Subject: [RFC PATCH v4 5/6] kvmppc: Radix changes for secure guest

From: Bharata B Rao <[email-masked]>
Date: Tue, 28 May 2019 12:19:32 +0530

- 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.

Signed-off-by: Bharata B Rao <[email-masked]>
---
 arch/powerpc/include/asm/kvm_host.h       | 13 +++++++++++++
 arch/powerpc/include/asm/ultravisor-api.h |  1 +
 arch/powerpc/include/asm/ultravisor.h     |  7 +++++++
 arch/powerpc/kvm/book3s_64_mmu_radix.c    | 19 +++++++++++++++++++
 arch/powerpc/kvm/book3s_hv_hmm.c          | 23 +++++++++++++++++++++++
 5 files changed, 63 insertions(+)

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 845fd2a73506..63d56f7a357e 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -866,6 +866,8 @@ static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {}
 extern int kvmppc_hmm_init(void);
 extern void kvmppc_hmm_free(void);
 extern void kvmppc_hmm_release_pfns(struct kvm_memory_slot *free);
+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)
 {
@@ -874,6 +876,17 @@ static inline int kvmppc_hmm_init(void)
 
 static inline void kvmppc_hmm_free(void) {}
 static inline void kvmppc_hmm_release_pfns(struct kvm_memory_slot *free) {}
+
+
+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 35b71e01177d..eaca65ea2070 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 5113457c4743..28dbc0f0eddb 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..e5d63449ad77 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;
diff --git a/arch/powerpc/kvm/book3s_hv_hmm.c b/arch/powerpc/kvm/book3s_hv_hmm.c
index 18fec814401d..a0d47fc140b6 100644
--- a/arch/powerpc/kvm/book3s_hv_hmm.c
+++ b/arch/powerpc/kvm/book3s_hv_hmm.c
@@ -55,6 +55,11 @@ 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;
@@ -478,6 +483,24 @@ 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)
+{
+	int srcu_idx;
+	unsigned long pfn;
+	int ret;
+
+	srcu_idx = srcu_read_lock(&kvm->srcu);
+	pfn = gfn_to_pfn(kvm, gpa >> PAGE_SHIFT);
+	srcu_read_unlock(&kvm->srcu, srcu_idx);
+	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;
-- 
2.17.1