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

[janani <janani@xxxxxxxxxxxxx>]

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@xxxxxxxxxxxxx>
 Reviewed-by: Janani Janakiraman <janani@xxxxxxxxxxxxx>
> ---
>  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;