[PATCH RFC v8 02/56] KVM: x86: Add 'update_mem_attr' x86 op

[Michael Roth]

This callback will do any platform-specific handling needed for
converting pages between shared/private.

Signed-off-by: Michael Roth <michael.roth@xxxxxxx>
---
 arch/x86/include/asm/kvm-x86-ops.h |  1 +
 arch/x86/include/asm/kvm_host.h    |  2 ++
 arch/x86/kvm/mmu/mmu.c             | 13 +++++++++++++
 include/linux/kvm_host.h           |  4 ++++
 virt/kvm/kvm_main.c                | 29 +++++++++++++++++++++++++++++
 5 files changed, 49 insertions(+)

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 72183da010b8..a8aaf532c2ab 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -132,6 +132,7 @@ KVM_X86_OP(complete_emulated_msr)
 KVM_X86_OP(vcpu_deliver_sipi_vector)
 KVM_X86_OP_OPTIONAL_RET0(vcpu_get_apicv_inhibit_reasons);
 KVM_X86_OP_OPTIONAL_RET0(fault_is_private);
+KVM_X86_OP_OPTIONAL_RET0(update_mem_attr)
 
 #undef KVM_X86_OP
 #undef KVM_X86_OP_OPTIONAL
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f856d689dda0..2da3fb2d5d1b 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1644,6 +1644,8 @@ struct kvm_x86_ops {
 	void (*load_mmu_pgd)(struct kvm_vcpu *vcpu, hpa_t root_hpa,
 			     int root_level);
 	bool (*fault_is_private)(struct kvm *kvm, gpa_t gpa, u64 error_code, bool *private_fault);
+	int (*update_mem_attr)(struct kvm_memory_slot *slot, unsigned int attr,
+			       gfn_t start, gfn_t end);
 
 	bool (*has_wbinvd_exit)(void);
 
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index fb3f34b7391c..053bd77bbf52 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -7251,4 +7251,17 @@ void kvm_arch_set_memory_attributes(struct kvm *kvm,
 		linfo_update_mixed(gfn, slot, level, mixed);
 	}
 }
+
+void kvm_arch_post_set_memory_attributes(struct kvm *kvm,
+					 struct kvm_memory_slot *slot,
+					 unsigned long attrs,
+					 gfn_t start, gfn_t end)
+{
+	int ret;
+
+	ret = static_call(kvm_x86_update_mem_attr)(slot, attrs, start, end);
+	if (ret)
+		pr_warn_ratelimited("Failed to update GFN range 0x%llx-0x%llx with attributes 0x%lx. Ret: %d\n",
+				    start, end, attrs, ret);
+}
 #endif
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index fdc59479b3e2..d200b8f45583 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2330,6 +2330,10 @@ void kvm_arch_set_memory_attributes(struct kvm *kvm,
 				    struct kvm_memory_slot *slot,
 				    unsigned long attrs,
 				    gfn_t start, gfn_t end);
+void kvm_arch_post_set_memory_attributes(struct kvm *kvm,
+					 struct kvm_memory_slot *slot,
+					 unsigned long attrs,
+					 gfn_t start, gfn_t end);
 
 static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
 {
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index b68574ff6c30..8ec985f1c57d 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2561,6 +2561,32 @@ static void kvm_mem_attrs_changed(struct kvm *kvm, unsigned long attrs,
 		kvm_flush_remote_tlbs(kvm);
 }
 
+static void kvm_post_mem_attrs_changed(struct kvm *kvm, unsigned long attrs,
+				       gfn_t start_orig, gfn_t end_orig)
+{
+	struct kvm_memory_slot *slot;
+	struct kvm_memslots *slots;
+	struct kvm_memslot_iter iter;
+	int i;
+
+	for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
+		slots = __kvm_memslots(kvm, i);
+
+		kvm_for_each_memslot_in_gfn_range(&iter, slots, start_orig, end_orig) {
+			gfn_t start, end;
+
+			slot = iter.slot;
+			start = max(start_orig, slot->base_gfn);
+			end = min(end_orig, slot->base_gfn + slot->npages);
+
+			if (start >= end)
+				continue;
+
+			kvm_arch_post_set_memory_attributes(kvm, slot, attrs, start, end);
+		}
+	}
+}
+
 static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
 					   struct kvm_memory_attributes *attrs)
 {
@@ -2602,6 +2628,9 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
 	kvm_mmu_invalidate_end(kvm);
 	KVM_MMU_UNLOCK(kvm);
 
+	if (i > start)
+		kvm_post_mem_attrs_changed(kvm, attrs->attributes, start, i);
+
 	mutex_unlock(&kvm->slots_lock);
 
 	attrs->address = i << PAGE_SHIFT;
-- 
2.25.1