[PATCH Part2 v5 25/45] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_UPDATE command

@@ -478,6 +478,35 @@ Returns: 0 on success, -negative on error
 
 See the SEV-SNP specification for further detail on the launch input.
 
+20. KVM_SNP_LAUNCH_UPDATE
+-------------------------
+
+The KVM_SNP_LAUNCH_UPDATE is used for encrypting a memory region. It also
+calculates a measurement of the memory contents. The measurement is a signature
+of the memory contents that can be sent to the guest owner as an attestation
+that the memory was encrypted correctly by the firmware.
+
+Parameters (in): struct  kvm_snp_launch_update
+
+Returns: 0 on success, -negative on error
+
+::
+
+        struct kvm_sev_snp_launch_update {
+                __u64 start_gfn;        /* Guest page number to start from. */
+                __u64 uaddr;            /* userspace address need to be encrypted */
+                __u32 len;              /* length of memory region */
+                __u8 imi_page;          /* 1 if memory is part of the IMI */
+                __u8 page_type;         /* page type */
+                __u8 vmpl3_perms;       /* VMPL3 permission mask */
+                __u8 vmpl2_perms;       /* VMPL2 permission mask */
+                __u8 vmpl1_perms;       /* VMPL1 permission mask */
+        };
+
+See the SEV-SNP spec for further details on how to build the VMPL permission
+mask and page type.
+
+
 References
 ==========
 

@@ -17,6 +17,7 @@
 #include <linux/misc_cgroup.h>
 #include <linux/processor.h>
 #include <linux/trace_events.h>
+#include <linux/sev.h>
 #include <asm/fpu/internal.h>
 
 #include <asm/pkru.h>

@@ -227,6 +228,49 @@ static void sev_decommission(unsigned int handle)
 	sev_guest_decommission(&decommission, NULL);
 }
 
+static inline void snp_leak_pages(u64 pfn, enum pg_level level)
+{
+	unsigned int npages = page_level_size(level) >> PAGE_SHIFT;
+
+	WARN(1, "psc failed pfn 0x%llx pages %d (leaking)\n", pfn, npages);
+
+	while (npages) {
+		memory_failure(pfn, 0);
+		dump_rmpentry(pfn);
+		npages--;
+		pfn++;
+	}
+}
+
+static int snp_page_reclaim(u64 pfn)
+{
+	struct sev_data_snp_page_reclaim data = {0};
+	int err, rc;
+
+	data.paddr = __sme_set(pfn << PAGE_SHIFT);
+	rc = snp_guest_page_reclaim(&data, &err);
+	if (rc) {
+		/*
+		 * If the reclaim failed, then page is no longer safe
+		 * to use.
+		 */
+		snp_leak_pages(pfn, PG_LEVEL_4K);
+	}
+
+	return rc;
+}
+
+static int host_rmp_make_shared(u64 pfn, enum pg_level level, bool leak)
+{
+	int rc;
+
+	rc = rmp_make_shared(pfn, level);
+	if (rc && leak)
+		snp_leak_pages(pfn, level);
+
+	return rc;
+}
+
 static void sev_unbind_asid(struct kvm *kvm, unsigned int handle)
 {
 	struct sev_data_deactivate deactivate;

@@ -1620,6 +1664,123 @@ static int snp_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	return rc;
 }
 
+static bool is_hva_registered(struct kvm *kvm, hva_t hva, size_t len)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+	struct list_head *head = &sev->regions_list;
+	struct enc_region *i;
+
+	lockdep_assert_held(&kvm->lock);
+
+	list_for_each_entry(i, head, list) {
+		u64 start = i->uaddr;
+		u64 end = start + i->size;
+
+		if (start <= hva && end >= (hva + len))
+			return true;
+	}
+
+	return false;
+}
+
+static int snp_launch_update(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+	struct sev_data_snp_launch_update data = {0};
+	struct kvm_sev_snp_launch_update params;
+	unsigned long npages, pfn, n = 0;
+	int *error = &argp->error;
+	struct page **inpages;
+	int ret, i, level;
+	u64 gfn;
+
+	if (!sev_snp_guest(kvm))
+		return -ENOTTY;
+
+	if (!sev->snp_context)
+		return -EINVAL;
+
+	if (copy_from_user(&params, (void __user *)(uintptr_t)argp->data, sizeof(params)))
+		return -EFAULT;
+
+	/* Verify that the specified address range is registered. */
+	if (!is_hva_registered(kvm, params.uaddr, params.len))
+		return -EINVAL;
+
+	/*
+	 * The userspace memory is already locked so technically we don't
+	 * need to lock it again. Later part of the function needs to know
+	 * pfn so call the sev_pin_memory() so that we can get the list of
+	 * pages to iterate through.
+	 */
+	inpages = sev_pin_memory(kvm, params.uaddr, params.len, &npages, 1);
+	if (!inpages)
+		return -ENOMEM;
+
+	/*
+	 * Verify that all the pages are marked shared in the RMP table before
+	 * going further. This is avoid the cases where the userspace may try
+	 * updating the same page twice.
+	 */
+	for (i = 0; i < npages; i++) {
+		if (snp_lookup_rmpentry(page_to_pfn(inpages[i]), &level) != 0) {
+			sev_unpin_memory(kvm, inpages, npages);
+			return -EFAULT;
+		}
+	}
+
+	gfn = params.start_gfn;
+	level = PG_LEVEL_4K;
+	data.gctx_paddr = __psp_pa(sev->snp_context);
+
+	for (i = 0; i < npages; i++) {
+		pfn = page_to_pfn(inpages[i]);
+
+		ret = rmp_make_private(pfn, gfn << PAGE_SHIFT, level, sev_get_asid(kvm), true);
+		if (ret) {
+			ret = -EFAULT;
+			goto e_unpin;
+		}
+
+		n++;
+		data.address = __sme_page_pa(inpages[i]);
+		data.page_size = X86_TO_RMP_PG_LEVEL(level);
+		data.page_type = params.page_type;
+		data.vmpl3_perms = params.vmpl3_perms;
+		data.vmpl2_perms = params.vmpl2_perms;
+		data.vmpl1_perms = params.vmpl1_perms;
+		ret = __sev_issue_cmd(argp->sev_fd, SEV_CMD_SNP_LAUNCH_UPDATE, &data, error);
+		if (ret) {
+			/*
+			 * If the command failed then need to reclaim the page.
+			 */
+			snp_page_reclaim(pfn);
+			goto e_unpin;
+		}
+
+		gfn++;
+	}
+
+e_unpin:
+	/* Content of memory is updated, mark pages dirty */
+	for (i = 0; i < n; i++) {
+		set_page_dirty_lock(inpages[i]);
+		mark_page_accessed(inpages[i]);
+
+		/*
+		 * If its an error, then update RMP entry to change page ownership
+		 * to the hypervisor.
+		 */
+		if (ret)
+			host_rmp_make_shared(pfn, level, true);
+	}
+
+	/* Unlock the user pages */
+	sev_unpin_memory(kvm, inpages, npages);
+
+	return ret;
+}
+
 int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 {
 	struct kvm_sev_cmd sev_cmd;

@@ -1712,6 +1873,9 @@ int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 	case KVM_SEV_SNP_LAUNCH_START:
 		r = snp_launch_start(kvm, &sev_cmd);
 		break;
+	case KVM_SEV_SNP_LAUNCH_UPDATE:
+		r = snp_launch_update(kvm, &sev_cmd);
+		break;
 	default:
 		r = -EINVAL;
 		goto out;

@@ -1794,6 +1958,29 @@ find_enc_region(struct kvm *kvm, struct kvm_enc_region *range)
 static void __unregister_enc_region_locked(struct kvm *kvm,
 					   struct enc_region *region)
 {
+	unsigned long i, pfn;
+	int level;
+
+	/*
+	 * The guest memory pages are assigned in the RMP table. Unassign it
+	 * before releasing the memory.
+	 */
+	if (sev_snp_guest(kvm)) {
+		for (i = 0; i < region->npages; i++) {
+			pfn = page_to_pfn(region->pages[i]);
+
+			if (!snp_lookup_rmpentry(pfn, &level))
+				continue;
+
+			cond_resched();
+
+			if (level > PG_LEVEL_4K)
+				pfn &= ~(KVM_PAGES_PER_HPAGE(PG_LEVEL_2M) - 1);
+
+			host_rmp_make_shared(pfn, level, true);
+		}
+	}
+
 	sev_unpin_memory(kvm, region->pages, region->npages);
 	list_del(&region->list);
 	kfree(region);

@@ -1715,6 +1715,7 @@ enum sev_cmd_id {
 	/* SNP specific commands */
 	KVM_SEV_SNP_INIT,
 	KVM_SEV_SNP_LAUNCH_START,
+	KVM_SEV_SNP_LAUNCH_UPDATE,
 
 	KVM_SEV_NR_MAX,
 };

@@ -1831,6 +1832,24 @@ struct kvm_sev_snp_launch_start {
 	__u8 pad[6];
 };
 
+#define KVM_SEV_SNP_PAGE_TYPE_NORMAL		0x1
+#define KVM_SEV_SNP_PAGE_TYPE_VMSA		0x2
+#define KVM_SEV_SNP_PAGE_TYPE_ZERO		0x3
+#define KVM_SEV_SNP_PAGE_TYPE_UNMEASURED	0x4
+#define KVM_SEV_SNP_PAGE_TYPE_SECRETS		0x5
+#define KVM_SEV_SNP_PAGE_TYPE_CPUID		0x6
+
+struct kvm_sev_snp_launch_update {
+	__u64 start_gfn;
+	__u64 uaddr;
+	__u32 len;
+	__u8 imi_page;
+	__u8 page_type;
+	__u8 vmpl3_perms;
+	__u8 vmpl2_perms;
+	__u8 vmpl1_perms;
+};
+
 #define KVM_DEV_ASSIGN_ENABLE_IOMMU	(1 << 0)
 #define KVM_DEV_ASSIGN_PCI_2_3		(1 << 1)
 #define KVM_DEV_ASSIGN_MASK_INTX	(1 << 2)