, introduce a helper, vcpu_el1_is_32bit, and replace existing
> direct checks of HCR_EL2.RW with the helper.
> 
> Reviewed-by: Julien Grall 
> Reviewed-by: Julien Thierry 
> Signed-off-by: Christoffer Dall 
> ---
> 
> Notes:
> Changes since v2:
>  - New patch
> 
> Changes since v1:
>  - Reworded comments as suggested by Drew
> 
>  arch/arm64/include/asm/kvm_emulate.h |  7 ++-
>  arch/arm64/kvm/hyp/switch.c  | 11 +--
>  arch/arm64/kvm/hyp/sysreg-sr.c   |  5 +++--
>  arch/arm64/kvm/inject_fault.c|  6 +++---
>  4 files changed, 17 insertions(+), 12 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/kvm_emulate.h 
> b/arch/arm64/include/asm/kvm_emulate.h
> index 9ee316b962c8..3cc535591bdf 100644
> --- a/arch/arm64/include/asm/kvm_emulate.h
> +++ b/arch/arm64/include/asm/kvm_emulate.h
> @@ -45,6 +45,11 @@ void kvm_inject_undef32(struct kvm_vcpu *vcpu);
>  void kvm_inject_dabt32(struct kvm_vcpu *vcpu, unsigned long addr);
>  void kvm_inject_pabt32(struct kvm_vcpu *vcpu, unsigned long addr);
>  
> +static inline bool vcpu_el1_is_32bit(struct kvm_vcpu *vcpu)
> +{
> + return !(vcpu->arch.hcr_el2 & HCR_RW);
> +}
> +
>  static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu)
>  {
>   vcpu->arch.hcr_el2 = HCR_GUEST_FLAGS;
> @@ -65,7 +70,7 @@ static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu)
>* For now this is conditional, since no AArch32 feature regs
>* are currently virtualised.
>*/
> - if (vcpu->arch.hcr_el2 & HCR_RW)
> + if (!vcpu_el1_is_32bit(vcpu))
>   vcpu->arch.hcr_el2 |= HCR_TID3;
>  }
>  
> diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
> index b51638490d85..fbab9752a9f4 100644
> --- a/arch/arm64/kvm/hyp/switch.c
> +++ b/arch/arm64/kvm/hyp/switch.c
> @@ -74,7 +74,7 @@ static hyp_alternate_select(__activate_traps_arch,
>  
>  static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu)
>  {
> - u64 val;
> + u64 hcr = vcpu->arch.hcr_el2;
>  
>   /*
>* We are about to set CPTR_EL2.TFP to trap all floating point
> @@ -85,17 +85,16 @@ static void __hyp_text __activate_traps(struct kvm_vcpu 
> *vcpu)
>* If FP/ASIMD is not implemented, FPEXC is UNDEFINED and any access to
>* it will cause an exception.
>*/
> - val = vcpu->arch.hcr_el2;
> -
> - if (!(val & HCR_RW) && system_supports_fpsimd()) {
> + if (vcpu_el1_is_32bit(vcpu) && system_supports_fpsimd()) {
>   write_sysreg(1 << 30, fpexc32_el2);
>   isb();
>   }
> - write_sysreg(val, hcr_el2);
>  
> - if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN) && (val & HCR_VSE))
> + if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN) && (hcr & HCR_VSE))
>   write_sysreg_s(vcpu->arch.vsesr_el2, SYS_VSESR_EL2);
>  
> + write_sysreg(hcr, hcr_el2);
> +
>   /* Trap on AArch32 cp15 c15 accesses (EL1 or EL0) */
>   write_sysreg(1 << 15, hstr_el2);
>   /*
> diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
> index 434f0fc9cfb3..99fc60516103 100644
> --- a/arch/arm64/kvm/hyp/sysreg-sr.c
> +++ b/arch/arm64/kvm/hyp/sysreg-sr.c
> @@ -19,6 +19,7 @@
>  #include 
>  
>  #include 
> +#include 
>  #include 
>  
>  /* Yes, this does nothing, on purpose */
> @@ -147,7 +148,7 @@ void __hyp_text __sysreg32_save_state(struct kvm_vcpu 
> *vcpu)
>  {
>   u64 *spsr, *sysreg;
>  
> - if (read_sysreg(hcr_el2) & HCR_RW)
> + if (!vcpu_el1_is_32bit(vcpu))
>   return;
>  
>   spsr = vcpu->arch.ctxt.gp_regs.spsr;
> @@ -172,7 +173,7 @@ void __hyp_text __sysreg32_restore_state(struct kvm_vcpu 
> *vcpu)
>  {
>   u64 *spsr, *sysreg;
>  
> - if (read_sysreg(hcr_el2) & HCR_RW)
> + if (!vcpu_el1_is_32bit(vcpu))
>   return;
>  
>   spsr = vcpu->arch.ctxt.gp_regs.spsr;
> diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c
> index c1e179d34e6a..30a3f58cdb7b 100644
> --- a/arch/arm64/kvm/inject_fault.c
> +++ b/arch/arm64/kvm/inject_fault.c
> @@ -128,7 +128,7 @@ static void inject_undef64(struct kvm_vcpu *vcpu)
>   */
>  void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long addr)
>  {
> - if (!(vcpu->arch.hcr_el2 & HCR_RW))
> + if (vcpu_el1_is_32bit(vcpu))
>   kvm_inject_dabt32(vcpu, addr);
>   else
>   inject_abt64(vcpu, false, addr);
> @@ -144,7 +144,7 @@ void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long 
>