Re: [PATCH 3/4] KVM: arm64: Convert the host S2 over to __load_guest_stage2()

[Marc Zyngier <maz@kernel.org>]

On Fri, 06 Aug 2021 14:40:00 +0100,
Quentin Perret <qperret@google.com> wrote:
> 
> On Friday 06 Aug 2021 at 12:31:07 (+0100), Will Deacon wrote:
> > From: Marc Zyngier <maz@kernel.org>
> > 
> > The protected mode relies on a separate helper to load the
> > S2 context. Move over to the __load_guest_stage2() helper
> > instead.
> > 
> > Cc: Catalin Marinas <catalin.marinas@arm.com>
> > Cc: Jade Alglave <jade.alglave@arm.com>
> > Cc: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> > Signed-off-by: Marc Zyngier <maz@kernel.org>
> > Signed-off-by: Will Deacon <will@kernel.org>
> > ---
> >  arch/arm64/include/asm/kvm_mmu.h              | 11 +++--------
> >  arch/arm64/kvm/hyp/include/nvhe/mem_protect.h |  2 +-
> >  arch/arm64/kvm/hyp/nvhe/mem_protect.c         |  2 +-
> >  3 files changed, 5 insertions(+), 10 deletions(-)
> > 
> > diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
> > index 05e089653a1a..934ef0deff9f 100644
> > --- a/arch/arm64/include/asm/kvm_mmu.h
> > +++ b/arch/arm64/include/asm/kvm_mmu.h
> > @@ -267,9 +267,10 @@ static __always_inline u64 kvm_get_vttbr(struct kvm_s2_mmu *mmu)
> >   * Must be called from hyp code running at EL2 with an updated VTTBR
> >   * and interrupts disabled.
> >   */
> > -static __always_inline void __load_stage2(struct kvm_s2_mmu *mmu, unsigned long vtcr)
> > +static __always_inline void __load_guest_stage2(struct kvm_s2_mmu *mmu,
> > +						struct kvm_arch *arch)
> >  {
> > -	write_sysreg(vtcr, vtcr_el2);
> > +	write_sysreg(arch->vtcr, vtcr_el2);
> >  	write_sysreg(kvm_get_vttbr(mmu), vttbr_el2);
> >  
> >  	/*
> > @@ -280,12 +281,6 @@ static __always_inline void __load_stage2(struct kvm_s2_mmu *mmu, unsigned long
> >  	asm(ALTERNATIVE("nop", "isb", ARM64_WORKAROUND_SPECULATIVE_AT));
> >  }
> >  
> > -static __always_inline void __load_guest_stage2(struct kvm_s2_mmu *mmu,
> > -						struct kvm_arch *arch)
> > -{
> > -	__load_stage2(mmu, arch->vtcr);
> > -}
> > -
> >  static inline struct kvm *kvm_s2_mmu_to_kvm(struct kvm_s2_mmu *mmu)
> >  {
> >  	return container_of(mmu->arch, struct kvm, arch);
> > diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
> > index 9c227d87c36d..a910648bc71b 100644
> > --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
> > +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
> > @@ -29,7 +29,7 @@ void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt);
> >  static __always_inline void __load_host_stage2(void)
> >  {
> >  	if (static_branch_likely(&kvm_protected_mode_initialized))
> > -		__load_stage2(&host_kvm.arch.mmu, host_kvm.arch.vtcr);
> > +		__load_guest_stage2(&host_kvm.arch.mmu, &host_kvm.arch);
> >  	else
> >  		write_sysreg(0, vttbr_el2);
> >  }
> > diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> > index d938ce95d3bd..d4e74ca7f876 100644
> > --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> > +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> > @@ -126,7 +126,7 @@ int __pkvm_prot_finalize(void)
> >  	kvm_flush_dcache_to_poc(params, sizeof(*params));
> >  
> >  	write_sysreg(params->hcr_el2, hcr_el2);
> > -	__load_stage2(&host_kvm.arch.mmu, host_kvm.arch.vtcr);
> > +	__load_guest_stage2(&host_kvm.arch.mmu, &host_kvm.arch);
> 
> Nit: clearly we're not loading a guest stage-2 here, so maybe the
> function should take a more generic name?

How about we rename __load_guest_stage2() to __load_stage2() instead,
with the same parameters?

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.
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