Re: [PATCH v9 1/4] arm: add ARMv7 HYP API to flush VM TLBs, change generic TLB flush to support arch flush

[Mario Smarduch <m.smarduch@samsung.com>]

On 08/11/2014 12:12 PM, Christoffer Dall wrote:
> On Thu, Jul 24, 2014 at 05:56:05PM -0700, Mario Smarduch wrote:
>> Patch adds HYP interface for global VM TLB invalidation without address
>> parameter. Generic VM TLB flush calls ARMv7 arch defined TLB flush function.
>>
>> Signed-off-by: Mario Smarduch <m.smarduch@samsung.com>
>> ---
>>  arch/arm/include/asm/kvm_asm.h  |    1 +
>>  arch/arm/include/asm/kvm_host.h |    1 +
>>  arch/arm/kvm/Kconfig            |    1 +
>>  arch/arm/kvm/interrupts.S       |   12 ++++++++++++
>>  arch/arm/kvm/mmu.c              |   17 +++++++++++++++++
>>  virt/kvm/Kconfig                |    3 +++
>>  virt/kvm/kvm_main.c             |    4 ++++
>>  7 files changed, 39 insertions(+)
>>
>> diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
>> index 53b3c4a..21bc519 100644
>> --- a/arch/arm/include/asm/kvm_asm.h
>> +++ b/arch/arm/include/asm/kvm_asm.h
>> @@ -78,6 +78,7 @@ extern char __kvm_hyp_code_end[];
>>  
>>  extern void __kvm_flush_vm_context(void);
>>  extern void __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa);
>> +extern void __kvm_tlb_flush_vmid(struct kvm *kvm);
>>  
>>  extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
>>  #endif
>> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
>> index 193ceaf..042206f 100644
>> --- a/arch/arm/include/asm/kvm_host.h
>> +++ b/arch/arm/include/asm/kvm_host.h
>> @@ -230,5 +230,6 @@ int kvm_perf_teardown(void);
>>  
>>  u64 kvm_arm_timer_get_reg(struct kvm_vcpu *, u64 regid);
>>  int kvm_arm_timer_set_reg(struct kvm_vcpu *, u64 regid, u64 value);
>> +void kvm_arch_flush_remote_tlbs(struct kvm *);
>>  
>>  #endif /* __ARM_KVM_HOST_H__ */
>> diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
>> index 466bd29..44d3b6f 100644
>> --- a/arch/arm/kvm/Kconfig
>> +++ b/arch/arm/kvm/Kconfig
>> @@ -22,6 +22,7 @@ config KVM
>>  	select ANON_INODES
>>  	select HAVE_KVM_CPU_RELAX_INTERCEPT
>>  	select KVM_MMIO
>> +	select HAVE_KVM_ARCH_TLB_FLUSH_ALL
>>  	select KVM_ARM_HOST
>>  	depends on ARM_VIRT_EXT && ARM_LPAE
>>  	---help---
>> diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S
>> index 0d68d40..1258d46 100644
>> --- a/arch/arm/kvm/interrupts.S
>> +++ b/arch/arm/kvm/interrupts.S
>> @@ -66,6 +66,18 @@ ENTRY(__kvm_tlb_flush_vmid_ipa)
>>  	bx	lr
>>  ENDPROC(__kvm_tlb_flush_vmid_ipa)
>>  
>> +/**
>> + * void __kvm_tlb_flush_vmid(struct kvm *kvm) - Flush per-VMID TLBs
>> + *
>> + * Reuses __kvm_tlb_flush_vmid_ipa() for ARMv7, without passing address
>> + * parameter
>> + */
>> +
>> +ENTRY(__kvm_tlb_flush_vmid)
>> +	b	__kvm_tlb_flush_vmid_ipa
>> +ENDPROC(__kvm_tlb_flush_vmid)
>> +
>> +
>>  /********************************************************************
>>   * Flush TLBs and instruction caches of all CPUs inside the inner-shareable
>>   * domain, for all VMIDs
>> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
>> index 2ac9588..35254c6 100644
>> --- a/arch/arm/kvm/mmu.c
>> +++ b/arch/arm/kvm/mmu.c
>> @@ -56,6 +56,23 @@ static void kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
>>  		kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, kvm, ipa);
>>  }
>>  
>> +#ifdef CONFIG_ARM
> 
> I assume this is here because of arm vs. arm64, use static inlines in
> the header files to differentiate instead.
Yes that's right, will move it.
> 
>> +/**
>> + * kvm_arch_flush_remote_tlbs() - flush all VM TLB entries
>> + * @kvm:       pointer to kvm structure.
>> + *
>> + * Interface to HYP function to flush all VM TLB entries without address
>> + * parameter. In HYP mode reuses __kvm_tlb_flush_vmid_ipa() function used by
>> + * kvm_tlb_flush_vmid_ipa().
> 
> remove the last sentence from here, it's repetitive.
Ok.
> 
>> + */
>> +void kvm_arch_flush_remote_tlbs(struct kvm *kvm)
>> +{
>> +	if (kvm)
>> +		kvm_call_hyp(__kvm_tlb_flush_vmid, kvm);
>> +}
>> +
>> +#endif
>> +
>>  static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
>>  				  int min, int max)
>>  {
>> diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
>> index 13f2d19..f1efaa5 100644
>> --- a/virt/kvm/Kconfig
>> +++ b/virt/kvm/Kconfig
>> @@ -34,3 +34,6 @@ config HAVE_KVM_CPU_RELAX_INTERCEPT
>>  
>>  config KVM_VFIO
>>         bool
>> +
>> +config HAVE_KVM_ARCH_TLB_FLUSH_ALL
>> +       bool
>> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
>> index fa70c6e..258f3d9 100644
>> --- a/virt/kvm/kvm_main.c
>> +++ b/virt/kvm/kvm_main.c
>> @@ -186,12 +186,16 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req)
>>  
>>  void kvm_flush_remote_tlbs(struct kvm *kvm)
>>  {
>> +#ifdef CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL
>> +	kvm_arch_flush_remote_tlbs(kvm);
>> +#else
>>  	long dirty_count = kvm->tlbs_dirty;
>>  
>>  	smp_mb();
>>  	if (make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH))
>>  		++kvm->stat.remote_tlb_flush;
>>  	cmpxchg(&kvm->tlbs_dirty, dirty_count, 0);
>> +#endif
> 
> I would split this into two patches, one trivial one for the KVM generic
> solution, and one to add the arm-specific part.
> 
> That will make your commit text and title much nicer to read too.

Yes makes sense easier to review generic and arch layers.

> 
> Thanks,
> -Christoffer
>