Merge tag 'hyperv-next-signed-20230902' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull hyperv updates from Wei Liu:

 - Support for SEV-SNP guests on Hyper-V (Tianyu Lan)

 - Support for TDX guests on Hyper-V (Dexuan Cui)

 - Use SBRM API in Hyper-V balloon driver (Mitchell Levy)

 - Avoid dereferencing ACPI root object handle in VMBus driver (Maciej
   Szmigiero)

 - A few misecllaneous fixes (Jiapeng Chong, Nathan Chancellor, Saurabh
   Sengar)

* tag 'hyperv-next-signed-20230902' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (24 commits)
  x86/hyperv: Remove duplicate include
  x86/hyperv: Move the code in ivm.c around to avoid unnecessary ifdef's
  x86/hyperv: Remove hv_isolation_type_en_snp
  x86/hyperv: Use TDX GHCI to access some MSRs in a TDX VM with the paravisor
  Drivers: hv: vmbus: Bring the post_msg_page back for TDX VMs with the paravisor
  x86/hyperv: Introduce a global variable hyperv_paravisor_present
  Drivers: hv: vmbus: Support >64 VPs for a fully enlightened TDX/SNP VM
  x86/hyperv: Fix serial console interrupts for fully enlightened TDX guests
  Drivers: hv: vmbus: Support fully enlightened TDX guests
  x86/hyperv: Support hypercalls for fully enlightened TDX guests
  x86/hyperv: Add hv_isolation_type_tdx() to detect TDX guests
  x86/hyperv: Fix undefined reference to isolation_type_en_snp without CONFIG_HYPERV
  x86/hyperv: Add missing 'inline' to hv_snp_boot_ap() stub
  hv: hyperv.h: Replace one-element array with flexible-array member
  Drivers: hv: vmbus: Don't dereference ACPI root object handle
  x86/hyperv: Add hyperv-specific handling for VMMCALL under SEV-ES
  x86/hyperv: Add smp support for SEV-SNP guest
  clocksource: hyper-v: Mark hyperv tsc page unencrypted in sev-snp enlightened guest
  x86/hyperv: Use vmmcall to implement Hyper-V hypercall in sev-snp enlightened guest
  drivers: hv: Mark percpu hvcall input arg page unencrypted in SEV-SNP enlightened guest
  ...

6 files changed, 225 insertions, 66 deletions

diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index ebf15f31d97e..3cabeeabb1ca 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -98,6 +98,7 @@ int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
 	 */
 	if (version >= VERSION_WIN10_V5) {
 		msg->msg_sint = VMBUS_MESSAGE_SINT;
+		msg->msg_vtl = ms_hyperv.vtl;
 		vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4;
 	} else {
 		msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
@@ -482,10 +483,17 @@ void vmbus_set_event(struct vmbus_channel *channel)
 
 	++channel->sig_events;
 
-	if (hv_isolation_type_snp())
-		hv_ghcb_hypercall(HVCALL_SIGNAL_EVENT, &channel->sig_event,
-				NULL, sizeof(channel->sig_event));
-	else
+	if (ms_hyperv.paravisor_present) {
+		if (hv_isolation_type_snp())
+			hv_ghcb_hypercall(HVCALL_SIGNAL_EVENT, &channel->sig_event,
+					  NULL, sizeof(channel->sig_event));
+		else if (hv_isolation_type_tdx())
+			hv_tdx_hypercall(HVCALL_SIGNAL_EVENT | HV_HYPERCALL_FAST_BIT,
+					 channel->sig_event, 0);
+		else
+			WARN_ON_ONCE(1);
+	} else {
 		hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
+	}
 }
 EXPORT_SYMBOL_GPL(vmbus_set_event);
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index de6708dbe0df..51e5018ac9b2 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -20,6 +20,7 @@
 #include <linux/interrupt.h>
 #include <clocksource/hyperv_timer.h>
 #include <asm/mshyperv.h>
+#include <linux/set_memory.h>
 #include "hyperv_vmbus.h"
 
 /* The one and only */
@@ -56,20 +57,37 @@ int hv_post_message(union hv_connection_id connection_id,
 
 	local_irq_save(flags);
 
-	aligned_msg = *this_cpu_ptr(hyperv_pcpu_input_arg);
+	/*
+	 * A TDX VM with the paravisor must use the decrypted post_msg_page: see
+	 * the comment in struct hv_per_cpu_context. A SNP VM with the paravisor
+	 * can use the encrypted hyperv_pcpu_input_arg because it copies the
+	 * input into the GHCB page, which has been decrypted by the paravisor.
+	 */
+	if (hv_isolation_type_tdx() && ms_hyperv.paravisor_present)
+		aligned_msg = this_cpu_ptr(hv_context.cpu_context)->post_msg_page;
+	else
+		aligned_msg = *this_cpu_ptr(hyperv_pcpu_input_arg);
+
 	aligned_msg->connectionid = connection_id;
 	aligned_msg->reserved = 0;
 	aligned_msg->message_type = message_type;
 	aligned_msg->payload_size = payload_size;
 	memcpy((void *)aligned_msg->payload, payload, payload_size);
 
-	if (hv_isolation_type_snp())
-		status = hv_ghcb_hypercall(HVCALL_POST_MESSAGE,
-				(void *)aligned_msg, NULL,
-				sizeof(*aligned_msg));
-	else
+	if (ms_hyperv.paravisor_present) {
+		if (hv_isolation_type_tdx())
+			status = hv_tdx_hypercall(HVCALL_POST_MESSAGE,
+						  virt_to_phys(aligned_msg), 0);
+		else if (hv_isolation_type_snp())
+			status = hv_ghcb_hypercall(HVCALL_POST_MESSAGE,
+						   aligned_msg, NULL,
+						   sizeof(*aligned_msg));
+		else
+			status = HV_STATUS_INVALID_PARAMETER;
+	} else {
 		status = hv_do_hypercall(HVCALL_POST_MESSAGE,
 				aligned_msg, NULL);
+	}
 
 	local_irq_restore(flags);
 
@@ -78,7 +96,7 @@ int hv_post_message(union hv_connection_id connection_id,
 
 int hv_synic_alloc(void)
 {
-	int cpu;
+	int cpu, ret = -ENOMEM;
 	struct hv_per_cpu_context *hv_cpu;
 
 	/*
@@ -104,11 +122,29 @@ int hv_synic_alloc(void)
 		tasklet_init(&hv_cpu->msg_dpc,
 			     vmbus_on_msg_dpc, (unsigned long) hv_cpu);
 
+		if (ms_hyperv.paravisor_present && hv_isolation_type_tdx()) {
+			hv_cpu->post_msg_page = (void *)get_zeroed_page(GFP_ATOMIC);
+			if (hv_cpu->post_msg_page == NULL) {
+				pr_err("Unable to allocate post msg page\n");
+				goto err;
+			}
+
+			ret = set_memory_decrypted((unsigned long)hv_cpu->post_msg_page, 1);
+			if (ret) {
+				pr_err("Failed to decrypt post msg page: %d\n", ret);
+				/* Just leak the page, as it's unsafe to free the page. */
+				hv_cpu->post_msg_page = NULL;
+				goto err;
+			}
+
+			memset(hv_cpu->post_msg_page, 0, PAGE_SIZE);
+		}
+
 		/*
 		 * Synic message and event pages are allocated by paravisor.
 		 * Skip these pages allocation here.
 		 */
-		if (!hv_isolation_type_snp() && !hv_root_partition) {
+		if (!ms_hyperv.paravisor_present && !hv_root_partition) {
 			hv_cpu->synic_message_page =
 				(void *)get_zeroed_page(GFP_ATOMIC);
 			if (hv_cpu->synic_message_page == NULL) {
@@ -120,29 +156,96 @@ int hv_synic_alloc(void)
 				(void *)get_zeroed_page(GFP_ATOMIC);
 			if (hv_cpu->synic_event_page == NULL) {
 				pr_err("Unable to allocate SYNIC event page\n");
+
+				free_page((unsigned long)hv_cpu->synic_message_page);
+				hv_cpu->synic_message_page = NULL;
 				goto err;
 			}
 		}
+
+		if (!ms_hyperv.paravisor_present &&
+		    (hv_isolation_type_snp() || hv_isolation_type_tdx())) {
+			ret = set_memory_decrypted((unsigned long)
+				hv_cpu->synic_message_page, 1);
+			if (ret) {
+				pr_err("Failed to decrypt SYNIC msg page: %d\n", ret);
+				hv_cpu->synic_message_page = NULL;
+
+				/*
+				 * Free the event page here so that hv_synic_free()
+				 * won't later try to re-encrypt it.
+				 */
+				free_page((unsigned long)hv_cpu->synic_event_page);
+				hv_cpu->synic_event_page = NULL;
+				goto err;
+			}
+
+			ret = set_memory_decrypted((unsigned long)
+				hv_cpu->synic_event_page, 1);
+			if (ret) {
+				pr_err("Failed to decrypt SYNIC event page: %d\n", ret);
+				hv_cpu->synic_event_page = NULL;
+				goto err;
+			}
+
+			memset(hv_cpu->synic_message_page, 0, PAGE_SIZE);
+			memset(hv_cpu->synic_event_page, 0, PAGE_SIZE);
+		}
 	}
 
 	return 0;
+
 err:
 	/*
 	 * Any memory allocations that succeeded will be freed when
 	 * the caller cleans up by calling hv_synic_free()
 	 */
-	return -ENOMEM;
+	return ret;
 }
 
 
 void hv_synic_free(void)
 {
-	int cpu;
+	int cpu, ret;
 
 	for_each_present_cpu(cpu) {
 		struct hv_per_cpu_context *hv_cpu
 			= per_cpu_ptr(hv_context.cpu_context, cpu);
 
+		/* It's better to leak the page if the encryption fails. */
+		if (ms_hyperv.paravisor_present && hv_isolation_type_tdx()) {
+			if (hv_cpu->post_msg_page) {
+				ret = set_memory_encrypted((unsigned long)
+					hv_cpu->post_msg_page, 1);
+				if (ret) {
+					pr_err("Failed to encrypt post msg page: %d\n", ret);
+					hv_cpu->post_msg_page = NULL;
+				}
+			}
+		}
+
+		if (!ms_hyperv.paravisor_present &&
+		    (hv_isolation_type_snp() || hv_isolation_type_tdx())) {
+			if (hv_cpu->synic_message_page) {
+				ret = set_memory_encrypted((unsigned long)
+					hv_cpu->synic_message_page, 1);
+				if (ret) {
+					pr_err("Failed to encrypt SYNIC msg page: %d\n", ret);
+					hv_cpu->synic_message_page = NULL;
+				}
+			}
+
+			if (hv_cpu->synic_event_page) {
+				ret = set_memory_encrypted((unsigned long)
+					hv_cpu->synic_event_page, 1);
+				if (ret) {
+					pr_err("Failed to encrypt SYNIC event page: %d\n", ret);
+					hv_cpu->synic_event_page = NULL;
+				}
+			}
+		}
+
+		free_page((unsigned long)hv_cpu->post_msg_page);
 		free_page((unsigned long)hv_cpu->synic_event_page);
 		free_page((unsigned long)hv_cpu->synic_message_page);
 	}
@@ -170,7 +273,7 @@ void hv_synic_enable_regs(unsigned int cpu)
 	simp.as_uint64 = hv_get_register(HV_REGISTER_SIMP);
 	simp.simp_enabled = 1;
 
-	if (hv_isolation_type_snp() || hv_root_partition) {
+	if (ms_hyperv.paravisor_present || hv_root_partition) {
 		/* Mask out vTOM bit. ioremap_cache() maps decrypted */
 		u64 base = (simp.base_simp_gpa << HV_HYP_PAGE_SHIFT) &
 				~ms_hyperv.shared_gpa_boundary;
@@ -189,7 +292,7 @@ void hv_synic_enable_regs(unsigned int cpu)
 	siefp.as_uint64 = hv_get_register(HV_REGISTER_SIEFP);
 	siefp.siefp_enabled = 1;
 
-	if (hv_isolation_type_snp() || hv_root_partition) {
+	if (ms_hyperv.paravisor_present || hv_root_partition) {
 		/* Mask out vTOM bit. ioremap_cache() maps decrypted */
 		u64 base = (siefp.base_siefp_gpa << HV_HYP_PAGE_SHIFT) &
 				~ms_hyperv.shared_gpa_boundary;
@@ -272,7 +375,7 @@ void hv_synic_disable_regs(unsigned int cpu)
 	 * addresses.
 	 */
 	simp.simp_enabled = 0;
-	if (hv_isolation_type_snp() || hv_root_partition) {
+	if (ms_hyperv.paravisor_present || hv_root_partition) {
 		iounmap(hv_cpu->synic_message_page);
 		hv_cpu->synic_message_page = NULL;
 	} else {
@@ -284,7 +387,7 @@ void hv_synic_disable_regs(unsigned int cpu)
 	siefp.as_uint64 = hv_get_register(HV_REGISTER_SIEFP);
 	siefp.siefp_enabled = 0;
 
-	if (hv_isolation_type_snp() || hv_root_partition) {
+	if (ms_hyperv.paravisor_present || hv_root_partition) {
 		iounmap(hv_cpu->synic_event_page);
 		hv_cpu->synic_event_page = NULL;
 	} else {
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index 0d7a3ba66396..e000fa3b9f97 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -8,6 +8,7 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <linux/cleanup.h>
 #include <linux/kernel.h>
 #include <linux/jiffies.h>
 #include <linux/mman.h>
@@ -646,7 +647,7 @@ static int hv_memory_notifier(struct notifier_block *nb, unsigned long val,
 			      void *v)
 {
 	struct memory_notify *mem = (struct memory_notify *)v;
-	unsigned long flags, pfn_count;
+	unsigned long pfn_count;
 
 	switch (val) {
 	case MEM_ONLINE:
@@ -655,21 +656,22 @@ static int hv_memory_notifier(struct notifier_block *nb, unsigned long val,
 		break;
 
 	case MEM_OFFLINE:
-		spin_lock_irqsave(&dm_device.ha_lock, flags);
-		pfn_count = hv_page_offline_check(mem->start_pfn,
-						  mem->nr_pages);
-		if (pfn_count <= dm_device.num_pages_onlined) {
-			dm_device.num_pages_onlined -= pfn_count;
-		} else {
-			/*
-			 * We're offlining more pages than we managed to online.
-			 * This is unexpected. In any case don't let
-			 * num_pages_onlined wrap around zero.
-			 */
-			WARN_ON_ONCE(1);
-			dm_device.num_pages_onlined = 0;
+		scoped_guard(spinlock_irqsave, &dm_device.ha_lock) {
+			pfn_count = hv_page_offline_check(mem->start_pfn,
+							  mem->nr_pages);
+			if (pfn_count <= dm_device.num_pages_onlined) {
+				dm_device.num_pages_onlined -= pfn_count;
+			} else {
+				/*
+				 * We're offlining more pages than we
+				 * managed to online. This is
+				 * unexpected. In any case don't let
+				 * num_pages_onlined wrap around zero.
+				 */
+				WARN_ON_ONCE(1);
+				dm_device.num_pages_onlined = 0;
+			}
 		}
-		spin_unlock_irqrestore(&dm_device.ha_lock, flags);
 		break;
 	case MEM_GOING_ONLINE:
 	case MEM_GOING_OFFLINE:
@@ -721,24 +723,23 @@ static void hv_mem_hot_add(unsigned long start, unsigned long size,
 	unsigned long start_pfn;
 	unsigned long processed_pfn;
 	unsigned long total_pfn = pfn_count;
-	unsigned long flags;
 
 	for (i = 0; i < (size/HA_CHUNK); i++) {
 		start_pfn = start + (i * HA_CHUNK);
 
-		spin_lock_irqsave(&dm_device.ha_lock, flags);
-		has->ha_end_pfn +=  HA_CHUNK;
+		scoped_guard(spinlock_irqsave, &dm_device.ha_lock) {
+			has->ha_end_pfn +=  HA_CHUNK;
 
-		if (total_pfn > HA_CHUNK) {
-			processed_pfn = HA_CHUNK;
-			total_pfn -= HA_CHUNK;
-		} else {
-			processed_pfn = total_pfn;
-			total_pfn = 0;
-		}
+			if (total_pfn > HA_CHUNK) {
+				processed_pfn = HA_CHUNK;
+				total_pfn -= HA_CHUNK;
+			} else {
+				processed_pfn = total_pfn;
+				total_pfn = 0;
+			}
 
-		has->covered_end_pfn +=  processed_pfn;
-		spin_unlock_irqrestore(&dm_device.ha_lock, flags);
+			has->covered_end_pfn +=  processed_pfn;
+		}
 
 		reinit_completion(&dm_device.ol_waitevent);
 
@@ -758,10 +759,10 @@ static void hv_mem_hot_add(unsigned long start, unsigned long size,
 				 */
 				do_hot_add = false;
 			}
-			spin_lock_irqsave(&dm_device.ha_lock, flags);
-			has->ha_end_pfn -= HA_CHUNK;
-			has->covered_end_pfn -=  processed_pfn;
-			spin_unlock_irqrestore(&dm_device.ha_lock, flags);
+			scoped_guard(spinlock_irqsave, &dm_device.ha_lock) {
+				has->ha_end_pfn -= HA_CHUNK;
+				has->covered_end_pfn -=  processed_pfn;
+			}
 			break;
 		}
 
@@ -781,10 +782,9 @@ static void hv_mem_hot_add(unsigned long start, unsigned long size,
 static void hv_online_page(struct page *pg, unsigned int order)
 {
 	struct hv_hotadd_state *has;
-	unsigned long flags;
 	unsigned long pfn = page_to_pfn(pg);
 
-	spin_lock_irqsave(&dm_device.ha_lock, flags);
+	guard(spinlock_irqsave)(&dm_device.ha_lock);
 	list_for_each_entry(has, &dm_device.ha_region_list, list) {
 		/* The page belongs to a different HAS. */
 		if ((pfn < has->start_pfn) ||
@@ -794,7 +794,6 @@ static void hv_online_page(struct page *pg, unsigned int order)
 		hv_bring_pgs_online(has, pfn, 1UL << order);
 		break;
 	}
-	spin_unlock_irqrestore(&dm_device.ha_lock, flags);
 }
 
 static int pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt)
@@ -803,9 +802,8 @@ static int pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt)
 	struct hv_hotadd_gap *gap;
 	unsigned long residual, new_inc;
 	int ret = 0;
-	unsigned long flags;
 
-	spin_lock_irqsave(&dm_device.ha_lock, flags);
+	guard(spinlock_irqsave)(&dm_device.ha_lock);
 	list_for_each_entry(has, &dm_device.ha_region_list, list) {
 		/*
 		 * If the pfn range we are dealing with is not in the current
@@ -852,7 +850,6 @@ static int pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt)
 		ret = 1;
 		break;
 	}
-	spin_unlock_irqrestore(&dm_device.ha_lock, flags);
 
 	return ret;
 }
@@ -947,7 +944,6 @@ static unsigned long process_hot_add(unsigned long pg_start,
 {
 	struct hv_hotadd_state *ha_region = NULL;
 	int covered;
-	unsigned long flags;
 
 	if (pfn_cnt == 0)
 		return 0;
@@ -979,9 +975,9 @@ static unsigned long process_hot_add(unsigned long pg_start,
 		ha_region->covered_end_pfn = pg_start;
 		ha_region->end_pfn = rg_start + rg_size;
 
-		spin_lock_irqsave(&dm_device.ha_lock, flags);
-		list_add_tail(&ha_region->list, &dm_device.ha_region_list);
-		spin_unlock_irqrestore(&dm_device.ha_lock, flags);
+		scoped_guard(spinlock_irqsave, &dm_device.ha_lock) {
+			list_add_tail(&ha_region->list, &dm_device.ha_region_list);
+		}
 	}
 
 do_pg_range:
@@ -2047,7 +2043,6 @@ static void balloon_remove(struct hv_device *dev)
 	struct hv_dynmem_device *dm = hv_get_drvdata(dev);
 	struct hv_hotadd_state *has, *tmp;
 	struct hv_hotadd_gap *gap, *tmp_gap;
-	unsigned long flags;
 
 	if (dm->num_pages_ballooned != 0)
 		pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned);
@@ -2073,7 +2068,7 @@ static void balloon_remove(struct hv_device *dev)
 #endif
 	}
 
-	spin_lock_irqsave(&dm_device.ha_lock, flags);
+	guard(spinlock_irqsave)(&dm_device.ha_lock);
 	list_for_each_entry_safe(has, tmp, &dm->ha_region_list, list) {
 		list_for_each_entry_safe(gap, tmp_gap, &has->gap_list, list) {
 			list_del(&gap->list);
@@ -2082,7 +2077,6 @@ static void balloon_remove(struct hv_device *dev)
 		list_del(&has->list);
 		kfree(has);
 	}
-	spin_unlock_irqrestore(&dm_device.ha_lock, flags);
 }
 
 static int balloon_suspend(struct hv_device *hv_dev)
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index 6a2258fef1fe..ccad7bca3fd3 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -24,6 +24,7 @@
 #include <linux/kmsg_dump.h>
 #include <linux/slab.h>
 #include <linux/dma-map-ops.h>
+#include <linux/set_memory.h>
 #include <asm/hyperv-tlfs.h>
 #include <asm/mshyperv.h>
 
@@ -359,6 +360,8 @@ int hv_common_cpu_init(unsigned int cpu)
 	u64 msr_vp_index;
 	gfp_t flags;
 	int pgcount = hv_root_partition ? 2 : 1;
+	void *mem;
+	int ret;
 
 	/* hv_cpu_init() can be called with IRQs disabled from hv_resume() */
 	flags = irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL;
@@ -370,14 +373,41 @@ int hv_common_cpu_init(unsigned int cpu)
 	 * allocated if this CPU was previously online and then taken offline
 	 */
 	if (!*inputarg) {
-		*inputarg = kmalloc(pgcount * HV_HYP_PAGE_SIZE, flags);
-		if (!(*inputarg))
+		mem = kmalloc(pgcount * HV_HYP_PAGE_SIZE, flags);
+		if (!mem)
 			return -ENOMEM;
 
 		if (hv_root_partition) {
 			outputarg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
-			*outputarg = (char *)(*inputarg) + HV_HYP_PAGE_SIZE;
+			*outputarg = (char *)mem + HV_HYP_PAGE_SIZE;
+		}
+
+		if (!ms_hyperv.paravisor_present &&
+		    (hv_isolation_type_snp() || hv_isolation_type_tdx())) {
+			ret = set_memory_decrypted((unsigned long)mem, pgcount);
+			if (ret) {
+				/* It may be unsafe to free 'mem' */
+				return ret;
+			}
+
+			memset(mem, 0x00, pgcount * HV_HYP_PAGE_SIZE);
 		}
+
+		/*
+		 * In a fully enlightened TDX/SNP VM with more than 64 VPs, if
+		 * hyperv_pcpu_input_arg is not NULL, set_memory_decrypted() ->
+		 * ... -> cpa_flush()-> ... -> __send_ipi_mask_ex() tries to
+		 * use hyperv_pcpu_input_arg as the hypercall input page, which
+		 * must be a decrypted page in such a VM, but the page is still
+		 * encrypted before set_memory_decrypted() returns. Fix this by
+		 * setting *inputarg after the above set_memory_decrypted(): if
+		 * hyperv_pcpu_input_arg is NULL, __send_ipi_mask_ex() returns
+		 * HV_STATUS_INVALID_PARAMETER immediately, and the function
+		 * hv_send_ipi_mask() falls back to orig_apic.send_IPI_mask(),
+		 * which may be slightly slower than the hypercall, but still
+		 * works correctly in such a VM.
+		 */
+		*inputarg = mem;
 	}
 
 	msr_vp_index = hv_get_register(HV_REGISTER_VP_INDEX);
@@ -502,6 +532,12 @@ bool __weak hv_isolation_type_snp(void)
 }
 EXPORT_SYMBOL_GPL(hv_isolation_type_snp);
 
+bool __weak hv_isolation_type_tdx(void)
+{
+	return false;
+}
+EXPORT_SYMBOL_GPL(hv_isolation_type_tdx);
+
 void __weak hv_setup_vmbus_handler(void (*handler)(void))
 {
 }
@@ -542,3 +578,9 @@ u64 __weak hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_s
 	return HV_STATUS_INVALID_PARAMETER;
 }
 EXPORT_SYMBOL_GPL(hv_ghcb_hypercall);
+
+u64 __weak hv_tdx_hypercall(u64 control, u64 param1, u64 param2)
+{
+	return HV_STATUS_INVALID_PARAMETER;
+}
+EXPORT_SYMBOL_GPL(hv_tdx_hypercall);
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 55f2086841ae..f6b1e710f805 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -124,6 +124,17 @@ struct hv_per_cpu_context {
 	void *synic_event_page;
 
 	/*
+	 * The page is only used in hv_post_message() for a TDX VM (with the
+	 * paravisor) to post a messages to Hyper-V: when such a VM calls
+	 * HVCALL_POST_MESSAGE, it can't use the hyperv_pcpu_input_arg (which
+	 * is encrypted in such a VM) as the hypercall input page, because
+	 * the input page for HVCALL_POST_MESSAGE must be decrypted in such a
+	 * VM, so post_msg_page (which is decrypted in hv_synic_alloc()) is
+	 * introduced for this purpose. See hyperv_init() for more comments.
+	 */
+	void *post_msg_page;
+
+	/*
 	 * Starting with win8, we can take channel interrupts on any CPU;
 	 * we will manage the tasklet that handles events messages on a per CPU
 	 * basis.
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 67f95a29aeca..edbb38f6956b 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2287,7 +2287,8 @@ static int vmbus_acpi_add(struct platform_device *pdev)
 	 * Some ancestor of the vmbus acpi device (Gen1 or Gen2
 	 * firmware) is the VMOD that has the mmio ranges. Get that.
 	 */
-	for (ancestor = acpi_dev_parent(device); ancestor;
+	for (ancestor = acpi_dev_parent(device);
+	     ancestor && ancestor->handle != ACPI_ROOT_OBJECT;
 	     ancestor = acpi_dev_parent(ancestor)) {
 		result = acpi_walk_resources(ancestor->handle, METHOD_NAME__CRS,
 					     vmbus_walk_resources, NULL);