[RFC,v5,5/7] kvmppc: Radix changes for secure guest

- 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     |  7 +++++++
 arch/powerpc/kvm/book3s_64_mmu_radix.c    | 22 ++++++++++++++++++++++
 arch/powerpc/kvm/book3s_hv_hmm.c          | 20 ++++++++++++++++++++
 5 files changed, 62 insertions(+)

On 2019-07-09 05:25, Bharata B Rao 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>
  Reviewed-by: Janani Janakiraman <janani@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     |  7 +++++++
>  arch/powerpc/kvm/book3s_64_mmu_radix.c    | 22 ++++++++++++++++++++++
>  arch/powerpc/kvm/book3s_hv_hmm.c          | 20 ++++++++++++++++++++
>  5 files changed, 62 insertions(+)
> 
> diff --git a/arch/powerpc/include/asm/kvm_host.h
> b/arch/powerpc/include/asm/kvm_host.h
> index 0c49c3401c63..dcbf7480cb10 100644
> --- a/arch/powerpc/include/asm/kvm_host.h
> +++ b/arch/powerpc/include/asm/kvm_host.h
> @@ -865,6 +865,8 @@ static inline void
> kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {}
>  #ifdef CONFIG_PPC_UV
>  extern int kvmppc_hmm_init(void);
>  extern void kvmppc_hmm_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_hmm_init(void)
>  {
> @@ -872,6 +874,16 @@ static inline int kvmppc_hmm_init(void)
>  }
> 
>  static inline void kvmppc_hmm_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 d6d6eb2e6e6b..9f5510b55892 100644
> --- a/arch/powerpc/include/asm/ultravisor-api.h
> +++ b/arch/powerpc/include/asm/ultravisor-api.h
> @@ -24,5 +24,6 @@
>  #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 fe45be9ee63b..f4f674794b35 100644
> --- a/arch/powerpc/include/asm/ultravisor.h
> +++ b/arch/powerpc/include/asm/ultravisor.h
> @@ -77,6 +77,13 @@ static inline int uv_unregister_mem_slot(u64 lpid,
> u64 slotid)
> 
>  	return ucall(UV_UNREGISTER_MEM_SLOT, retbuf, lpid, slotid);
>  }
> +
> +static inline int uv_page_inval(u64 lpid, u64 gpa, u64 page_shift)
> +{
> +	unsigned long retbuf[UCALL_BUFSIZE];
> +
> +	return ucall(UV_PAGE_INVAL, retbuf, lpid, gpa, page_shift);
> +}
>  #endif /* !__ASSEMBLY__ */
> 
>  #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 f55ef071883f..c454600c454f 100644
> --- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
> +++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
> @@ -21,6 +21,8 @@
>  #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.
> @@ -923,6 +925,9 @@ 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);
> 
> @@ -980,6 +985,11 @@ 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,
> @@ -997,6 +1007,9 @@ 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,
> @@ -1021,6 +1034,9 @@ 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;
> @@ -1038,6 +1054,9 @@ 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;
> @@ -1090,6 +1109,9 @@ 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_hmm.c 
> b/arch/powerpc/kvm/book3s_hv_hmm.c
> index 55bab9c4e60a..9e6c88de456f 100644
> --- a/arch/powerpc/kvm/book3s_hv_hmm.c
> +++ b/arch/powerpc/kvm/book3s_hv_hmm.c
> @@ -62,6 +62,11 @@ struct kvmppc_hmm_migrate_args {
>  	unsigned long page_shift;
>  };
> 
> +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;
> @@ -494,6 +499,21 @@ 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;