Re: [PATCH v3 11/23] arm64: KVM: VHE: Split save/restore of registers shared between guest and host

[Christoffer Dall]

On Wed, Feb 03, 2016 at 06:00:04PM +0000, Marc Zyngier wrote:
> A handful of system registers are still shared between host and guest,
> even while using VHE (tpidr*_el[01] and actlr_el1).
> 
> Also, some of the vcpu state (sp_el0, PC and PSTATE) must be
> save/restored on entry/exit, as they are used on the host as well.
> 
> In order to facilitate the introduction of a VHE-specific sysreg
> save/restore, make move the access to these registers to their
> own save/restore functions.
> 
> No functionnal change.

uber nit: s/functionnal/functional/

> 
> Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
> ---
>  arch/arm64/kvm/hyp/sysreg-sr.c | 48 +++++++++++++++++++++++++++++-------------
>  1 file changed, 33 insertions(+), 15 deletions(-)
> 
> diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
> index bd5b543..61bad17 100644
> --- a/arch/arm64/kvm/hyp/sysreg-sr.c
> +++ b/arch/arm64/kvm/hyp/sysreg-sr.c
> @@ -23,13 +23,29 @@
>  
>  #include "hyp.h"
>  
> -/* ctxt is already in the HYP VA space */
> +/*
> + * Non-VHE: Both host and guest must save everything.
> + *
> + * VHE: Host must save tpidr*_el[01], actlr_el1, sp0, pc, pstate, and
> + * guest must save everything.
> + */
> +
> +static void __hyp_text __sysreg_save_common_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[TPIDR_EL1]	= read_sysreg(tpidr_el1);
> +	ctxt->gp_regs.regs.sp		= read_sysreg(sp_el0);
> +	ctxt->gp_regs.regs.pc		= read_sysreg(elr_el2);
> +	ctxt->gp_regs.regs.pstate	= read_sysreg(spsr_el2);
> +}
> +
>  static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
>  {
>  	ctxt->sys_regs[MPIDR_EL1]	= read_sysreg(vmpidr_el2);
>  	ctxt->sys_regs[CSSELR_EL1]	= read_sysreg(csselr_el1);
>  	ctxt->sys_regs[SCTLR_EL1]	= read_sysreg(sctlr_el1);
> -	ctxt->sys_regs[ACTLR_EL1]	= read_sysreg(actlr_el1);
>  	ctxt->sys_regs[CPACR_EL1]	= read_sysreg(cpacr_el1);
>  	ctxt->sys_regs[TTBR0_EL1]	= read_sysreg(ttbr0_el1);
>  	ctxt->sys_regs[TTBR1_EL1]	= read_sysreg(ttbr1_el1);
> @@ -41,17 +57,11 @@ static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
>  	ctxt->sys_regs[MAIR_EL1]	= read_sysreg(mair_el1);
>  	ctxt->sys_regs[VBAR_EL1]	= read_sysreg(vbar_el1);
>  	ctxt->sys_regs[CONTEXTIDR_EL1]	= read_sysreg(contextidr_el1);
> -	ctxt->sys_regs[TPIDR_EL0]	= read_sysreg(tpidr_el0);
> -	ctxt->sys_regs[TPIDRRO_EL0]	= read_sysreg(tpidrro_el0);
> -	ctxt->sys_regs[TPIDR_EL1]	= read_sysreg(tpidr_el1);
>  	ctxt->sys_regs[AMAIR_EL1]	= read_sysreg(amair_el1);
>  	ctxt->sys_regs[CNTKCTL_EL1]	= read_sysreg(cntkctl_el1);
>  	ctxt->sys_regs[PAR_EL1]		= read_sysreg(par_el1);
>  	ctxt->sys_regs[MDSCR_EL1]	= read_sysreg(mdscr_el1);
>  
> -	ctxt->gp_regs.regs.sp		= read_sysreg(sp_el0);
> -	ctxt->gp_regs.regs.pc		= read_sysreg(elr_el2);
> -	ctxt->gp_regs.regs.pstate	= read_sysreg(spsr_el2);
>  	ctxt->gp_regs.sp_el1		= read_sysreg(sp_el1);
>  	ctxt->gp_regs.elr_el1		= read_sysreg(elr_el1);
>  	ctxt->gp_regs.spsr[KVM_SPSR_EL1]= read_sysreg(spsr_el1);
> @@ -60,11 +70,24 @@ static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
>  void __hyp_text __sysreg_save_host_state(struct kvm_cpu_context *ctxt)
>  {
>  	__sysreg_save_state(ctxt);
> +	__sysreg_save_common_state(ctxt);
>  }
>  
>  void __hyp_text __sysreg_save_guest_state(struct kvm_cpu_context *ctxt)
>  {
>  	__sysreg_save_state(ctxt);
> +	__sysreg_save_common_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[TPIDR_EL1],	  tpidr_el1);
> +	write_sysreg(ctxt->gp_regs.regs.sp,	  sp_el0);
> +	write_sysreg(ctxt->gp_regs.regs.pc,	  elr_el2);
> +	write_sysreg(ctxt->gp_regs.regs.pstate,	  spsr_el2);
>  }
>  
>  static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
> @@ -72,7 +95,6 @@ static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
>  	write_sysreg(ctxt->sys_regs[MPIDR_EL1],	  vmpidr_el2);
>  	write_sysreg(ctxt->sys_regs[CSSELR_EL1],  csselr_el1);
>  	write_sysreg(ctxt->sys_regs[SCTLR_EL1],	  sctlr_el1);
> -	write_sysreg(ctxt->sys_regs[ACTLR_EL1],	  actlr_el1);
>  	write_sysreg(ctxt->sys_regs[CPACR_EL1],	  cpacr_el1);
>  	write_sysreg(ctxt->sys_regs[TTBR0_EL1],	  ttbr0_el1);
>  	write_sysreg(ctxt->sys_regs[TTBR1_EL1],	  ttbr1_el1);
> @@ -84,17 +106,11 @@ static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
>  	write_sysreg(ctxt->sys_regs[MAIR_EL1],	  mair_el1);
>  	write_sysreg(ctxt->sys_regs[VBAR_EL1],	  vbar_el1);
>  	write_sysreg(ctxt->sys_regs[CONTEXTIDR_EL1], contextidr_el1);
> -	write_sysreg(ctxt->sys_regs[TPIDR_EL0],	  tpidr_el0);
> -	write_sysreg(ctxt->sys_regs[TPIDRRO_EL0], tpidrro_el0);
> -	write_sysreg(ctxt->sys_regs[TPIDR_EL1],	  tpidr_el1);
>  	write_sysreg(ctxt->sys_regs[AMAIR_EL1],	  amair_el1);
>  	write_sysreg(ctxt->sys_regs[CNTKCTL_EL1], cntkctl_el1);
>  	write_sysreg(ctxt->sys_regs[PAR_EL1],	  par_el1);
>  	write_sysreg(ctxt->sys_regs[MDSCR_EL1],	  mdscr_el1);
>  
> -	write_sysreg(ctxt->gp_regs.regs.sp,	sp_el0);
> -	write_sysreg(ctxt->gp_regs.regs.pc,	elr_el2);
> -	write_sysreg(ctxt->gp_regs.regs.pstate,	spsr_el2);
>  	write_sysreg(ctxt->gp_regs.sp_el1,	sp_el1);
>  	write_sysreg(ctxt->gp_regs.elr_el1,	elr_el1);
>  	write_sysreg(ctxt->gp_regs.spsr[KVM_SPSR_EL1], spsr_el1);
> @@ -103,11 +119,13 @@ static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
>  void __hyp_text __sysreg_restore_host_state(struct kvm_cpu_context *ctxt)
>  {
>  	__sysreg_restore_state(ctxt);
> +	__sysreg_restore_common_state(ctxt);
>  }
>  
>  void __hyp_text __sysreg_restore_guest_state(struct kvm_cpu_context *ctxt)
>  {
>  	__sysreg_restore_state(ctxt);
> +	__sysreg_restore_common_state(ctxt);
>  }
>  
>  void __hyp_text __sysreg32_save_state(struct kvm_vcpu *vcpu)
> -- 
> 2.1.4
>