diff mbox series

[v7,5/7] kvmppc: Radix changes for secure guest

Message ID 20190822102620.21897-6-bharata@linux.ibm.com (mailing list archive)
State New, archived
Headers show
Series KVMPPC driver to manage secure guest pages | expand

Commit Message

Bharata B Rao Aug. 22, 2019, 10:26 a.m. UTC 
- After the guest becomes secure, when we handle a page fault of a page
  belonging to SVM in HV, send that page to UV via UV_PAGE_IN.
- Whenever a page is unmapped on the HV side, inform UV via UV_PAGE_INVAL.
- Ensure all those routines that walk the secondary page tables of
  the guest don't do so in case of secure VM. For secure guest, the
  active secondary page tables are in secure memory and the secondary
  page tables in HV are freed when guest becomes secure.

Signed-off-by: Bharata B Rao <bharata@linux.ibm.com>
---
 arch/powerpc/include/asm/kvm_host.h       | 12 ++++++++++++
 arch/powerpc/include/asm/ultravisor-api.h |  1 +
 arch/powerpc/include/asm/ultravisor.h     |  5 +++++
 arch/powerpc/kvm/book3s_64_mmu_radix.c    | 22 ++++++++++++++++++++++
 arch/powerpc/kvm/book3s_hv_devm.c         | 20 ++++++++++++++++++++
 5 files changed, 60 insertions(+)

Comments

Sukadev Bhattiprolu Aug. 29, 2019, 3:05 a.m. UTC | #1 
> - After the guest becomes secure, when we handle a page fault of a page
>   belonging to SVM in HV, send that page to UV via UV_PAGE_IN.
> - Whenever a page is unmapped on the HV side, inform UV via UV_PAGE_INVAL.
> - Ensure all those routines that walk the secondary page tables of
>   the guest don't do so in case of secure VM. For secure guest, the
>   active secondary page tables are in secure memory and the secondary
>   page tables in HV are freed when guest becomes secure.
> 
> Signed-off-by: Bharata B Rao <bharata@linux.ibm.com>
> ---
>  arch/powerpc/include/asm/kvm_host.h       | 12 ++++++++++++
>  arch/powerpc/include/asm/ultravisor-api.h |  1 +
>  arch/powerpc/include/asm/ultravisor.h     |  5 +++++
>  arch/powerpc/kvm/book3s_64_mmu_radix.c    | 22 ++++++++++++++++++++++
>  arch/powerpc/kvm/book3s_hv_devm.c         | 20 ++++++++++++++++++++
>  5 files changed, 60 insertions(+)
> 
> diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
> index 66e5cc8c9759..29333e8de1c4 100644
> --- a/arch/powerpc/include/asm/kvm_host.h
> +++ b/arch/powerpc/include/asm/kvm_host.h
> @@ -867,6 +867,8 @@ static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {}
>  #ifdef CONFIG_PPC_UV
>  extern int kvmppc_devm_init(void);
>  extern void kvmppc_devm_free(void);
> +extern bool kvmppc_is_guest_secure(struct kvm *kvm);
> +extern int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gpa);
>  #else
>  static inline int kvmppc_devm_init(void)
>  {
> @@ -874,6 +876,16 @@ static inline int kvmppc_devm_init(void)
>  }
> 
>  static inline void kvmppc_devm_free(void) {}
> +
> +static inline bool kvmppc_is_guest_secure(struct kvm *kvm)
> +{
> +	return false;
> +}
> +
> +static inline int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gpa)
> +{
> +	return -EFAULT;
> +}
>  #endif /* CONFIG_PPC_UV */
> 
>  #endif /* __POWERPC_KVM_HOST_H__ */
> diff --git a/arch/powerpc/include/asm/ultravisor-api.h b/arch/powerpc/include/asm/ultravisor-api.h
> index 46b1ee381695..cf200d4ce703 100644
> --- a/arch/powerpc/include/asm/ultravisor-api.h
> +++ b/arch/powerpc/include/asm/ultravisor-api.h
> @@ -29,5 +29,6 @@
>  #define UV_UNREGISTER_MEM_SLOT		0xF124
>  #define UV_PAGE_IN			0xF128
>  #define UV_PAGE_OUT			0xF12C
> +#define UV_PAGE_INVAL			0xF138
> 
>  #endif /* _ASM_POWERPC_ULTRAVISOR_API_H */
> diff --git a/arch/powerpc/include/asm/ultravisor.h b/arch/powerpc/include/asm/ultravisor.h
> index 719c0c3930b9..b333241bbe4c 100644
> --- a/arch/powerpc/include/asm/ultravisor.h
> +++ b/arch/powerpc/include/asm/ultravisor.h
> @@ -57,4 +57,9 @@ static inline int uv_unregister_mem_slot(u64 lpid, u64 slotid)
>  	return ucall_norets(UV_UNREGISTER_MEM_SLOT, lpid, slotid);
>  }
> 
> +static inline int uv_page_inval(u64 lpid, u64 gpa, u64 page_shift)
> +{
> +	return ucall_norets(UV_PAGE_INVAL, lpid, gpa, page_shift);
> +}
> +
>  #endif	/* _ASM_POWERPC_ULTRAVISOR_H */
> diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
> index 2d415c36a61d..93ad34e63045 100644
> --- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
> +++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
> @@ -19,6 +19,8 @@
>  #include <asm/pgtable.h>
>  #include <asm/pgalloc.h>
>  #include <asm/pte-walk.h>
> +#include <asm/ultravisor.h>
> +#include <asm/kvm_host.h>
> 
>  /*
>   * Supported radix tree geometry.
> @@ -915,6 +917,9 @@ int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
>  	if (!(dsisr & DSISR_PRTABLE_FAULT))
>  		gpa |= ea & 0xfff;
> 
> +	if (kvmppc_is_guest_secure(kvm))
> +		return kvmppc_send_page_to_uv(kvm, gpa & PAGE_MASK);
> +
>  	/* Get the corresponding memslot */
>  	memslot = gfn_to_memslot(kvm, gfn);
> 
> @@ -972,6 +977,11 @@ int kvm_unmap_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
>  	unsigned long gpa = gfn << PAGE_SHIFT;
>  	unsigned int shift;
> 
> +	if (kvmppc_is_guest_secure(kvm)) {
> +		uv_page_inval(kvm->arch.lpid, gpa, PAGE_SIZE);
> +		return 0;
> +	}

If it is a page we share with UV, won't we need to drop the HV mapping
for the page?
> +
>  	ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
>  	if (ptep && pte_present(*ptep))
>  		kvmppc_unmap_pte(kvm, ptep, gpa, shift, memslot,
> @@ -989,6 +999,9 @@ int kvm_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
>  	int ref = 0;
>  	unsigned long old, *rmapp;
> 
> +	if (kvmppc_is_guest_secure(kvm))
> +		return ref;
> +
>  	ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
>  	if (ptep && pte_present(*ptep) && pte_young(*ptep)) {
>  		old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_ACCESSED, 0,
> @@ -1013,6 +1026,9 @@ int kvm_test_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
>  	unsigned int shift;
>  	int ref = 0;
> 
> +	if (kvmppc_is_guest_secure(kvm))
> +		return ref;
> +
>  	ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
>  	if (ptep && pte_present(*ptep) && pte_young(*ptep))
>  		ref = 1;
> @@ -1030,6 +1046,9 @@ static int kvm_radix_test_clear_dirty(struct kvm *kvm,
>  	int ret = 0;
>  	unsigned long old, *rmapp;
> 
> +	if (kvmppc_is_guest_secure(kvm))
> +		return ret;
> +
>  	ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
>  	if (ptep && pte_present(*ptep) && pte_dirty(*ptep)) {
>  		ret = 1;
> @@ -1082,6 +1101,9 @@ void kvmppc_radix_flush_memslot(struct kvm *kvm,
>  	unsigned long gpa;
>  	unsigned int shift;
> 
> +	if (kvmppc_is_guest_secure(kvm))
> +		return;
> +
>  	gpa = memslot->base_gfn << PAGE_SHIFT;
>  	spin_lock(&kvm->mmu_lock);
>  	for (n = memslot->npages; n; --n) {
> diff --git a/arch/powerpc/kvm/book3s_hv_devm.c b/arch/powerpc/kvm/book3s_hv_devm.c
> index 494495806407..19cfad340a51 100644
> --- a/arch/powerpc/kvm/book3s_hv_devm.c
> +++ b/arch/powerpc/kvm/book3s_hv_devm.c
> @@ -49,6 +49,11 @@ struct kvmppc_devm_page_pvt {
>  	bool skip_page_out;
>  };
> 
> +bool kvmppc_is_guest_secure(struct kvm *kvm)
> +{
> +	return !!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_DONE);
> +}
> +
>  unsigned long kvmppc_h_svm_init_start(struct kvm *kvm)
>  {
>  	struct kvm_memslots *slots;
> @@ -453,6 +458,21 @@ kvmppc_h_svm_page_out(struct kvm *kvm, unsigned long gpa,
>  	return ret;
>  }
> 
> +int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gpa)
> +{
> +	unsigned long pfn;
> +	int ret;
> +
> +	pfn = gfn_to_pfn(kvm, gpa >> PAGE_SHIFT);
> +	if (is_error_noslot_pfn(pfn))
> +		return -EFAULT;
> +
> +	ret = uv_page_in(kvm->arch.lpid, pfn << PAGE_SHIFT, gpa, 0, PAGE_SHIFT);
> +	kvm_release_pfn_clean(pfn);
> +
> +	return (ret == U_SUCCESS) ? RESUME_GUEST : -EFAULT;
> +}
> +
>  static u64 kvmppc_get_secmem_size(void)
>  {
>  	struct device_node *np;
> -- 
> 2.21.0
Bharata B Rao Aug. 29, 2019, 7:57 a.m. UTC | #2 
On Wed, Aug 28, 2019 at 08:05:52PM -0700, Sukadev Bhattiprolu wrote:
> > - After the guest becomes secure, when we handle a page fault of a page
> >   belonging to SVM in HV, send that page to UV via UV_PAGE_IN.
> > - Whenever a page is unmapped on the HV side, inform UV via UV_PAGE_INVAL.
> > - Ensure all those routines that walk the secondary page tables of
> >   the guest don't do so in case of secure VM. For secure guest, the
> >   active secondary page tables are in secure memory and the secondary
> >   page tables in HV are freed when guest becomes secure.
> > 
> > Signed-off-by: Bharata B Rao <bharata@linux.ibm.com>
> > ---
> >  arch/powerpc/include/asm/kvm_host.h       | 12 ++++++++++++
> >  arch/powerpc/include/asm/ultravisor-api.h |  1 +
> >  arch/powerpc/include/asm/ultravisor.h     |  5 +++++
> >  arch/powerpc/kvm/book3s_64_mmu_radix.c    | 22 ++++++++++++++++++++++
> >  arch/powerpc/kvm/book3s_hv_devm.c         | 20 ++++++++++++++++++++
> >  5 files changed, 60 insertions(+)
> > 
> > diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
> > index 66e5cc8c9759..29333e8de1c4 100644
> > --- a/arch/powerpc/include/asm/kvm_host.h
> > +++ b/arch/powerpc/include/asm/kvm_host.h
> > @@ -867,6 +867,8 @@ static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {}
> >  #ifdef CONFIG_PPC_UV
> >  extern int kvmppc_devm_init(void);
> >  extern void kvmppc_devm_free(void);
> > +extern bool kvmppc_is_guest_secure(struct kvm *kvm);
> > +extern int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gpa);
> >  #else
> >  static inline int kvmppc_devm_init(void)
> >  {
> > @@ -874,6 +876,16 @@ static inline int kvmppc_devm_init(void)
> >  }
> > 
> >  static inline void kvmppc_devm_free(void) {}
> > +
> > +static inline bool kvmppc_is_guest_secure(struct kvm *kvm)
> > +{
> > +	return false;
> > +}
> > +
> > +static inline int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gpa)
> > +{
> > +	return -EFAULT;
> > +}
> >  #endif /* CONFIG_PPC_UV */
> > 
> >  #endif /* __POWERPC_KVM_HOST_H__ */
> > diff --git a/arch/powerpc/include/asm/ultravisor-api.h b/arch/powerpc/include/asm/ultravisor-api.h
> > index 46b1ee381695..cf200d4ce703 100644
> > --- a/arch/powerpc/include/asm/ultravisor-api.h
> > +++ b/arch/powerpc/include/asm/ultravisor-api.h
> > @@ -29,5 +29,6 @@
> >  #define UV_UNREGISTER_MEM_SLOT		0xF124
> >  #define UV_PAGE_IN			0xF128
> >  #define UV_PAGE_OUT			0xF12C
> > +#define UV_PAGE_INVAL			0xF138
> > 
> >  #endif /* _ASM_POWERPC_ULTRAVISOR_API_H */
> > diff --git a/arch/powerpc/include/asm/ultravisor.h b/arch/powerpc/include/asm/ultravisor.h
> > index 719c0c3930b9..b333241bbe4c 100644
> > --- a/arch/powerpc/include/asm/ultravisor.h
> > +++ b/arch/powerpc/include/asm/ultravisor.h
> > @@ -57,4 +57,9 @@ static inline int uv_unregister_mem_slot(u64 lpid, u64 slotid)
> >  	return ucall_norets(UV_UNREGISTER_MEM_SLOT, lpid, slotid);
> >  }
> > 
> > +static inline int uv_page_inval(u64 lpid, u64 gpa, u64 page_shift)
> > +{
> > +	return ucall_norets(UV_PAGE_INVAL, lpid, gpa, page_shift);
> > +}
> > +
> >  #endif	/* _ASM_POWERPC_ULTRAVISOR_H */
> > diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
> > index 2d415c36a61d..93ad34e63045 100644
> > --- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
> > +++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
> > @@ -19,6 +19,8 @@
> >  #include <asm/pgtable.h>
> >  #include <asm/pgalloc.h>
> >  #include <asm/pte-walk.h>
> > +#include <asm/ultravisor.h>
> > +#include <asm/kvm_host.h>
> > 
> >  /*
> >   * Supported radix tree geometry.
> > @@ -915,6 +917,9 @@ int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
> >  	if (!(dsisr & DSISR_PRTABLE_FAULT))
> >  		gpa |= ea & 0xfff;
> > 
> > +	if (kvmppc_is_guest_secure(kvm))
> > +		return kvmppc_send_page_to_uv(kvm, gpa & PAGE_MASK);
> > +
> >  	/* Get the corresponding memslot */
> >  	memslot = gfn_to_memslot(kvm, gfn);
> > 
> > @@ -972,6 +977,11 @@ int kvm_unmap_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
> >  	unsigned long gpa = gfn << PAGE_SHIFT;
> >  	unsigned int shift;
> > 
> > +	if (kvmppc_is_guest_secure(kvm)) {
> > +		uv_page_inval(kvm->arch.lpid, gpa, PAGE_SIZE);
> > +		return 0;
> > +	}
> 
> If it is a page we share with UV, won't we need to drop the HV mapping
> for the page?

I believe we come here via MMU notifies only after dropping HV mapping.

Regards,
Bharata.
diff mbox series

Patch

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 66e5cc8c9759..29333e8de1c4 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -867,6 +867,8 @@  static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {}
 #ifdef CONFIG_PPC_UV
 extern int kvmppc_devm_init(void);
 extern void kvmppc_devm_free(void);
+extern bool kvmppc_is_guest_secure(struct kvm *kvm);
+extern int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gpa);
 #else
 static inline int kvmppc_devm_init(void)
 {
@@ -874,6 +876,16 @@  static inline int kvmppc_devm_init(void)
 }
 
 static inline void kvmppc_devm_free(void) {}
+
+static inline bool kvmppc_is_guest_secure(struct kvm *kvm)
+{
+	return false;
+}
+
+static inline int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gpa)
+{
+	return -EFAULT;
+}
 #endif /* CONFIG_PPC_UV */
 
 #endif /* __POWERPC_KVM_HOST_H__ */
diff --git a/arch/powerpc/include/asm/ultravisor-api.h b/arch/powerpc/include/asm/ultravisor-api.h
index 46b1ee381695..cf200d4ce703 100644
--- a/arch/powerpc/include/asm/ultravisor-api.h
+++ b/arch/powerpc/include/asm/ultravisor-api.h
@@ -29,5 +29,6 @@ 
 #define UV_UNREGISTER_MEM_SLOT		0xF124
 #define UV_PAGE_IN			0xF128
 #define UV_PAGE_OUT			0xF12C
+#define UV_PAGE_INVAL			0xF138
 
 #endif /* _ASM_POWERPC_ULTRAVISOR_API_H */
diff --git a/arch/powerpc/include/asm/ultravisor.h b/arch/powerpc/include/asm/ultravisor.h
index 719c0c3930b9..b333241bbe4c 100644
--- a/arch/powerpc/include/asm/ultravisor.h
+++ b/arch/powerpc/include/asm/ultravisor.h
@@ -57,4 +57,9 @@  static inline int uv_unregister_mem_slot(u64 lpid, u64 slotid)
 	return ucall_norets(UV_UNREGISTER_MEM_SLOT, lpid, slotid);
 }
 
+static inline int uv_page_inval(u64 lpid, u64 gpa, u64 page_shift)
+{
+	return ucall_norets(UV_PAGE_INVAL, lpid, gpa, page_shift);
+}
+
 #endif	/* _ASM_POWERPC_ULTRAVISOR_H */
diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index 2d415c36a61d..93ad34e63045 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -19,6 +19,8 @@ 
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
 #include <asm/pte-walk.h>
+#include <asm/ultravisor.h>
+#include <asm/kvm_host.h>
 
 /*
  * Supported radix tree geometry.
@@ -915,6 +917,9 @@  int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
 	if (!(dsisr & DSISR_PRTABLE_FAULT))
 		gpa |= ea & 0xfff;
 
+	if (kvmppc_is_guest_secure(kvm))
+		return kvmppc_send_page_to_uv(kvm, gpa & PAGE_MASK);
+
 	/* Get the corresponding memslot */
 	memslot = gfn_to_memslot(kvm, gfn);
 
@@ -972,6 +977,11 @@  int kvm_unmap_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
 	unsigned long gpa = gfn << PAGE_SHIFT;
 	unsigned int shift;
 
+	if (kvmppc_is_guest_secure(kvm)) {
+		uv_page_inval(kvm->arch.lpid, gpa, PAGE_SIZE);
+		return 0;
+	}
+
 	ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
 	if (ptep && pte_present(*ptep))
 		kvmppc_unmap_pte(kvm, ptep, gpa, shift, memslot,
@@ -989,6 +999,9 @@  int kvm_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
 	int ref = 0;
 	unsigned long old, *rmapp;
 
+	if (kvmppc_is_guest_secure(kvm))
+		return ref;
+
 	ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
 	if (ptep && pte_present(*ptep) && pte_young(*ptep)) {
 		old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_ACCESSED, 0,
@@ -1013,6 +1026,9 @@  int kvm_test_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
 	unsigned int shift;
 	int ref = 0;
 
+	if (kvmppc_is_guest_secure(kvm))
+		return ref;
+
 	ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
 	if (ptep && pte_present(*ptep) && pte_young(*ptep))
 		ref = 1;
@@ -1030,6 +1046,9 @@  static int kvm_radix_test_clear_dirty(struct kvm *kvm,
 	int ret = 0;
 	unsigned long old, *rmapp;
 
+	if (kvmppc_is_guest_secure(kvm))
+		return ret;
+
 	ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
 	if (ptep && pte_present(*ptep) && pte_dirty(*ptep)) {
 		ret = 1;
@@ -1082,6 +1101,9 @@  void kvmppc_radix_flush_memslot(struct kvm *kvm,
 	unsigned long gpa;
 	unsigned int shift;
 
+	if (kvmppc_is_guest_secure(kvm))
+		return;
+
 	gpa = memslot->base_gfn << PAGE_SHIFT;
 	spin_lock(&kvm->mmu_lock);
 	for (n = memslot->npages; n; --n) {
diff --git a/arch/powerpc/kvm/book3s_hv_devm.c b/arch/powerpc/kvm/book3s_hv_devm.c
index 494495806407..19cfad340a51 100644
--- a/arch/powerpc/kvm/book3s_hv_devm.c
+++ b/arch/powerpc/kvm/book3s_hv_devm.c
@@ -49,6 +49,11 @@  struct kvmppc_devm_page_pvt {
 	bool skip_page_out;
 };
 
+bool kvmppc_is_guest_secure(struct kvm *kvm)
+{
+	return !!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_DONE);
+}
+
 unsigned long kvmppc_h_svm_init_start(struct kvm *kvm)
 {
 	struct kvm_memslots *slots;
@@ -453,6 +458,21 @@  kvmppc_h_svm_page_out(struct kvm *kvm, unsigned long gpa,
 	return ret;
 }
 
+int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gpa)
+{
+	unsigned long pfn;
+	int ret;
+
+	pfn = gfn_to_pfn(kvm, gpa >> PAGE_SHIFT);
+	if (is_error_noslot_pfn(pfn))
+		return -EFAULT;
+
+	ret = uv_page_in(kvm->arch.lpid, pfn << PAGE_SHIFT, gpa, 0, PAGE_SHIFT);
+	kvm_release_pfn_clean(pfn);
+
+	return (ret == U_SUCCESS) ? RESUME_GUEST : -EFAULT;
+}
+
 static u64 kvmppc_get_secmem_size(void)
 {
 	struct device_node *np;