Re: [PATCH v15 10/11] KVM: arm/arm64: Enable Dirty Page logging for ARMv8

[Christoffer Dall <christoffer.dall@linaro.org>]

On Wed, Jan 07, 2015 at 05:51:15PM -0800, Mario Smarduch wrote:
> On 01/07/2015 04:47 AM, Christoffer Dall wrote:
> > On Sun, Dec 14, 2014 at 11:28:07PM -0800, Mario Smarduch wrote:
> >> This patch enables ARMv8 ditry page logging support. Plugs ARMv8 into generic
> > 
> >                            dirty
> yeah.
> > 
> >> layer through Kconfig symbol, and drops earlier ARM64 constraints to enable
> >> logging at architecture layer.
> >>
> >> Signed-off-by: Mario Smarduch <m.smarduch@samsung.com>
> >> ---
> >>  arch/arm/include/asm/kvm_host.h | 12 ------------
> >>  arch/arm/kvm/arm.c              |  4 ----
> >>  arch/arm/kvm/mmu.c              | 19 +++++++++++--------
> >>  arch/arm64/kvm/Kconfig          |  2 ++
> >>  4 files changed, 13 insertions(+), 24 deletions(-)
> >>
> >> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
> >> index b138431..088ea87 100644
> >> --- a/arch/arm/include/asm/kvm_host.h
> >> +++ b/arch/arm/include/asm/kvm_host.h
> >> @@ -223,18 +223,6 @@ static inline void __cpu_init_hyp_mode(phys_addr_t boot_pgd_ptr,
> >>  	kvm_call_hyp((void*)hyp_stack_ptr, vector_ptr, pgd_ptr);
> >>  }
> >>  
> >> -/**
> >> - * kvm_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.
> >> - */
> >> -static inline void kvm_flush_remote_tlbs(struct kvm *kvm)
> >> -{
> >> -	kvm_call_hyp(__kvm_tlb_flush_vmid, kvm);
> >> -}
> >> -
> >>  static inline int kvm_arch_dev_ioctl_check_extension(long ext)
> >>  {
> >>  	return 0;
> >> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
> >> index 6e4290c..1b6577c 100644
> >> --- a/arch/arm/kvm/arm.c
> >> +++ b/arch/arm/kvm/arm.c
> >> @@ -740,7 +740,6 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
> >>   */
> >>  int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
> >>  {
> >> -#ifdef CONFIG_ARM
> >>  	bool is_dirty = false;
> >>  	int r;
> >>  
> >> @@ -753,9 +752,6 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
> >>  
> >>  	mutex_unlock(&kvm->slots_lock);
> >>  	return r;
> >> -#else /* arm64 */
> >> -	return -EINVAL;
> >> -#endif
> >>  }
> >>  
> >>  static int kvm_vm_ioctl_set_device_addr(struct kvm *kvm,
> >> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
> >> index dc763bb..59003df 100644
> >> --- a/arch/arm/kvm/mmu.c
> >> +++ b/arch/arm/kvm/mmu.c
> >> @@ -52,11 +52,18 @@ static phys_addr_t hyp_idmap_vector;
> >>  
> >>  static bool kvm_get_logging_state(struct kvm_memory_slot *memslot)
> >>  {
> >> -#ifdef CONFIG_ARM
> >>  	return !!memslot->dirty_bitmap;
> >> -#else
> >> -	return false;
> >> -#endif
> >> +}
> >> +
> >> +/**
> >> + * kvm_flush_remote_tlbs() - flush all VM TLB entries for v7/8
> >> + * @kvm:	pointer to kvm structure.
> >> + *
> >> + * Interface to HYP function to flush all VM TLB entries
> >> + */
> >> +inline void kvm_flush_remote_tlbs(struct kvm *kvm)
> > 
> > did you intend for a non-staic inline here?
> 
> Yes it's used in arm.c and mmu.c

then why inline?

I'm not a compiler expert by any measure, but poking around I'm pretty
sure the inline keyword in this context is useless.  See for example:
http://www.cs.nyu.edu/~xiaojian/bookmark/c_programming/Inline_Functions.htm

So I suggest either make it a normal stand-alone function or keep it as
duplicate static inlines in the header files if you're adamant about
this being inlined.

-Christoffer