[PATCH RFC v7 10/64] KVM: SEV: Populate private memory fd during LAUNCH_UPDATE_DATA

[Michael Roth]

From: Vishal Annapurve <vannapurve@xxxxxxxxxx>

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@xxxxxxxxxx>
[mdr: use gfn_to_hva_memslot_prot() for shared GFN handler to deal with
      read-only slots for ROMs]
Signed-off-by: Michael Roth <michael.roth@xxxxxxx>
---
 arch/x86/kvm/svm/sev.c   | 99 ++++++++++++++++++++++++++++++++++++----
 include/linux/kvm_host.h |  1 +
 virt/kvm/kvm_main.c      | 27 ++++++++---
 3 files changed, 111 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 69dbf17f0d6a..a7e4e3005786 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -493,23 +493,26 @@ 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)
+static 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_prot(range->slot, range->start, NULL);
+	pr_debug("%s: shared GFN: %llx, slot.id: %d, slot.base_gfn: %llx, slot.userspace_addr: %lx, slot.flags: %x, vaddr: %lx\n",
+		 __func__, range->start, range->slot->id, range->slot->base_gfn,
+		 range->slot->userspace_addr, range->slot->flags, vaddr);
+	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. */
@@ -561,6 +564,84 @@ static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	return ret;
 }
 
+static 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_restricted_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%llx\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%x\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_release_pfn_clean(pfn);
+	}
+	kvm_vm_set_region_attr(kvm, range->start, range->end,
+		true /* priv_attr */);
+
+e_ret:
+	return ret;
+}
+
+static 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 21a539ab17f6..33fa0b1435d3 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -973,6 +973,7 @@ 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, gfn_t start, gfn_t end, u64 attributes);
 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 4ff7adaf6c56..1343070657d1 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -747,6 +747,7 @@ int kvm_vm_do_hva_range_op(struct kvm *kvm, unsigned long hva_start,
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(kvm_vm_do_hva_range_op);
 
 static __always_inline int kvm_handle_hva_range(struct mmu_notifier *mn,
 						unsigned long start,
@@ -2595,12 +2596,28 @@ static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end,
 		kvm_flush_remote_tlbs(kvm);
 }
 
+int kvm_vm_set_region_attr(struct kvm *kvm, gfn_t start, gfn_t end,
+			   u64 attributes)
+{
+	gfn_t index;
+	void *entry;
+
+	entry = attributes ? xa_mk_value(attributes) : NULL;
+
+	for (index = start; index < end; index++)
+		if (xa_err(xa_store(&kvm->mem_attr_array, index, entry,
+				    GFP_KERNEL_ACCOUNT)))
+			break;
+
+	return index;
+}
+EXPORT_SYMBOL_GPL(kvm_vm_set_region_attr);
+
 static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
 					   struct kvm_memory_attributes *attrs)
 {
 	gfn_t start, end;
 	unsigned long i;
-	void *entry;
 	int idx;
 	u64 supported_attrs = kvm_supported_mem_attributes(kvm);
 
@@ -2617,8 +2634,6 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
 	start = attrs->address >> PAGE_SHIFT;
 	end = (attrs->address + attrs->size - 1 + PAGE_SIZE) >> PAGE_SHIFT;
 
-	entry = attrs->attributes ? xa_mk_value(attrs->attributes) : NULL;
-
 	if (kvm_arch_has_private_mem(kvm)) {
 		KVM_MMU_LOCK(kvm);
 		kvm_mmu_invalidate_begin(kvm);
@@ -2627,10 +2642,7 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
 	}
 
 	mutex_lock(&kvm->lock);
-	for (i = start; i < end; i++)
-		if (xa_err(xa_store(&kvm->mem_attr_array, i, entry,
-				    GFP_KERNEL_ACCOUNT)))
-			break;
+	i = kvm_vm_set_region_attr(kvm, start, end, attrs->attributes);
 	mutex_unlock(&kvm->lock);
 
 	if (kvm_arch_has_private_mem(kvm)) {
@@ -2793,6 +2805,7 @@ unsigned long gfn_to_hva_memslot_prot(struct kvm_memory_slot *slot,
 
 	return hva;
 }
+EXPORT_SYMBOL_GPL(gfn_to_hva_memslot_prot);
 
 unsigned long gfn_to_hva_prot(struct kvm *kvm, gfn_t gfn, bool *writable)
 {
-- 
2.25.1