[RFC V2 PATCH 3/8] arch: x86: sev: Populate private memory fd during LAUNCH_UPDATE_DATA

[Vishal Annapurve <vannapurve@google.com>]

This change adds handling of HVA ranges to copy contents
to private memory while doing sev launch update data.

mem_attr array is updated during LAUNCH_UPDATE_DATA to ensure
that encrypted memory is marked as private.

Signed-off-by: Vishal Annapurve <vannapurve@google.com>
---
 arch/x86/kvm/svm/sev.c   | 99 ++++++++++++++++++++++++++++++++++++----
 include/linux/kvm_host.h |  2 +
 virt/kvm/kvm_main.c      | 39 ++++++++++------
 3 files changed, 116 insertions(+), 24 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 309bcdb2f929..673dca318cd4 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -492,23 +492,22 @@ static unsigned long get_num_contig_pages(unsigned long idx,
 	return pages;
 }
 
-static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
+int sev_launch_update_shared_gfn_handler(struct kvm *kvm,
+	struct kvm_gfn_range *range, struct kvm_sev_cmd *argp)
 {
 	unsigned long vaddr, vaddr_end, next_vaddr, npages, pages, size, i;
 	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-	struct kvm_sev_launch_update_data params;
 	struct sev_data_launch_update_data data;
 	struct page **inpages;
 	int ret;
 
-	if (!sev_guest(kvm))
-		return -ENOTTY;
-
-	if (copy_from_user(&params, (void __user *)(uintptr_t)argp->data, sizeof(params)))
-		return -EFAULT;
+	vaddr = gfn_to_hva_memslot(range->slot, range->start);
+	if (kvm_is_error_hva(vaddr)) {
+		pr_err("vaddr is erroneous 0x%lx\n", vaddr);
+		return -EINVAL;
+	}
 
-	vaddr = params.uaddr;
-	size = params.len;
+	size = (range->end - range->start) << PAGE_SHIFT;
 	vaddr_end = vaddr + size;
 
 	/* Lock the user memory. */
@@ -560,6 +559,88 @@ static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	return ret;
 }
 
+int sev_launch_update_priv_gfn_handler(struct kvm *kvm,
+	struct kvm_gfn_range *range, struct kvm_sev_cmd *argp)
+{
+	struct sev_data_launch_update_data data;
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+	gfn_t gfn;
+	kvm_pfn_t pfn;
+	struct kvm_memory_slot *memslot = range->slot;
+	int ret = 0;
+
+	data.reserved = 0;
+	data.handle = sev->handle;
+
+	for (gfn = range->start; gfn < range->end; gfn++) {
+		int order;
+		void *kvaddr;
+
+		ret = kvm_private_mem_get_pfn(memslot,
+			gfn, &pfn, &order);
+		if (ret)
+			return ret;
+
+		kvaddr = pfn_to_kaddr(pfn);
+		if (!virt_addr_valid(kvaddr)) {
+			pr_err("Invalid kvaddr 0x%lx\n", (uint64_t)kvaddr);
+			ret = -EINVAL;
+			goto e_ret;
+		}
+
+		ret = kvm_read_guest_page(kvm, gfn, kvaddr, 0, PAGE_SIZE);
+		if (ret) {
+			pr_err("guest read failed 0x%lx\n", ret);
+			goto e_ret;
+		}
+
+		if (!this_cpu_has(X86_FEATURE_SME_COHERENT))
+			clflush_cache_range(kvaddr, PAGE_SIZE);
+
+		data.len = PAGE_SIZE;
+		data.address = __sme_set(pfn << PAGE_SHIFT);
+		ret = sev_issue_cmd(kvm, SEV_CMD_LAUNCH_UPDATE_DATA, &data, &argp->error);
+		if (ret)
+			goto e_ret;
+
+		kvm_private_mem_put_pfn(memslot, pfn);
+	}
+	kvm_vm_set_region_attr(kvm, range->start, range->end,
+		true /* priv_attr */);
+
+	return ret;
+
+e_ret:
+	kvm_private_mem_put_pfn(memslot, pfn);
+	return ret;
+}
+
+int sev_launch_update_gfn_handler(struct kvm *kvm,
+	struct kvm_gfn_range *range, void *data)
+{
+	struct kvm_sev_cmd *argp = (struct kvm_sev_cmd *)data;
+
+	if (kvm_slot_can_be_private(range->slot))
+		return sev_launch_update_priv_gfn_handler(kvm, range, argp);
+
+	return sev_launch_update_shared_gfn_handler(kvm, range, argp);
+}
+
+static int sev_launch_update_data(struct kvm *kvm,
+		struct kvm_sev_cmd *argp)
+{
+	struct kvm_sev_launch_update_data params;
+
+	if (!sev_guest(kvm))
+		return -ENOTTY;
+
+	if (copy_from_user(&params, (void __user *)(uintptr_t)argp->data, sizeof(params)))
+		return -EFAULT;
+
+	return kvm_vm_do_hva_range_op(kvm, params.uaddr, params.uaddr + params.len,
+		sev_launch_update_gfn_handler, argp);
+}
+
 static int sev_es_sync_vmsa(struct vcpu_svm *svm)
 {
 	struct sev_es_save_area *save = svm->sev_es.vmsa;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index c860e6d6408d..5d0054e957b4 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -980,6 +980,8 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
 void kvm_exit(void);
 
 void kvm_get_kvm(struct kvm *kvm);
+int kvm_vm_set_region_attr(struct kvm *kvm, unsigned long gfn_start,
+	unsigned long gfn_end, bool priv_attr);
 bool kvm_get_kvm_safe(struct kvm *kvm);
 void kvm_put_kvm(struct kvm *kvm);
 bool file_is_kvm(struct file *file);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 16cb9ab59143..9463737c2172 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -981,7 +981,7 @@ static int kvm_vm_populate_private_mem(struct kvm *kvm, unsigned long gfn_start,
 	}
 
 	mutex_lock(&kvm->slots_lock);
-	for (gfn = gfn_start; gfn <= gfn_end; gfn++) {
+	for (gfn = gfn_start; gfn < gfn_end; gfn++) {
 		int order;
 		void *kvaddr;
 
@@ -1012,12 +1012,29 @@ static int kvm_vm_populate_private_mem(struct kvm *kvm, unsigned long gfn_start,
 }
 #endif
 
+int kvm_vm_set_region_attr(struct kvm *kvm, unsigned long gfn_start,
+	unsigned long gfn_end, bool priv_attr)
+{
+	int r;
+	void *entry;
+	unsigned long index;
+
+	entry = priv_attr ? xa_mk_value(KVM_MEM_ATTR_PRIVATE) : NULL;
+
+	for (index = gfn_start; index < gfn_end; index++) {
+		r = xa_err(xa_store(&kvm->mem_attr_array, index, entry,
+				GFP_KERNEL_ACCOUNT));
+		if (r)
+			break;
+	}
+
+	return r;
+}
+
 static int kvm_vm_ioctl_set_encrypted_region(struct kvm *kvm, unsigned int ioctl,
 					     struct kvm_enc_region *region)
 {
 	unsigned long start, end;
-	unsigned long index;
-	void *entry;
 	int r;
 
 	if (region->size == 0 || region->addr + region->size < region->addr)
@@ -1026,22 +1043,14 @@ static int kvm_vm_ioctl_set_encrypted_region(struct kvm *kvm, unsigned int ioctl
 		return -EINVAL;
 
 	start = region->addr >> PAGE_SHIFT;
-	end = (region->addr + region->size - 1) >> PAGE_SHIFT;
-
-	entry = ioctl == KVM_MEMORY_ENCRYPT_REG_REGION ?
-				xa_mk_value(KVM_MEM_ATTR_PRIVATE) : NULL;
-
-	for (index = start; index <= end; index++) {
-		r = xa_err(xa_store(&kvm->mem_attr_array, index, entry,
-				GFP_KERNEL_ACCOUNT));
-		if (r)
-			break;
-	}
+	end = (region->addr + region->size) >> PAGE_SHIFT;
+	r = kvm_vm_set_region_attr(kvm, start, end,
+		(ioctl == KVM_MEMORY_ENCRYPT_REG_REGION));
 
 	kvm_zap_gfn_range(kvm, start, end + 1);
 
 #ifdef CONFIG_HAVE_KVM_PRIVATE_MEM_TESTING
-	if (!kvm->vm_entry_attempted && (ioctl == KVM_MEMORY_ENCRYPT_REG_REGION))
+	if (!r && !kvm->vm_entry_attempted && (ioctl == KVM_MEMORY_ENCRYPT_REG_REGION))
 		r = kvm_vm_populate_private_mem(kvm, start, end);
 #endif
 
-- 
2.37.2.672.g94769d06f0-goog