[RFC V2 PATCH 00/12] x86/Hyper-V: Add Hyper-V Isolation VM support

[RFC V2 PATCH 00/12] x86/Hyper-V: Add Hyper-V Isolation VM support

[Tianyu Lan]

From: Tianyu Lan <Tianyu.Lan@microsoft.com>


Hyper-V provides two kinds of Isolation VMs. VBS(Virtualization-based
security) and AMD SEV-SNP unenlightened Isolation VMs. This patchset
is to add support for these Isolation VM support in Linux.

The memory of these vms are encrypted and host can't access guest
memory directly. Hyper-V provides new host visibility hvcall and
the guest needs to call new hvcall to mark memory visible to host
before sharing memory with host. For security, all network/storage
stack memory should not be shared with host and so there is bounce
buffer requests.

Vmbus channel ring buffer already plays bounce buffer role because
all data from/to host needs to copy from/to between the ring buffer
and IO stack memory. So mark vmbus channel ring buffer visible to
host.

There are two exceptions - packets sent by vmbus_sendpacket_
pagebuffer() and vmbus_sendpacket_mpb_desc(). These packets
contains IO stack memory address and host will access these memory.
So add Hyper-V DMA Ops and use DMA API in the netvsc and storvsc
drivers to allocate bounce buffer via swiotlb interface.

For SNP isolation VM, guest needs to access the shared memory via
extra address space which is specified by Hyper-V CPUID HYPERV_CPUID_
ISOLATION_CONFIG. The access physical address of the shared memory
should be bounce buffer memory GPA plus with shared_gpa_boundary
reported by CPUID.

Change since v1:
       * Add DMA API support in the netvsc and storvsc driver.
       * Add Hyper-V DMA ops.
       * Add static branch for the check of isolation type snp.
       * Fix some code style comments.

Tianyu Lan (12):
  x86/HV: Initialize GHCB page in Isolation VM
  x86/HV: Initialize shared memory boundary in Isolation VM
  x86/Hyper-V: Add new hvcall guest address host visibility support
  HV: Add Write/Read MSR registers via ghcb
  HV: Add ghcb hvcall support for SNP VM
  HV/Vmbus: Add SNP support for VMbus channel initiate message
  HV/Vmbus: Initialize VMbus ring buffer for Isolation VM
  UIO/Hyper-V: Not load UIO HV driver in the isolation VM.
  swiotlb: Add bounce buffer remap address setting function
  HV/IOMMU: Add Hyper-V dma ops support
  HV/Netvsc: Add Isolation VM support for netvsc driver
  HV/Storvsc: Add Isolation VM support for storvsc driver

 arch/x86/hyperv/Makefile           |   2 +-
 arch/x86/hyperv/hv_init.c          |  70 +++++--
 arch/x86/hyperv/ivm.c              | 289 +++++++++++++++++++++++++++++
 arch/x86/include/asm/hyperv-tlfs.h |  22 +++
 arch/x86/include/asm/mshyperv.h    |  90 +++++++--
 arch/x86/kernel/cpu/mshyperv.c     |   5 +
 arch/x86/kernel/pci-swiotlb.c      |   3 +-
 drivers/hv/channel.c               |  44 ++++-
 drivers/hv/connection.c            |  68 ++++++-
 drivers/hv/hv.c                    |  73 ++++++--
 drivers/hv/hyperv_vmbus.h          |   3 +
 drivers/hv/ring_buffer.c           |  83 ++++++---
 drivers/hv/vmbus_drv.c             |   3 +
 drivers/iommu/hyperv-iommu.c       | 127 +++++++++++++
 drivers/net/hyperv/hyperv_net.h    |  11 ++
 drivers/net/hyperv/netvsc.c        | 137 +++++++++++++-
 drivers/net/hyperv/rndis_filter.c  |   3 +
 drivers/scsi/storvsc_drv.c         |  67 ++++++-
 drivers/uio/uio_hv_generic.c       |   5 +
 include/asm-generic/hyperv-tlfs.h  |   1 +
 include/asm-generic/mshyperv.h     |  18 +-
 include/linux/hyperv.h             |  12 +-
 include/linux/swiotlb.h            |   5 +
 kernel/dma/swiotlb.c               |  13 +-
 mm/ioremap.c                       |   1 +
 mm/vmalloc.c                       |   1 +
 26 files changed, 1068 insertions(+), 88 deletions(-)
 create mode 100644 arch/x86/hyperv/ivm.c

-- 
2.25.1

[RFC V2 PATCH 1/12] x86/HV: Initialize GHCB page in Isolation VM

[Tianyu Lan]

From: Tianyu Lan <Tianyu.Lan@microsoft.com>

Hyper-V exposes GHCB page via SEV ES GHCB MSR for SNP guest
to communicate with hypervisor. Map GHCB page for all
cpus to read/write MSR register and submit hvcall request
via GHCB.

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
 arch/x86/hyperv/hv_init.c      | 52 +++++++++++++++++++++++++++++++---
 include/asm-generic/mshyperv.h |  1 +
 2 files changed, 49 insertions(+), 4 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 0db5137d5b81..90e65fbf4c58 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -82,6 +82,9 @@ static int hv_cpu_init(unsigned int cpu)
 	struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()];
 	void **input_arg;
 	struct page *pg;
+	u64 ghcb_gpa;
+	void *ghcb_va;
+	void **ghcb_base;
 
 	/* hv_cpu_init() can be called with IRQs disabled from hv_resume() */
 	pg = alloc_pages(irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL, hv_root_partition ? 1 : 0);
@@ -128,6 +131,17 @@ static int hv_cpu_init(unsigned int cpu)
 		wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, val);
 	}
 
+	if (ms_hyperv.ghcb_base) {
+		rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa);
+
+		ghcb_va = ioremap_cache(ghcb_gpa, HV_HYP_PAGE_SIZE);
+		if (!ghcb_va)
+			return -ENOMEM;
+
+		ghcb_base = (void **)this_cpu_ptr(ms_hyperv.ghcb_base);
+		*ghcb_base = ghcb_va;
+	}
+
 	return 0;
 }
 
@@ -223,6 +237,7 @@ static int hv_cpu_die(unsigned int cpu)
 	unsigned long flags;
 	void **input_arg;
 	void *pg;
+	void **ghcb_va = NULL;
 
 	local_irq_save(flags);
 	input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
@@ -236,6 +251,13 @@ static int hv_cpu_die(unsigned int cpu)
 		*output_arg = NULL;
 	}
 
+	if (ms_hyperv.ghcb_base) {
+		ghcb_va = (void **)this_cpu_ptr(ms_hyperv.ghcb_base);
+		if (*ghcb_va)
+			iounmap(*ghcb_va);
+		*ghcb_va = NULL;
+	}
+
 	local_irq_restore(flags);
 
 	free_pages((unsigned long)pg, hv_root_partition ? 1 : 0);
@@ -372,6 +394,9 @@ void __init hyperv_init(void)
 	u64 guest_id, required_msrs;
 	union hv_x64_msr_hypercall_contents hypercall_msr;
 	int cpuhp, i;
+	u64 ghcb_gpa;
+	void *ghcb_va;
+	void **ghcb_base;
 
 	if (x86_hyper_type != X86_HYPER_MS_HYPERV)
 		return;
@@ -432,9 +457,24 @@ void __init hyperv_init(void)
 			VMALLOC_END, GFP_KERNEL, PAGE_KERNEL_ROX,
 			VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
 			__builtin_return_address(0));
-	if (hv_hypercall_pg == NULL) {
-		wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
-		goto remove_cpuhp_state;
+	if (hv_hypercall_pg == NULL)
+		goto clean_guest_os_id;
+
+	if (hv_isolation_type_snp()) {
+		ms_hyperv.ghcb_base = alloc_percpu(void *);
+		if (!ms_hyperv.ghcb_base)
+			goto clean_guest_os_id;
+
+		rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa);
+		ghcb_va = ioremap_cache(ghcb_gpa, HV_HYP_PAGE_SIZE);
+		if (!ghcb_va) {
+			free_percpu(ms_hyperv.ghcb_base);
+			ms_hyperv.ghcb_base = NULL;
+			goto clean_guest_os_id;
+		}
+
+		ghcb_base = (void **)this_cpu_ptr(ms_hyperv.ghcb_base);
+		*ghcb_base = ghcb_va;
 	}
 
 	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
@@ -499,7 +539,8 @@ void __init hyperv_init(void)
 
 	return;
 
-remove_cpuhp_state:
+clean_guest_os_id:
+	wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
 	cpuhp_remove_state(cpuhp);
 free_vp_assist_page:
 	kfree(hv_vp_assist_page);
@@ -528,6 +569,9 @@ void hyperv_cleanup(void)
 	 */
 	hv_hypercall_pg = NULL;
 
+	if (ms_hyperv.ghcb_base)
+		free_percpu(ms_hyperv.ghcb_base);
+
 	/* Reset the hypercall page */
 	hypercall_msr.as_uint64 = 0;
 	wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index dff58a3db5d5..c6f4c5c20fb8 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -35,6 +35,7 @@ struct ms_hyperv_info {
 	u32 max_lp_index;
 	u32 isolation_config_a;
 	u32 isolation_config_b;
+	void  __percpu **ghcb_base;
 };
 extern struct ms_hyperv_info ms_hyperv;
 
-- 
2.25.1

[RFC V2 PATCH 2/12] x86/HV: Initialize shared memory boundary in Isolation VM

[Tianyu Lan]

From: Tianyu Lan <Tianyu.Lan@microsoft.com>

Hyper-V exposes shared memory boundary via cpuid HYPERV_
CPUID_ISOLATION_CONFIG and store it in the shared_gpa_
boundary of ms_hyperv struct. This prepares to share
memory with host for AMD SEV SNP guest.

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
 arch/x86/kernel/cpu/mshyperv.c |  2 ++
 include/asm-generic/mshyperv.h | 13 ++++++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index e88bc296afca..aeafd4017c89 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -328,6 +328,8 @@ static void __init ms_hyperv_init_platform(void)
 	if (ms_hyperv.features_b & HV_ISOLATION) {
 		ms_hyperv.isolation_config_a = cpuid_eax(HYPERV_CPUID_ISOLATION_CONFIG);
 		ms_hyperv.isolation_config_b = cpuid_ebx(HYPERV_CPUID_ISOLATION_CONFIG);
+		ms_hyperv.shared_gpa_boundary =
+			(u64)1 << ms_hyperv.shared_gpa_boundary_bits;
 
 		pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B 0x%x\n",
 			ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b);
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index c6f4c5c20fb8..b73e201abc70 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -34,8 +34,19 @@ struct ms_hyperv_info {
 	u32 max_vp_index;
 	u32 max_lp_index;
 	u32 isolation_config_a;
-	u32 isolation_config_b;
+	union
+	{
+		u32 isolation_config_b;
+		struct {
+			u32 cvm_type : 4;
+			u32 Reserved11 : 1;
+			u32 shared_gpa_boundary_active : 1;
+			u32 shared_gpa_boundary_bits : 6;
+			u32 Reserved12 : 20;
+		};
+	};
 	void  __percpu **ghcb_base;
+	u64 shared_gpa_boundary;
 };
 extern struct ms_hyperv_info ms_hyperv;
 
-- 
2.25.1

[RFC V2 PATCH 3/12] x86/Hyper-V: Add new hvcall guest address host visibility support

[Tianyu Lan]

From: Tianyu Lan <Tianyu.Lan@microsoft.com>

Add new hvcall guest address host visibility support. Mark vmbus
ring buffer visible to host when create gpadl buffer and mark back
to not visible when tear down gpadl buffer.

Co-Developed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
 arch/x86/hyperv/Makefile           |  2 +-
 arch/x86/hyperv/ivm.c              | 90 ++++++++++++++++++++++++++++++
 arch/x86/include/asm/hyperv-tlfs.h | 22 ++++++++
 arch/x86/include/asm/mshyperv.h    |  2 +
 drivers/hv/channel.c               | 34 ++++++++++-
 include/asm-generic/hyperv-tlfs.h  |  1 +
 include/linux/hyperv.h             | 12 +++-
 7 files changed, 159 insertions(+), 4 deletions(-)
 create mode 100644 arch/x86/hyperv/ivm.c

diff --git a/arch/x86/hyperv/Makefile b/arch/x86/hyperv/Makefile
index 48e2c51464e8..5d2de10809ae 100644
--- a/arch/x86/hyperv/Makefile
+++ b/arch/x86/hyperv/Makefile
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
-obj-y			:= hv_init.o mmu.o nested.o irqdomain.o
+obj-y			:= hv_init.o mmu.o nested.o irqdomain.o ivm.o
 obj-$(CONFIG_X86_64)	+= hv_apic.o hv_proc.o
 
 ifdef CONFIG_X86_64
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
new file mode 100644
index 000000000000..a5950b7a9214
--- /dev/null
+++ b/arch/x86/hyperv/ivm.c
@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Hyper-V Isolation VM interface with paravisor and hypervisor
+ *
+ * Author:
+ *  Tianyu Lan <Tianyu.Lan@microsoft.com>
+ */
+
+#include <linux/hyperv.h>
+#include <linux/types.h>
+#include <linux/bitfield.h>
+#include <asm/io.h>
+#include <asm/mshyperv.h>
+
+/*
+ * hv_set_mem_host_visibility - Set host visibility for specified memory.
+ */
+int hv_set_mem_host_visibility(void *kbuffer, u32 size, u32 visibility)
+{
+	int i, pfn;
+	int pagecount = size >> HV_HYP_PAGE_SHIFT;
+	u64 *pfn_array;
+	int ret = 0;
+
+	pfn_array = vzalloc(HV_HYP_PAGE_SIZE);
+	if (!pfn_array)
+		return -ENOMEM;
+
+	for (i = 0, pfn = 0; i < pagecount; i++) {
+		pfn_array[pfn] = virt_to_hvpfn(kbuffer + i * HV_HYP_PAGE_SIZE);
+		pfn++;
+
+		if (pfn == HV_MAX_MODIFY_GPA_REP_COUNT || i == pagecount - 1) {
+			ret = hv_mark_gpa_visibility(pfn, pfn_array, visibility);
+			pfn = 0;
+
+			if (ret)
+				goto err_free_pfn_array;
+		}
+	}
+
+ err_free_pfn_array:
+	vfree(pfn_array);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(hv_set_mem_host_visibility);
+
+int hv_mark_gpa_visibility(u16 count, const u64 pfn[], u32 visibility)
+{
+	struct hv_input_modify_sparse_gpa_page_host_visibility **input_pcpu;
+	struct hv_input_modify_sparse_gpa_page_host_visibility *input;
+	u16 pages_processed;
+	u64 hv_status;
+	unsigned long flags;
+
+	/* no-op if partition isolation is not enabled */
+	if (!hv_is_isolation_supported())
+		return 0;
+
+	if (count > HV_MAX_MODIFY_GPA_REP_COUNT) {
+		pr_err("Hyper-V: GPA count:%d exceeds supported:%lu\n", count,
+			HV_MAX_MODIFY_GPA_REP_COUNT);
+		return -EINVAL;
+	}
+
+	local_irq_save(flags);
+	input_pcpu = (struct hv_input_modify_sparse_gpa_page_host_visibility **)
+			this_cpu_ptr(hyperv_pcpu_input_arg);
+	input = *input_pcpu;
+	if (unlikely(!input)) {
+		local_irq_restore(flags);
+		return -1;
+	}
+
+	input->partition_id = HV_PARTITION_ID_SELF;
+	input->host_visibility = visibility;
+	input->reserved0 = 0;
+	input->reserved1 = 0;
+	memcpy((void *)input->gpa_page_list, pfn, count * sizeof(*pfn));
+	hv_status = hv_do_rep_hypercall(
+			HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY, count,
+			0, input, &pages_processed);
+	local_irq_restore(flags);
+
+	if (!(hv_status & HV_HYPERCALL_RESULT_MASK))
+		return 0;
+
+	return hv_status & HV_HYPERCALL_RESULT_MASK;
+}
+EXPORT_SYMBOL(hv_mark_gpa_visibility);
diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index e6cd3fee562b..1f1ce9afb6f1 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -236,6 +236,15 @@ enum hv_isolation_type {
 /* TSC invariant control */
 #define HV_X64_MSR_TSC_INVARIANT_CONTROL	0x40000118
 
+/* Hyper-V GPA map flags */
+#define HV_MAP_GPA_PERMISSIONS_NONE            0x0
+#define HV_MAP_GPA_READABLE                    0x1
+#define HV_MAP_GPA_WRITABLE                    0x2
+
+#define VMBUS_PAGE_VISIBLE_READ_ONLY HV_MAP_GPA_READABLE
+#define VMBUS_PAGE_VISIBLE_READ_WRITE (HV_MAP_GPA_READABLE|HV_MAP_GPA_WRITABLE)
+#define VMBUS_PAGE_NOT_VISIBLE HV_MAP_GPA_PERMISSIONS_NONE
+
 /*
  * Declare the MSR used to setup pages used to communicate with the hypervisor.
  */
@@ -564,4 +573,17 @@ enum hv_interrupt_type {
 
 #include <asm-generic/hyperv-tlfs.h>
 
+/* All input parameters should be in single page. */
+#define HV_MAX_MODIFY_GPA_REP_COUNT		\
+	((PAGE_SIZE / sizeof(u64)) - 2)
+
+/* HvCallModifySparseGpaPageHostVisibility hypercall */
+struct hv_input_modify_sparse_gpa_page_host_visibility {
+	u64 partition_id;
+	u32 host_visibility:2;
+	u32 reserved0:30;
+	u32 reserved1;
+	u64 gpa_page_list[HV_MAX_MODIFY_GPA_REP_COUNT];
+} __packed;
+
 #endif
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index ccf60a809a17..d9437f096ce5 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -269,6 +269,8 @@ int hv_map_ioapic_interrupt(int ioapic_id, bool level, int vcpu, int vector,
 		struct hv_interrupt_entry *entry);
 int hv_unmap_ioapic_interrupt(int ioapic_id, struct hv_interrupt_entry *entry);
 
+int hv_set_mem_host_visibility(void *kbuffer, u32 size, u32 visibility);
+int hv_mark_gpa_visibility(u16 count, const u64 pfn[], u32 visibility);
 #else /* CONFIG_HYPERV */
 static inline void hyperv_init(void) {}
 static inline void hyperv_setup_mmu_ops(void) {}
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index 0bd202de7960..407b74d72f3f 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -400,7 +400,7 @@ static int __vmbus_establish_gpadl(struct vmbus_channel *channel,
 	struct list_head *curr;
 	u32 next_gpadl_handle;
 	unsigned long flags;
-	int ret = 0;
+	int ret = 0, index;
 
 	next_gpadl_handle =
 		(atomic_inc_return(&vmbus_connection.next_gpadl_handle) - 1);
@@ -409,6 +409,13 @@ static int __vmbus_establish_gpadl(struct vmbus_channel *channel,
 	if (ret)
 		return ret;
 
+	ret = hv_set_mem_host_visibility(kbuffer, size,
+					 VMBUS_PAGE_VISIBLE_READ_WRITE);
+	if (ret) {
+		pr_warn("Failed to set host visibility.\n");
+		return ret;
+	}
+
 	init_completion(&msginfo->waitevent);
 	msginfo->waiting_channel = channel;
 
@@ -484,6 +491,16 @@ static int __vmbus_establish_gpadl(struct vmbus_channel *channel,
 	}
 
 	kfree(msginfo);
+
+	if (type == HV_GPADL_BUFFER)
+		index = 0;
+	else
+		index = channel->gpadl_range[1].gpadlhandle ? 2 : 1;
+
+	channel->gpadl_range[index].size = size;
+	channel->gpadl_range[index].buffer = kbuffer;
+	channel->gpadl_range[index].gpadlhandle = *gpadl_handle;
+
 	return ret;
 }
 
@@ -743,7 +760,7 @@ int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
 	struct vmbus_channel_gpadl_teardown *msg;
 	struct vmbus_channel_msginfo *info;
 	unsigned long flags;
-	int ret;
+	int ret, i;
 
 	info = kzalloc(sizeof(*info) +
 		       sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
@@ -791,6 +808,19 @@ int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 
 	kfree(info);
+
+	/* Find gpadl buffer virtual address and size. */
+	for (i = 0; i < VMBUS_GPADL_RANGE_COUNT; i++)
+		if (channel->gpadl_range[i].gpadlhandle == gpadl_handle)
+			break;
+
+	if (hv_set_mem_host_visibility(channel->gpadl_range[i].buffer,
+				       channel->gpadl_range[i].size,
+				       VMBUS_PAGE_NOT_VISIBLE))
+		pr_warn("Fail to set mem host visibility.\n");
+
+	channel->gpadl_range[i].gpadlhandle = 0;
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h
index 83448e837ded..ad19f4199f90 100644
--- a/include/asm-generic/hyperv-tlfs.h
+++ b/include/asm-generic/hyperv-tlfs.h
@@ -158,6 +158,7 @@ struct ms_hyperv_tsc_page {
 #define HVCALL_RETARGET_INTERRUPT		0x007e
 #define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE 0x00af
 #define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_LIST 0x00b0
+#define HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY 0x00db
 
 #define HV_FLUSH_ALL_PROCESSORS			BIT(0)
 #define HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES	BIT(1)
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index f1d74dcf0353..b877a68f326c 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -788,6 +788,14 @@ struct vmbus_device {
 	bool allowed_in_isolated;
 };
 
+struct vmbus_gpadl_range {
+	u32 gpadlhandle;
+	u32 size;
+	void *buffer;
+};
+
+#define VMBUS_GPADL_RANGE_COUNT		3
+
 struct vmbus_channel {
 	struct list_head listentry;
 
@@ -808,6 +816,8 @@ struct vmbus_channel {
 	struct completion rescind_event;
 
 	u32 ringbuffer_gpadlhandle;
+	/* GPADL_RING and Send/Receive GPADL_BUFFER. */
+	struct vmbus_gpadl_range gpadl_range[VMBUS_GPADL_RANGE_COUNT];
 
 	/* Allocated memory for ring buffer */
 	struct page *ringbuffer_page;
@@ -1182,7 +1192,7 @@ extern int vmbus_establish_gpadl(struct vmbus_channel *channel,
 				      u32 *gpadl_handle);
 
 extern int vmbus_teardown_gpadl(struct vmbus_channel *channel,
-				     u32 gpadl_handle);
+				u32 gpadl_handle);
 
 void vmbus_reset_channel_cb(struct vmbus_channel *channel);
 
-- 
2.25.1

[RFC V2 PATCH 4/12] HV: Add Write/Read MSR registers via ghcb

[Tianyu Lan]

From: Tianyu Lan <Tianyu.Lan@microsoft.com>

Hyper-V provides GHCB protocol to write Synthetic Interrupt
Controller MSR registers and these registers are emulated by
Hypervisor rather than paravisor.

Hyper-V requests to write SINTx MSR registers twice(once via
GHCB and once via wrmsr instruction including the proxy bit 21)
Guest OS ID MSR also needs to be set via GHCB.

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
 arch/x86/hyperv/hv_init.c       |  18 +----
 arch/x86/hyperv/ivm.c           | 130 ++++++++++++++++++++++++++++++++
 arch/x86/include/asm/mshyperv.h |  87 +++++++++++++++++----
 arch/x86/kernel/cpu/mshyperv.c  |   3 +
 drivers/hv/hv.c                 |  65 +++++++++++-----
 include/asm-generic/mshyperv.h  |   4 +-
 6 files changed, 261 insertions(+), 46 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 90e65fbf4c58..87b1dd9c84d6 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -475,6 +475,9 @@ void __init hyperv_init(void)
 
 		ghcb_base = (void **)this_cpu_ptr(ms_hyperv.ghcb_base);
 		*ghcb_base = ghcb_va;
+
+		/* Hyper-V requires to write guest os id via ghcb in SNP IVM. */
+		hv_ghcb_msr_write(HV_X64_MSR_GUEST_OS_ID, guest_id);
 	}
 
 	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
@@ -561,6 +564,7 @@ void hyperv_cleanup(void)
 
 	/* Reset our OS id */
 	wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
+	hv_ghcb_msr_write(HV_X64_MSR_GUEST_OS_ID, 0);
 
 	/*
 	 * Reset hypercall page reference before reset the page,
@@ -668,17 +672,3 @@ bool hv_is_hibernation_supported(void)
 	return !hv_root_partition && acpi_sleep_state_supported(ACPI_STATE_S4);
 }
 EXPORT_SYMBOL_GPL(hv_is_hibernation_supported);
-
-enum hv_isolation_type hv_get_isolation_type(void)
-{
-	if (!(ms_hyperv.features_b & HV_ISOLATION))
-		return HV_ISOLATION_TYPE_NONE;
-	return FIELD_GET(HV_ISOLATION_TYPE, ms_hyperv.isolation_config_b);
-}
-EXPORT_SYMBOL_GPL(hv_get_isolation_type);
-
-bool hv_is_isolation_supported(void)
-{
-	return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE;
-}
-EXPORT_SYMBOL_GPL(hv_is_isolation_supported);
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index a5950b7a9214..2ec64b367aaf 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -6,12 +6,139 @@
  *  Tianyu Lan <Tianyu.Lan@microsoft.com>
  */
 
+#include <linux/types.h>
+#include <linux/bitfield.h>
 #include <linux/hyperv.h>
 #include <linux/types.h>
 #include <linux/bitfield.h>
 #include <asm/io.h>
+#include <asm/svm.h>
+#include <asm/sev-es.h>
 #include <asm/mshyperv.h>
 
+union hv_ghcb {
+	struct ghcb ghcb;
+} __packed __aligned(PAGE_SIZE);
+
+void hv_ghcb_msr_write(u64 msr, u64 value)
+{
+	union hv_ghcb *hv_ghcb;
+	void **ghcb_base;
+	unsigned long flags;
+
+	if (!ms_hyperv.ghcb_base)
+		return;
+
+	local_irq_save(flags);
+	ghcb_base = (void **)this_cpu_ptr(ms_hyperv.ghcb_base);
+	hv_ghcb = (union hv_ghcb *)*ghcb_base;
+	if (!hv_ghcb) {
+		local_irq_restore(flags);
+		return;
+	}
+
+	memset(hv_ghcb, 0x00, HV_HYP_PAGE_SIZE);
+
+	hv_ghcb->ghcb.protocol_version = 1;
+	hv_ghcb->ghcb.ghcb_usage = 0;
+
+	ghcb_set_sw_exit_code(&hv_ghcb->ghcb, SVM_EXIT_MSR);
+	ghcb_set_rcx(&hv_ghcb->ghcb, msr);
+	ghcb_set_rax(&hv_ghcb->ghcb, lower_32_bits(value));
+	ghcb_set_rdx(&hv_ghcb->ghcb, value >> 32);
+	ghcb_set_sw_exit_info_1(&hv_ghcb->ghcb, 1);
+	ghcb_set_sw_exit_info_2(&hv_ghcb->ghcb, 0);
+
+	VMGEXIT();
+
+	if ((hv_ghcb->ghcb.save.sw_exit_info_1 & 0xffffffff) == 1)
+		pr_warn("Fail to write msr via ghcb.\n.");
+
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(hv_ghcb_msr_write);
+
+void hv_ghcb_msr_read(u64 msr, u64 *value)
+{
+	union hv_ghcb *hv_ghcb;
+	void **ghcb_base;
+	unsigned long flags;
+
+	if (!ms_hyperv.ghcb_base)
+		return;
+
+	local_irq_save(flags);
+	ghcb_base = (void **)this_cpu_ptr(ms_hyperv.ghcb_base);
+	hv_ghcb = (union hv_ghcb *)*ghcb_base;
+	if (!hv_ghcb) {
+		local_irq_restore(flags);
+		return;
+	}
+
+	memset(hv_ghcb, 0x00, PAGE_SIZE);
+	hv_ghcb->ghcb.protocol_version = 1;
+	hv_ghcb->ghcb.ghcb_usage = 0;
+
+	ghcb_set_sw_exit_code(&hv_ghcb->ghcb, SVM_EXIT_MSR);
+	ghcb_set_rcx(&hv_ghcb->ghcb, msr);
+	ghcb_set_sw_exit_info_1(&hv_ghcb->ghcb, 0);
+	ghcb_set_sw_exit_info_2(&hv_ghcb->ghcb, 0);
+
+	VMGEXIT();
+
+	if ((hv_ghcb->ghcb.save.sw_exit_info_1 & 0xffffffff) == 1)
+		pr_warn("Fail to write msr via ghcb.\n.");
+	else
+		*value = (u64)lower_32_bits(hv_ghcb->ghcb.save.rax)
+			| ((u64)lower_32_bits(hv_ghcb->ghcb.save.rdx) << 32);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(hv_ghcb_msr_read);
+
+void hv_sint_rdmsrl_ghcb(u64 msr, u64 *value)
+{
+	hv_ghcb_msr_read(msr, value);
+}
+EXPORT_SYMBOL_GPL(hv_sint_rdmsrl_ghcb);
+
+void hv_sint_wrmsrl_ghcb(u64 msr, u64 value)
+{
+	hv_ghcb_msr_write(msr, value);
+
+	/* Write proxy bit vua wrmsrl instruction. */
+	if (msr >= HV_X64_MSR_SINT0 && msr <= HV_X64_MSR_SINT15)
+		wrmsrl(msr, value | 1 << 20);
+}
+EXPORT_SYMBOL_GPL(hv_sint_wrmsrl_ghcb);
+
+inline void hv_signal_eom_ghcb(void)
+{
+	hv_sint_wrmsrl_ghcb(HV_X64_MSR_EOM, 0);
+}
+EXPORT_SYMBOL_GPL(hv_signal_eom_ghcb);
+
+enum hv_isolation_type hv_get_isolation_type(void)
+{
+	if (!(ms_hyperv.features_b & HV_ISOLATION))
+		return HV_ISOLATION_TYPE_NONE;
+	return FIELD_GET(HV_ISOLATION_TYPE, ms_hyperv.isolation_config_b);
+}
+EXPORT_SYMBOL_GPL(hv_get_isolation_type);
+
+bool hv_is_isolation_supported(void)
+{
+	return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE;
+}
+EXPORT_SYMBOL_GPL(hv_is_isolation_supported);
+
+DEFINE_STATIC_KEY_FALSE(isolation_type_snp);
+
+bool hv_isolation_type_snp(void)
+{
+	return static_branch_unlikely(&isolation_type_snp);
+}
+EXPORT_SYMBOL_GPL(hv_isolation_type_snp);
+
 /*
  * hv_set_mem_host_visibility - Set host visibility for specified memory.
  */
@@ -22,6 +149,9 @@ int hv_set_mem_host_visibility(void *kbuffer, u32 size, u32 visibility)
 	u64 *pfn_array;
 	int ret = 0;
 
+	if (!hv_is_isolation_supported())
+		return 0;
+
 	pfn_array = vzalloc(HV_HYP_PAGE_SIZE);
 	if (!pfn_array)
 		return -ENOMEM;
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index d9437f096ce5..73501dbbc240 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -10,6 +10,8 @@
 #include <asm/nospec-branch.h>
 #include <asm/paravirt.h>
 
+DECLARE_STATIC_KEY_FALSE(isolation_type_snp);
+
 typedef int (*hyperv_fill_flush_list_func)(
 		struct hv_guest_mapping_flush_list *flush,
 		void *data);
@@ -19,24 +21,64 @@ typedef int (*hyperv_fill_flush_list_func)(
 #define hv_init_timer_config(timer, val) \
 	wrmsrl(HV_X64_MSR_STIMER0_CONFIG + (2*timer), val)
 
-#define hv_get_simp(val) rdmsrl(HV_X64_MSR_SIMP, val)
-#define hv_set_simp(val) wrmsrl(HV_X64_MSR_SIMP, val)
+#define hv_get_sint_reg(val, reg) {		\
+	if (hv_isolation_type_snp())		\
+		hv_get_##reg##_ghcb(&val);		\
+	else					\
+		rdmsrl(HV_X64_MSR_##reg, val);	\
+	}
+
+#define hv_set_sint_reg(val, reg) {		\
+	if (hv_isolation_type_snp())		\
+		hv_set_##reg##_ghcb(val);		\
+	else					\
+		wrmsrl(HV_X64_MSR_##reg, val);	\
+	}
+
 
-#define hv_get_siefp(val) rdmsrl(HV_X64_MSR_SIEFP, val)
-#define hv_set_siefp(val) wrmsrl(HV_X64_MSR_SIEFP, val)
+#define hv_get_simp(val) hv_get_sint_reg(val, SIMP)
+#define hv_get_siefp(val) hv_get_sint_reg(val, SIEFP)
 
-#define hv_get_synic_state(val) rdmsrl(HV_X64_MSR_SCONTROL, val)
-#define hv_set_synic_state(val) wrmsrl(HV_X64_MSR_SCONTROL, val)
+#define hv_set_simp(val) hv_set_sint_reg(val, SIMP)
+#define hv_set_siefp(val) hv_set_sint_reg(val, SIEFP)
+
+#define hv_get_synic_state(val) {			\
+	if (hv_isolation_type_snp())			\
+		hv_get_synic_state_ghcb(&val);		\
+	else						\
+		rdmsrl(HV_X64_MSR_SCONTROL, val);	\
+	}
+#define hv_set_synic_state(val) {			\
+	if (hv_isolation_type_snp())			\
+		hv_set_synic_state_ghcb(val);		\
+	else						\
+		wrmsrl(HV_X64_MSR_SCONTROL, val);	\
+	}
 
 #define hv_get_vp_index(index) rdmsrl(HV_X64_MSR_VP_INDEX, index)
 
-#define hv_signal_eom() wrmsrl(HV_X64_MSR_EOM, 0)
+#define hv_signal_eom() {			 \
+	if (hv_isolation_type_snp() &&		 \
+	    old_msg_type != HVMSG_TIMER_EXPIRED) \
+		hv_signal_eom_ghcb();		 \
+	else					 \
+		wrmsrl(HV_X64_MSR_EOM, 0);	 \
+	}
 
-#define hv_get_synint_state(int_num, val) \
-	rdmsrl(HV_X64_MSR_SINT0 + int_num, val)
-#define hv_set_synint_state(int_num, val) \
-	wrmsrl(HV_X64_MSR_SINT0 + int_num, val)
-#define hv_recommend_using_aeoi() \
+#define hv_get_synint_state(int_num, val) {		\
+	if (hv_isolation_type_snp())			\
+		hv_get_synint_state_ghcb(int_num, &val);\
+	else						\
+		rdmsrl(HV_X64_MSR_SINT0 + int_num, val);\
+	}
+#define hv_set_synint_state(int_num, val) {		\
+	if (hv_isolation_type_snp())			\
+		hv_set_synint_state_ghcb(int_num, val);	\
+	else						\
+		wrmsrl(HV_X64_MSR_SINT0 + int_num, val);\
+	}
+
+#define hv_recommend_using_aeoi()				\
 	(!(ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED))
 
 #define hv_get_crash_ctl(val) \
@@ -271,6 +313,25 @@ int hv_unmap_ioapic_interrupt(int ioapic_id, struct hv_interrupt_entry *entry);
 
 int hv_set_mem_host_visibility(void *kbuffer, u32 size, u32 visibility);
 int hv_mark_gpa_visibility(u16 count, const u64 pfn[], u32 visibility);
+void hv_sint_wrmsrl_ghcb(u64 msr, u64 value);
+void hv_sint_rdmsrl_ghcb(u64 msr, u64 *value);
+void hv_signal_eom_ghcb(void);
+void hv_ghcb_msr_write(u64 msr, u64 value);
+void hv_ghcb_msr_read(u64 msr, u64 *value);
+
+#define hv_get_synint_state_ghcb(int_num, val)			\
+	hv_sint_rdmsrl_ghcb(HV_X64_MSR_SINT0 + int_num, val)
+#define hv_set_synint_state_ghcb(int_num, val) \
+	hv_sint_wrmsrl_ghcb(HV_X64_MSR_SINT0 + int_num, val)
+
+#define hv_get_SIMP_ghcb(val) hv_sint_rdmsrl_ghcb(HV_X64_MSR_SIMP, val)
+#define hv_set_SIMP_ghcb(val) hv_sint_wrmsrl_ghcb(HV_X64_MSR_SIMP, val)
+
+#define hv_get_SIEFP_ghcb(val) hv_sint_rdmsrl_ghcb(HV_X64_MSR_SIEFP, val)
+#define hv_set_SIEFP_ghcb(val) hv_sint_wrmsrl_ghcb(HV_X64_MSR_SIEFP, val)
+
+#define hv_get_synic_state_ghcb(val) hv_sint_rdmsrl_ghcb(HV_X64_MSR_SCONTROL, val)
+#define hv_set_synic_state_ghcb(val) hv_sint_wrmsrl_ghcb(HV_X64_MSR_SCONTROL, val)
 #else /* CONFIG_HYPERV */
 static inline void hyperv_init(void) {}
 static inline void hyperv_setup_mmu_ops(void) {}
@@ -289,9 +350,9 @@ static inline int hyperv_flush_guest_mapping_range(u64 as,
 {
 	return -1;
 }
+static inline void hv_signal_eom_ghcb(void) { };
 #endif /* CONFIG_HYPERV */
 
-
 #include <asm-generic/mshyperv.h>
 
 #endif
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index aeafd4017c89..6eaa0891c0f7 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -333,6 +333,9 @@ static void __init ms_hyperv_init_platform(void)
 
 		pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B 0x%x\n",
 			ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b);
+
+		if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP)
+			static_branch_enable(&isolation_type_snp);
 	}
 
 	if (ms_hyperv.hints & HV_X64_ENLIGHTENED_VMCS_RECOMMENDED) {
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index f202ac7f4b3d..069530eeb7c6 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -99,17 +99,24 @@ int hv_synic_alloc(void)
 		tasklet_init(&hv_cpu->msg_dpc,
 			     vmbus_on_msg_dpc, (unsigned long) hv_cpu);
 
-		hv_cpu->synic_message_page =
-			(void *)get_zeroed_page(GFP_ATOMIC);
-		if (hv_cpu->synic_message_page == NULL) {
-			pr_err("Unable to allocate SYNIC message page\n");
-			goto err;
-		}
+		/*
+		 * Synic message and event pages are allocated by paravisor.
+		 * Skip these pages allocation here.
+		 */
+		if (!hv_isolation_type_snp()) {
+			hv_cpu->synic_message_page =
+				(void *)get_zeroed_page(GFP_ATOMIC);
+			if (hv_cpu->synic_message_page == NULL) {
+				pr_err("Unable to allocate SYNIC message page\n");
+				goto err;
+			}
 
-		hv_cpu->synic_event_page = (void *)get_zeroed_page(GFP_ATOMIC);
-		if (hv_cpu->synic_event_page == NULL) {
-			pr_err("Unable to allocate SYNIC event page\n");
-			goto err;
+			hv_cpu->synic_event_page =
+				(void *)get_zeroed_page(GFP_ATOMIC);
+			if (hv_cpu->synic_event_page == NULL) {
+				pr_err("Unable to allocate SYNIC event page\n");
+				goto err;
+			}
 		}
 
 		hv_cpu->post_msg_page = (void *)get_zeroed_page(GFP_ATOMIC);
@@ -136,10 +143,17 @@ void hv_synic_free(void)
 	for_each_present_cpu(cpu) {
 		struct hv_per_cpu_context *hv_cpu
 			= per_cpu_ptr(hv_context.cpu_context, cpu);
+		free_page((unsigned long)hv_cpu->post_msg_page);
+
+		/*
+		 * Synic message and event pages are allocated by paravisor.
+		 * Skip free these pages here.
+		 */
+		if (hv_isolation_type_snp())
+			continue;
 
 		free_page((unsigned long)hv_cpu->synic_event_page);
 		free_page((unsigned long)hv_cpu->synic_message_page);
-		free_page((unsigned long)hv_cpu->post_msg_page);
 	}
 
 	kfree(hv_context.hv_numa_map);
@@ -161,20 +175,36 @@ void hv_synic_enable_regs(unsigned int cpu)
 	union hv_synic_sint shared_sint;
 	union hv_synic_scontrol sctrl;
 
-	/* Setup the Synic's message page */
+
+	/* Setup the Synic's message. */
 	hv_get_simp(simp.as_uint64);
 	simp.simp_enabled = 1;
-	simp.base_simp_gpa = virt_to_phys(hv_cpu->synic_message_page)
-		>> HV_HYP_PAGE_SHIFT;
+
+	if (hv_isolation_type_snp()) {
+		hv_cpu->synic_message_page
+			= ioremap_cache(simp.base_simp_gpa << HV_HYP_PAGE_SHIFT,
+					HV_HYP_PAGE_SIZE);
+		if (!hv_cpu->synic_message_page)
+			pr_err("Fail to map syinc message page.\n");
+	} else {
+		simp.base_simp_gpa = virt_to_phys(hv_cpu->synic_message_page)
+			>> HV_HYP_PAGE_SHIFT;
+	}
 
 	hv_set_simp(simp.as_uint64);
 
 	/* Setup the Synic's event page */
 	hv_get_siefp(siefp.as_uint64);
 	siefp.siefp_enabled = 1;
-	siefp.base_siefp_gpa = virt_to_phys(hv_cpu->synic_event_page)
-		>> HV_HYP_PAGE_SHIFT;
-
+	if (hv_isolation_type_snp()) {
+		hv_cpu->synic_event_page = ioremap_cache(
+			 siefp.base_siefp_gpa << HV_HYP_PAGE_SHIFT, HV_HYP_PAGE_SIZE);
+		if (!hv_cpu->synic_event_page)
+			pr_err("Fail to map syinc event page.\n");
+	} else {
+		siefp.base_siefp_gpa = virt_to_phys(hv_cpu->synic_event_page)
+			>> HV_HYP_PAGE_SHIFT;
+	}
 	hv_set_siefp(siefp.as_uint64);
 
 	/* Setup the shared SINT. */
@@ -188,7 +218,6 @@ void hv_synic_enable_regs(unsigned int cpu)
 	/* Enable the global synic bit */
 	hv_get_synic_state(sctrl.as_uint64);
 	sctrl.enable = 1;
-
 	hv_set_synic_state(sctrl.as_uint64);
 }
 
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index b73e201abc70..59777377e641 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -23,6 +23,7 @@
 #include <linux/bitops.h>
 #include <linux/cpumask.h>
 #include <asm/ptrace.h>
+#include <asm/mshyperv.h>
 #include <asm/hyperv-tlfs.h>
 
 struct ms_hyperv_info {
@@ -52,7 +53,7 @@ extern struct ms_hyperv_info ms_hyperv;
 
 extern u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr);
 extern u64 hv_do_fast_hypercall8(u16 control, u64 input8);
-
+extern bool hv_isolation_type_snp(void);
 
 /* Generate the guest OS identifier as described in the Hyper-V TLFS */
 static inline  __u64 generate_guest_id(__u64 d_info1, __u64 kernel_version,
@@ -186,6 +187,7 @@ bool hv_is_hyperv_initialized(void);
 bool hv_is_hibernation_supported(void);
 enum hv_isolation_type hv_get_isolation_type(void);
 bool hv_is_isolation_supported(void);
+bool hv_isolation_type_snp(void);
 void hyperv_cleanup(void);
 #else /* CONFIG_HYPERV */
 static inline bool hv_is_hyperv_initialized(void) { return false; }
-- 
2.25.1