Patchwork [6/6,v2] kvm: powerpc: use caching attributes as per linux pte

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Submitter Bharat Bhushan
Date Aug. 1, 2013, 11:12 a.m.
Message ID <1375355558-19187-7-git-send-email-Bharat.Bhushan@freescale.com>
Download mbox | patch
Permalink /patch/263973/
State New
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Comments

Bharat Bhushan - Aug. 1, 2013, 11:12 a.m.
KVM uses same WIM tlb attributes as the corresponding qemu pte.
For this we now search the linux pte for the requested page and
get these cache caching/coherency attributes from pte.

Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
---
v1->v2
 - Use Linux pte for wimge rather than RAM/no-RAM mechanism

 arch/powerpc/include/asm/kvm_host.h |    2 +-
 arch/powerpc/kvm/booke.c            |    2 +-
 arch/powerpc/kvm/e500.h             |    8 +++++---
 arch/powerpc/kvm/e500_mmu_host.c    |   31 ++++++++++++++++++-------------
 4 files changed, 25 insertions(+), 18 deletions(-)
Tiejun Chen - Aug. 2, 2013, 6:24 a.m.
On 08/01/2013 07:12 PM, Bharat Bhushan wrote:
> KVM uses same WIM tlb attributes as the corresponding qemu pte.
> For this we now search the linux pte for the requested page and
> get these cache caching/coherency attributes from pte.
>
> Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
> ---
> v1->v2
>   - Use Linux pte for wimge rather than RAM/no-RAM mechanism
>
>   arch/powerpc/include/asm/kvm_host.h |    2 +-
>   arch/powerpc/kvm/booke.c            |    2 +-
>   arch/powerpc/kvm/e500.h             |    8 +++++---
>   arch/powerpc/kvm/e500_mmu_host.c    |   31 ++++++++++++++++++-------------
>   4 files changed, 25 insertions(+), 18 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
> index 3328353..583d405 100644
> --- a/arch/powerpc/include/asm/kvm_host.h
> +++ b/arch/powerpc/include/asm/kvm_host.h
> @@ -535,6 +535,7 @@ struct kvm_vcpu_arch {
>   #endif
>   	gpa_t paddr_accessed;
>   	gva_t vaddr_accessed;
> +	pgd_t *pgdir;
>
>   	u8 io_gpr; /* GPR used as IO source/target */
>   	u8 mmio_is_bigendian;
> @@ -592,7 +593,6 @@ struct kvm_vcpu_arch {
>   	struct list_head run_list;
>   	struct task_struct *run_task;
>   	struct kvm_run *kvm_run;
> -	pgd_t *pgdir;
>
>   	spinlock_t vpa_update_lock;
>   	struct kvmppc_vpa vpa;
> diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
> index 17722d8..ebcccc2 100644
> --- a/arch/powerpc/kvm/booke.c
> +++ b/arch/powerpc/kvm/booke.c
> @@ -697,7 +697,7 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
>   #endif
>
>   	kvmppc_fix_ee_before_entry();
> -
> +	vcpu->arch.pgdir = current->mm->pgd;
>   	ret = __kvmppc_vcpu_run(kvm_run, vcpu);
>
>   	/* No need for kvm_guest_exit. It's done in handle_exit.
> diff --git a/arch/powerpc/kvm/e500.h b/arch/powerpc/kvm/e500.h
> index 4fd9650..fc4b2f6 100644
> --- a/arch/powerpc/kvm/e500.h
> +++ b/arch/powerpc/kvm/e500.h
> @@ -31,11 +31,13 @@ enum vcpu_ftr {
>   #define E500_TLB_NUM   2
>
>   /* entry is mapped somewhere in host TLB */
> -#define E500_TLB_VALID		(1 << 0)
> +#define E500_TLB_VALID		(1 << 31)
>   /* TLB1 entry is mapped by host TLB1, tracked by bitmaps */
> -#define E500_TLB_BITMAP		(1 << 1)
> +#define E500_TLB_BITMAP		(1 << 30)
>   /* TLB1 entry is mapped by host TLB0 */
> -#define E500_TLB_TLB0		(1 << 2)
> +#define E500_TLB_TLB0		(1 << 29)
> +/* Lower 5 bits have WIMGE value */
> +#define E500_TLB_WIMGE_MASK	(0x1f)
>
>   struct tlbe_ref {
>   	pfn_t pfn;		/* valid only for TLB0, except briefly */
> diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c
> index 1c6a9d7..9b10b0b 100644
> --- a/arch/powerpc/kvm/e500_mmu_host.c
> +++ b/arch/powerpc/kvm/e500_mmu_host.c
> @@ -64,15 +64,6 @@ static inline u32 e500_shadow_mas3_attrib(u32 mas3, int usermode)
>   	return mas3;
>   }
>
> -static inline u32 e500_shadow_mas2_attrib(u32 mas2, int usermode)
> -{
> -#ifdef CONFIG_SMP
> -	return (mas2 & MAS2_ATTRIB_MASK) | MAS2_M;
> -#else
> -	return mas2 & MAS2_ATTRIB_MASK;
> -#endif
> -}
> -
>   /*
>    * writing shadow tlb entry to host TLB
>    */
> @@ -248,10 +239,12 @@ static inline int tlbe_is_writable(struct kvm_book3e_206_tlb_entry *tlbe)
>
>   static inline void kvmppc_e500_ref_setup(struct tlbe_ref *ref,
>   					 struct kvm_book3e_206_tlb_entry *gtlbe,
> -					 pfn_t pfn)
> +					 pfn_t pfn, int wimg)
>   {
>   	ref->pfn = pfn;
>   	ref->flags |= E500_TLB_VALID;
> +	/* Use guest supplied MAS2_G and MAS2_E */
> +	ref->flags |= (gtlbe->mas2 & MAS2_ATTRIB_MASK) | wimg;
>
>   	if (tlbe_is_writable(gtlbe))
>   		kvm_set_pfn_dirty(pfn);
> @@ -312,8 +305,7 @@ static void kvmppc_e500_setup_stlbe(
>
>   	/* Force IPROT=0 for all guest mappings. */
>   	stlbe->mas1 = MAS1_TSIZE(tsize) | get_tlb_sts(gtlbe) | MAS1_VALID;
> -	stlbe->mas2 = (gvaddr & MAS2_EPN) |
> -		      e500_shadow_mas2_attrib(gtlbe->mas2, pr);
> +	stlbe->mas2 = (gvaddr & MAS2_EPN) | (ref->flags & E500_TLB_WIMGE_MASK);
>   	stlbe->mas7_3 = ((u64)pfn << PAGE_SHIFT) |
>   			e500_shadow_mas3_attrib(gtlbe->mas7_3, pr);
>
> @@ -332,6 +324,8 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
>   	unsigned long hva;
>   	int pfnmap = 0;
>   	int tsize = BOOK3E_PAGESZ_4K;
> +	pte_t pte;
> +	int wimg = 0;
>
>   	/*
>   	 * Translate guest physical to true physical, acquiring
> @@ -437,6 +431,8 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
>
>   	if (likely(!pfnmap)) {
>   		unsigned long tsize_pages = 1 << (tsize + 10 - PAGE_SHIFT);
> +		pgd_t *pgdir;
> +
>   		pfn = gfn_to_pfn_memslot(slot, gfn);
>   		if (is_error_noslot_pfn(pfn)) {
>   			printk(KERN_ERR "Couldn't get real page for gfn %lx!\n",
> @@ -447,9 +443,18 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
>   		/* Align guest and physical address to page map boundaries */
>   		pfn &= ~(tsize_pages - 1);
>   		gvaddr &= ~((tsize_pages << PAGE_SHIFT) - 1);
> +		pgdir = vcpu_e500->vcpu.arch.pgdir;
> +		pte = lookup_linux_pte(pgdir, hva, 1, &tsize_pages);
> +		if (pte_present(pte)) {
> +			wimg = (pte >> PTE_WIMGE_SHIFT) & MAS2_WIMGE_MASK;

This should be
		wimg = (pte_val(pte) >> PTE_WIMGE_SHIFT) & MAS2_WIMGE_MASK;

Tiejun

> +		} else {
> +			printk(KERN_ERR "pte not present: gfn %lx, pfn %lx\n",
> +					(long)gfn, pfn);
> +			return -EINVAL;
> +		}
>   	}
>
> -	kvmppc_e500_ref_setup(ref, gtlbe, pfn);
> +	kvmppc_e500_ref_setup(ref, gtlbe, pfn, wimg);
>
>   	kvmppc_e500_setup_stlbe(&vcpu_e500->vcpu, gtlbe, tsize,
>   				ref, gvaddr, stlbe);
>

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Scott Wood - Aug. 2, 2013, 11:34 p.m.
On Thu, Aug 01, 2013 at 04:42:38PM +0530, Bharat Bhushan wrote:
> diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
> index 17722d8..ebcccc2 100644
> --- a/arch/powerpc/kvm/booke.c
> +++ b/arch/powerpc/kvm/booke.c
> @@ -697,7 +697,7 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
>  #endif
>  
>  	kvmppc_fix_ee_before_entry();
> -
> +	vcpu->arch.pgdir = current->mm->pgd;
>  	ret = __kvmppc_vcpu_run(kvm_run, vcpu);

kvmppc_fix_ee_before_entry() is supposed to be the last thing that
happens before __kvmppc_vcpu_run().

> @@ -332,6 +324,8 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
>  	unsigned long hva;
>  	int pfnmap = 0;
>  	int tsize = BOOK3E_PAGESZ_4K;
> +	pte_t pte;
> +	int wimg = 0;
>  
>  	/*
>  	 * Translate guest physical to true physical, acquiring
> @@ -437,6 +431,8 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
>  
>  	if (likely(!pfnmap)) {
>  		unsigned long tsize_pages = 1 << (tsize + 10 - PAGE_SHIFT);
> +		pgd_t *pgdir;
> +
>  		pfn = gfn_to_pfn_memslot(slot, gfn);
>  		if (is_error_noslot_pfn(pfn)) {
>  			printk(KERN_ERR "Couldn't get real page for gfn %lx!\n",
> @@ -447,9 +443,18 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
>  		/* Align guest and physical address to page map boundaries */
>  		pfn &= ~(tsize_pages - 1);
>  		gvaddr &= ~((tsize_pages << PAGE_SHIFT) - 1);
> +		pgdir = vcpu_e500->vcpu.arch.pgdir;
> +		pte = lookup_linux_pte(pgdir, hva, 1, &tsize_pages);
> +		if (pte_present(pte)) {
> +			wimg = (pte >> PTE_WIMGE_SHIFT) & MAS2_WIMGE_MASK;
> +		} else {
> +			printk(KERN_ERR "pte not present: gfn %lx, pfn %lx\n",
> +					(long)gfn, pfn);
> +			return -EINVAL;
> +		}
>  	}

How does wimg get set in the pfnmap case?

Could you explain why we need to set dirty/referenced on the PTE, when we
didn't need to do that before?  All we're getting from the PTE is wimg. 
We have MMU notifiers to take care of the page being unmapped, and we've
already marked the page itself as dirty if the TLB entry is writeable.

-Scott

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Bharat Bhushan - Aug. 3, 2013, 3:11 a.m.
> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Saturday, August 03, 2013 5:05 AM
> To: Bhushan Bharat-R65777
> Cc: benh@kernel.crashing.org; agraf@suse.de; kvm-ppc@vger.kernel.org;
> kvm@vger.kernel.org; linuxppc-dev@lists.ozlabs.org; Bhushan Bharat-R65777
> Subject: Re: [PATCH 6/6 v2] kvm: powerpc: use caching attributes as per linux
> pte
> 
> On Thu, Aug 01, 2013 at 04:42:38PM +0530, Bharat Bhushan wrote:
> > diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c index
> > 17722d8..ebcccc2 100644
> > --- a/arch/powerpc/kvm/booke.c
> > +++ b/arch/powerpc/kvm/booke.c
> > @@ -697,7 +697,7 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run,
> > struct kvm_vcpu *vcpu)  #endif
> >
> >  	kvmppc_fix_ee_before_entry();
> > -
> > +	vcpu->arch.pgdir = current->mm->pgd;
> >  	ret = __kvmppc_vcpu_run(kvm_run, vcpu);
> 
> kvmppc_fix_ee_before_entry() is supposed to be the last thing that happens
> before __kvmppc_vcpu_run().
> 
> > @@ -332,6 +324,8 @@ static inline int kvmppc_e500_shadow_map(struct
> kvmppc_vcpu_e500 *vcpu_e500,
> >  	unsigned long hva;
> >  	int pfnmap = 0;
> >  	int tsize = BOOK3E_PAGESZ_4K;
> > +	pte_t pte;
> > +	int wimg = 0;
> >
> >  	/*
> >  	 * Translate guest physical to true physical, acquiring @@ -437,6
> > +431,8 @@ static inline int kvmppc_e500_shadow_map(struct
> > kvmppc_vcpu_e500 *vcpu_e500,
> >
> >  	if (likely(!pfnmap)) {
> >  		unsigned long tsize_pages = 1 << (tsize + 10 - PAGE_SHIFT);
> > +		pgd_t *pgdir;
> > +
> >  		pfn = gfn_to_pfn_memslot(slot, gfn);
> >  		if (is_error_noslot_pfn(pfn)) {
> >  			printk(KERN_ERR "Couldn't get real page for gfn %lx!\n", @@
> -447,9
> > +443,18 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500
> *vcpu_e500,
> >  		/* Align guest and physical address to page map boundaries */
> >  		pfn &= ~(tsize_pages - 1);
> >  		gvaddr &= ~((tsize_pages << PAGE_SHIFT) - 1);
> > +		pgdir = vcpu_e500->vcpu.arch.pgdir;
> > +		pte = lookup_linux_pte(pgdir, hva, 1, &tsize_pages);
> > +		if (pte_present(pte)) {
> > +			wimg = (pte >> PTE_WIMGE_SHIFT) & MAS2_WIMGE_MASK;
> > +		} else {
> > +			printk(KERN_ERR "pte not present: gfn %lx, pfn %lx\n",
> > +					(long)gfn, pfn);
> > +			return -EINVAL;
> > +		}
> >  	}
> 
> How does wimg get set in the pfnmap case?

Pfnmap is not kernel managed pages, right? So should we set I+G there ?

> 
> Could you explain why we need to set dirty/referenced on the PTE, when we didn't
> need to do that before? All we're getting from the PTE is wimg.
> We have MMU notifiers to take care of the page being unmapped, and we've already
> marked the page itself as dirty if the TLB entry is writeable.

I pulled this code from book3s.

Ben, can you describe why we need this on book3s ?

Thanks
-Bharat
> 
> -Scott

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Benjamin Herrenschmidt - Aug. 3, 2013, 4:25 a.m.
On Sat, 2013-08-03 at 03:11 +0000, Bhushan Bharat-R65777 wrote:
> 
> > 
> > Could you explain why we need to set dirty/referenced on the PTE, when we didn't
> > need to do that before? All we're getting from the PTE is wimg.
> > We have MMU notifiers to take care of the page being unmapped, and we've already
> > marked the page itself as dirty if the TLB entry is writeable.
> 
> I pulled this code from book3s.
> 
> Ben, can you describe why we need this on book3s ?

If you let the guest write to the page you must set the dirty bit on the PTE
(or the struct page, at least one of them), similar with accessed on any access.

If you don't, the VM might swap the page out without writing it back to disk
for example, assuming it contains no modified data.

Cheers,
Ben.


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Scott Wood - Aug. 5, 2013, 4:28 p.m.
On Sat, 2013-08-03 at 14:25 +1000, Benjamin Herrenschmidt wrote:
> On Sat, 2013-08-03 at 03:11 +0000, Bhushan Bharat-R65777 wrote:
> > 
> > > 
> > > Could you explain why we need to set dirty/referenced on the PTE, when we didn't
> > > need to do that before? All we're getting from the PTE is wimg.
> > > We have MMU notifiers to take care of the page being unmapped, and we've already
> > > marked the page itself as dirty if the TLB entry is writeable.
> > 
> > I pulled this code from book3s.
> > 
> > Ben, can you describe why we need this on book3s ?
> 
> If you let the guest write to the page you must set the dirty bit on the PTE
> (or the struct page, at least one of them), similar with accessed on any access.
> 
> If you don't, the VM might swap the page out without writing it back to disk
> for example, assuming it contains no modified data.

We've already marked the page itself as dirty using kvm_set_pfn_dirty(),
and if the VM swaps it out we'll get an MMU notifier callback.  If we
marked the PTE dirty/accessed instead, is there any guarantee it will
stay marked dirty/accessed until the next MMU notifier?

-Scott



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Scott Wood - Aug. 5, 2013, 4:30 p.m.
On Fri, 2013-08-02 at 22:11 -0500, Bhushan Bharat-R65777 wrote:
> > How does wimg get set in the pfnmap case?
> 
> Pfnmap is not kernel managed pages, right? So should we set I+G there ?

It could depend on ppc_md.phys_mem_access_prot().  Can't you pull it
from the PTE regardless of pfnmap?

-Scott



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Patch

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 3328353..583d405 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -535,6 +535,7 @@  struct kvm_vcpu_arch {
 #endif
 	gpa_t paddr_accessed;
 	gva_t vaddr_accessed;
+	pgd_t *pgdir;
 
 	u8 io_gpr; /* GPR used as IO source/target */
 	u8 mmio_is_bigendian;
@@ -592,7 +593,6 @@  struct kvm_vcpu_arch {
 	struct list_head run_list;
 	struct task_struct *run_task;
 	struct kvm_run *kvm_run;
-	pgd_t *pgdir;
 
 	spinlock_t vpa_update_lock;
 	struct kvmppc_vpa vpa;
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 17722d8..ebcccc2 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -697,7 +697,7 @@  int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
 #endif
 
 	kvmppc_fix_ee_before_entry();
-
+	vcpu->arch.pgdir = current->mm->pgd;
 	ret = __kvmppc_vcpu_run(kvm_run, vcpu);
 
 	/* No need for kvm_guest_exit. It's done in handle_exit.
diff --git a/arch/powerpc/kvm/e500.h b/arch/powerpc/kvm/e500.h
index 4fd9650..fc4b2f6 100644
--- a/arch/powerpc/kvm/e500.h
+++ b/arch/powerpc/kvm/e500.h
@@ -31,11 +31,13 @@  enum vcpu_ftr {
 #define E500_TLB_NUM   2
 
 /* entry is mapped somewhere in host TLB */
-#define E500_TLB_VALID		(1 << 0)
+#define E500_TLB_VALID		(1 << 31)
 /* TLB1 entry is mapped by host TLB1, tracked by bitmaps */
-#define E500_TLB_BITMAP		(1 << 1)
+#define E500_TLB_BITMAP		(1 << 30)
 /* TLB1 entry is mapped by host TLB0 */
-#define E500_TLB_TLB0		(1 << 2)
+#define E500_TLB_TLB0		(1 << 29)
+/* Lower 5 bits have WIMGE value */
+#define E500_TLB_WIMGE_MASK	(0x1f)
 
 struct tlbe_ref {
 	pfn_t pfn;		/* valid only for TLB0, except briefly */
diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c
index 1c6a9d7..9b10b0b 100644
--- a/arch/powerpc/kvm/e500_mmu_host.c
+++ b/arch/powerpc/kvm/e500_mmu_host.c
@@ -64,15 +64,6 @@  static inline u32 e500_shadow_mas3_attrib(u32 mas3, int usermode)
 	return mas3;
 }
 
-static inline u32 e500_shadow_mas2_attrib(u32 mas2, int usermode)
-{
-#ifdef CONFIG_SMP
-	return (mas2 & MAS2_ATTRIB_MASK) | MAS2_M;
-#else
-	return mas2 & MAS2_ATTRIB_MASK;
-#endif
-}
-
 /*
  * writing shadow tlb entry to host TLB
  */
@@ -248,10 +239,12 @@  static inline int tlbe_is_writable(struct kvm_book3e_206_tlb_entry *tlbe)
 
 static inline void kvmppc_e500_ref_setup(struct tlbe_ref *ref,
 					 struct kvm_book3e_206_tlb_entry *gtlbe,
-					 pfn_t pfn)
+					 pfn_t pfn, int wimg)
 {
 	ref->pfn = pfn;
 	ref->flags |= E500_TLB_VALID;
+	/* Use guest supplied MAS2_G and MAS2_E */
+	ref->flags |= (gtlbe->mas2 & MAS2_ATTRIB_MASK) | wimg;
 
 	if (tlbe_is_writable(gtlbe))
 		kvm_set_pfn_dirty(pfn);
@@ -312,8 +305,7 @@  static void kvmppc_e500_setup_stlbe(
 
 	/* Force IPROT=0 for all guest mappings. */
 	stlbe->mas1 = MAS1_TSIZE(tsize) | get_tlb_sts(gtlbe) | MAS1_VALID;
-	stlbe->mas2 = (gvaddr & MAS2_EPN) |
-		      e500_shadow_mas2_attrib(gtlbe->mas2, pr);
+	stlbe->mas2 = (gvaddr & MAS2_EPN) | (ref->flags & E500_TLB_WIMGE_MASK);
 	stlbe->mas7_3 = ((u64)pfn << PAGE_SHIFT) |
 			e500_shadow_mas3_attrib(gtlbe->mas7_3, pr);
 
@@ -332,6 +324,8 @@  static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
 	unsigned long hva;
 	int pfnmap = 0;
 	int tsize = BOOK3E_PAGESZ_4K;
+	pte_t pte;
+	int wimg = 0;
 
 	/*
 	 * Translate guest physical to true physical, acquiring
@@ -437,6 +431,8 @@  static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
 
 	if (likely(!pfnmap)) {
 		unsigned long tsize_pages = 1 << (tsize + 10 - PAGE_SHIFT);
+		pgd_t *pgdir;
+
 		pfn = gfn_to_pfn_memslot(slot, gfn);
 		if (is_error_noslot_pfn(pfn)) {
 			printk(KERN_ERR "Couldn't get real page for gfn %lx!\n",
@@ -447,9 +443,18 @@  static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
 		/* Align guest and physical address to page map boundaries */
 		pfn &= ~(tsize_pages - 1);
 		gvaddr &= ~((tsize_pages << PAGE_SHIFT) - 1);
+		pgdir = vcpu_e500->vcpu.arch.pgdir;
+		pte = lookup_linux_pte(pgdir, hva, 1, &tsize_pages);
+		if (pte_present(pte)) {
+			wimg = (pte >> PTE_WIMGE_SHIFT) & MAS2_WIMGE_MASK;
+		} else {
+			printk(KERN_ERR "pte not present: gfn %lx, pfn %lx\n",
+					(long)gfn, pfn);
+			return -EINVAL;
+		}
 	}
 
-	kvmppc_e500_ref_setup(ref, gtlbe, pfn);
+	kvmppc_e500_ref_setup(ref, gtlbe, pfn, wimg);
 
 	kvmppc_e500_setup_stlbe(&vcpu_e500->vcpu, gtlbe, tsize,
 				ref, gvaddr, stlbe);