Re: [PATCH v4 04/13] nEPT: Move common code to paging_tmpl.h

[Gleb Natapov <gleb@redhat.com>]

On Wed, Jul 31, 2013 at 04:02:49PM +0800, Xiao Guangrong wrote:
> On 07/25/2013 06:59 PM, Gleb Natapov wrote:
> > From: Nadav Har'El <nyh@il.ibm.com>
> > 
> > For preparation, we just move gpte_access(), prefetch_invalid_gpte(),
> > s_rsvd_bits_set(), protect_clean_gpte() and is_dirty_gpte() from mmu.c
> > to paging_tmpl.h.
> > 
> > Signed-off-by: Nadav Har'El <nyh@il.ibm.com>
> > Signed-off-by: Jun Nakajima <jun.nakajima@intel.com>
> > Signed-off-by: Xinhao Xu <xinhao.xu@intel.com>
> > Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
> > Signed-off-by: Jun Nakajima <jun.nakajima@intel.com>
> > Signed-off-by: Gleb Natapov <gleb@redhat.com>
> > ---
> >  arch/x86/kvm/mmu.c         |   55 ------------------------------
> >  arch/x86/kvm/paging_tmpl.h |   80 +++++++++++++++++++++++++++++++++++++-------
> >  2 files changed, 68 insertions(+), 67 deletions(-)
> > 
> > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> > index 3a9493a..4c4274d 100644
> > --- a/arch/x86/kvm/mmu.c
> > +++ b/arch/x86/kvm/mmu.c
> > @@ -331,11 +331,6 @@ static int is_large_pte(u64 pte)
> >  	return pte & PT_PAGE_SIZE_MASK;
> >  }
> > 
> > -static int is_dirty_gpte(unsigned long pte)
> > -{
> > -	return pte & PT_DIRTY_MASK;
> > -}
> > -
> >  static int is_rmap_spte(u64 pte)
> >  {
> >  	return is_shadow_present_pte(pte);
> > @@ -2574,14 +2569,6 @@ static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
> >  	mmu_free_roots(vcpu);
> >  }
> > 
> > -static bool is_rsvd_bits_set(struct kvm_mmu *mmu, u64 gpte, int level)
> > -{
> > -	int bit7;
> > -
> > -	bit7 = (gpte >> 7) & 1;
> > -	return (gpte & mmu->rsvd_bits_mask[bit7][level-1]) != 0;
> > -}
> > -
> >  static pfn_t pte_prefetch_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn,
> >  				     bool no_dirty_log)
> >  {
> > @@ -2594,26 +2581,6 @@ static pfn_t pte_prefetch_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn,
> >  	return gfn_to_pfn_memslot_atomic(slot, gfn);
> >  }
> > 
> > -static bool prefetch_invalid_gpte(struct kvm_vcpu *vcpu,
> > -				  struct kvm_mmu_page *sp, u64 *spte,
> > -				  u64 gpte)
> > -{
> > -	if (is_rsvd_bits_set(&vcpu->arch.mmu, gpte, PT_PAGE_TABLE_LEVEL))
> > -		goto no_present;
> > -
> > -	if (!is_present_gpte(gpte))
> > -		goto no_present;
> > -
> > -	if (!(gpte & PT_ACCESSED_MASK))
> > -		goto no_present;
> > -
> > -	return false;
> > -
> > -no_present:
> > -	drop_spte(vcpu->kvm, spte);
> > -	return true;
> > -}
> > -
> >  static int direct_pte_prefetch_many(struct kvm_vcpu *vcpu,
> >  				    struct kvm_mmu_page *sp,
> >  				    u64 *start, u64 *end)
> > @@ -3501,18 +3468,6 @@ static void paging_free(struct kvm_vcpu *vcpu)
> >  	nonpaging_free(vcpu);
> >  }
> > 
> > -static inline void protect_clean_gpte(unsigned *access, unsigned gpte)
> > -{
> > -	unsigned mask;
> > -
> > -	BUILD_BUG_ON(PT_WRITABLE_MASK != ACC_WRITE_MASK);
> > -
> > -	mask = (unsigned)~ACC_WRITE_MASK;
> > -	/* Allow write access to dirty gptes */
> > -	mask |= (gpte >> (PT_DIRTY_SHIFT - PT_WRITABLE_SHIFT)) & PT_WRITABLE_MASK;
> > -	*access &= mask;
> > -}
> > -
> >  static bool sync_mmio_spte(struct kvm *kvm, u64 *sptep, gfn_t gfn,
> >  			   unsigned access, int *nr_present)
> >  {
> > @@ -3530,16 +3485,6 @@ static bool sync_mmio_spte(struct kvm *kvm, u64 *sptep, gfn_t gfn,
> >  	return false;
> >  }
> > 
> > -static inline unsigned gpte_access(struct kvm_vcpu *vcpu, u64 gpte)
> > -{
> > -	unsigned access;
> > -
> > -	access = (gpte & (PT_WRITABLE_MASK | PT_USER_MASK)) | ACC_EXEC_MASK;
> > -	access &= ~(gpte >> PT64_NX_SHIFT);
> > -
> > -	return access;
> > -}
> > -
> >  static inline bool is_last_gpte(struct kvm_mmu *mmu, unsigned level, unsigned gpte)
> >  {
> >  	unsigned index;
> > diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
> > index 7769699..fb26ca9 100644
> > --- a/arch/x86/kvm/paging_tmpl.h
> > +++ b/arch/x86/kvm/paging_tmpl.h
> > @@ -80,6 +80,31 @@ static gfn_t gpte_to_gfn_lvl(pt_element_t gpte, int lvl)
> >  	return (gpte & PT_LVL_ADDR_MASK(lvl)) >> PAGE_SHIFT;
> >  }
> > 
> > +static inline void FNAME(protect_clean_gpte)(unsigned *access, unsigned gpte)
> > +{
> > +	unsigned mask;
> > +
> > +	BUILD_BUG_ON(PT_WRITABLE_MASK != ACC_WRITE_MASK);
> > +
> > +	mask = (unsigned)~ACC_WRITE_MASK;
> > +	/* Allow write access to dirty gptes */
> > +	mask |= (gpte >> (PT_DIRTY_SHIFT - PT_WRITABLE_SHIFT)) & PT_WRITABLE_MASK;
> > +	*access &= mask;
> > +}
> > +
> > +static bool FNAME(is_rsvd_bits_set)(struct kvm_mmu *mmu, u64 gpte, int level)
> > +{
> > +	int bit7;
> > +
> > +	bit7 = (gpte >> 7) & 1;
> > +	return (gpte & mmu->rsvd_bits_mask[bit7][level-1]) != 0;
> > +}
> > +
> > +static inline int FNAME(is_present_gpte)(unsigned long pte)
> > +{
> > +	return is_present_gpte(pte);
> > +}
> 
> It is adding a new function not just move and failed to mention it in the
> change log. :)
> 
> > +
> >  static int FNAME(cmpxchg_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
> >  			       pt_element_t __user *ptep_user, unsigned index,
> >  			       pt_element_t orig_pte, pt_element_t new_pte)
> > @@ -103,6 +128,36 @@ static int FNAME(cmpxchg_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
> >  	return (ret != orig_pte);
> >  }
> > 
> > +static bool FNAME(prefetch_invalid_gpte)(struct kvm_vcpu *vcpu,
> > +				  struct kvm_mmu_page *sp, u64 *spte,
> > +				  u64 gpte)
> > +{
> > +	if (FNAME(is_rsvd_bits_set)(&vcpu->arch.mmu, gpte, PT_PAGE_TABLE_LEVEL))
> > +		goto no_present;
> > +
> > +	if (!FNAME(is_present_gpte)(gpte))
> > +		goto no_present;
> > +
> > +	if (!(gpte & PT_ACCESSED_MASK))
> > +		goto no_present;
> > +
> > +	return false;
> > +
> > +no_present:
> > +	drop_spte(vcpu->kvm, spte);
> > +	return true;
> > +}
> > +
> > +static inline unsigned FNAME(gpte_access)(struct kvm_vcpu *vcpu, u64 gpte)
> > +{
> > +	unsigned access;
> > +
> > +	access = (gpte & (PT_WRITABLE_MASK | PT_USER_MASK)) | ACC_EXEC_MASK;
> > +	access &= ~(gpte >> PT64_NX_SHIFT);
> > +
> > +	return access;
> > +}
> > +
> >  static int FNAME(update_accessed_dirty_bits)(struct kvm_vcpu *vcpu,
> >  					     struct kvm_mmu *mmu,
> >  					     struct guest_walker *walker,
> > @@ -123,7 +178,8 @@ static int FNAME(update_accessed_dirty_bits)(struct kvm_vcpu *vcpu,
> >  			trace_kvm_mmu_set_accessed_bit(table_gfn, index, sizeof(pte));
> >  			pte |= PT_ACCESSED_MASK;
> >  		}
> > -		if (level == walker->level && write_fault && !is_dirty_gpte(pte)) {
> > +		if (level == walker->level && write_fault &&
> > +				!(pte & PT_DIRTY_MASK)) {
> 
> Why use the raw code instead of the function? Since it is the only user of
> this function, so drop the function?
> 
Yes, I have two choses either move the function to paging_tmpl.h and
make it FNAME(is_dirty_gpte)() or just drop it since other bits we check
in pte are open coded anyway. Dropping function seems more consistent
with the rest of the code.


> Others look good to me.
> 
> Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>

--
			Gleb.