[RFC PATCH 11/18] virt/mshv: set up synic pages for intercept messages

[Nuno Das Neves <nunodasneves@linux.microsoft.com>]

Same idea as synic setup in drivers/hv/hv.c:hv_synic_enable_regs()
and hv_synic_disable_regs().
Setting up synic registers in both vmbus driver and mshv would clobber
them, but the vmbus driver will not run in the root partition, so this
is safe.

Co-developed-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
Signed-off-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
---
 arch/x86/include/asm/hyperv-tlfs.h      |  29 ---
 arch/x86/include/uapi/asm/hyperv-tlfs.h | 264 ++++++++++++++++++++++++
 include/asm-generic/hyperv-tlfs.h       |  46 +----
 include/linux/mshv.h                    |   1 +
 include/uapi/asm-generic/hyperv-tlfs.h  |  43 ++++
 virt/mshv/mshv_main.c                   |  98 ++++++++-
 6 files changed, 404 insertions(+), 77 deletions(-)

diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index 4cd44ae9bffb..c34a6bb4f457 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -267,35 +267,6 @@ struct hv_tsc_emulation_status {
 #define HV_X64_MSR_TSC_REFERENCE_ENABLE		0x00000001
 #define HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT	12
 
-
-/* Define hypervisor message types. */
-enum hv_message_type {
-	HVMSG_NONE			= 0x00000000,
-
-	/* Memory access messages. */
-	HVMSG_UNMAPPED_GPA		= 0x80000000,
-	HVMSG_GPA_INTERCEPT		= 0x80000001,
-
-	/* Timer notification messages. */
-	HVMSG_TIMER_EXPIRED		= 0x80000010,
-
-	/* Error messages. */
-	HVMSG_INVALID_VP_REGISTER_VALUE	= 0x80000020,
-	HVMSG_UNRECOVERABLE_EXCEPTION	= 0x80000021,
-	HVMSG_UNSUPPORTED_FEATURE	= 0x80000022,
-
-	/* Trace buffer complete messages. */
-	HVMSG_EVENTLOG_BUFFERCOMPLETE	= 0x80000040,
-
-	/* Platform-specific processor intercept messages. */
-	HVMSG_X64_IOPORT_INTERCEPT	= 0x80010000,
-	HVMSG_X64_MSR_INTERCEPT		= 0x80010001,
-	HVMSG_X64_CPUID_INTERCEPT	= 0x80010002,
-	HVMSG_X64_EXCEPTION_INTERCEPT	= 0x80010003,
-	HVMSG_X64_APIC_EOI		= 0x80010004,
-	HVMSG_X64_LEGACY_FP_ERROR	= 0x80010005
-};
-
 struct hv_nested_enlightenments_control {
 	struct {
 		__u32 directhypercall:1;
diff --git a/arch/x86/include/uapi/asm/hyperv-tlfs.h b/arch/x86/include/uapi/asm/hyperv-tlfs.h
index 2ff655962738..c6a27053f791 100644
--- a/arch/x86/include/uapi/asm/hyperv-tlfs.h
+++ b/arch/x86/include/uapi/asm/hyperv-tlfs.h
@@ -722,4 +722,268 @@ union hv_register_value {
 		pending_virtualization_fault_event;
 };
 
+/* Define hypervisor message types. */
+enum hv_message_type {
+	HVMSG_NONE				= 0x00000000,
+
+	/* Memory access messages. */
+	HVMSG_UNMAPPED_GPA			= 0x80000000,
+	HVMSG_GPA_INTERCEPT			= 0x80000001,
+
+	/* Timer notification messages. */
+	HVMSG_TIMER_EXPIRED			= 0x80000010,
+
+	/* Error messages. */
+	HVMSG_INVALID_VP_REGISTER_VALUE		= 0x80000020,
+	HVMSG_UNRECOVERABLE_EXCEPTION		= 0x80000021,
+	HVMSG_UNSUPPORTED_FEATURE		= 0x80000022,
+
+	/* Trace buffer complete messages. */
+	HVMSG_EVENTLOG_BUFFERCOMPLETE		= 0x80000040,
+
+	/* Platform-specific processor intercept messages. */
+	HVMSG_X64_IO_PORT_INTERCEPT		= 0x80010000,
+	HVMSG_X64_MSR_INTERCEPT			= 0x80010001,
+	HVMSG_X64_CPUID_INTERCEPT		= 0x80010002,
+	HVMSG_X64_EXCEPTION_INTERCEPT		= 0x80010003,
+	HVMSG_X64_APIC_EOI			= 0x80010004,
+	HVMSG_X64_LEGACY_FP_ERROR		= 0x80010005,
+	HVMSG_X64_IOMMU_PRQ			= 0x80010006,
+	HVMSG_X64_HALT				= 0x80010007,
+	HVMSG_X64_INTERRUPTION_DELIVERABLE	= 0x80010008,
+	HVMSG_X64_SIPI_INTERCEPT		= 0x80010009,
+};
+
+
+union hv_x64_vp_execution_state {
+	__u16 as_uint16;
+	struct {
+		__u16 cpl:2;
+		__u16 cr0_pe:1;
+		__u16 cr0_am:1;
+		__u16 efer_lma:1;
+		__u16 debug_active:1;
+		__u16 interruption_pending:1;
+		__u16 vtl:4;
+		__u16 enclave_mode:1;
+		__u16 interrupt_shadow:1;
+		__u16 virtualization_fault_active:1;
+		__u16 reserved:2;
+	};
+};
+
+/* Values for intercept_access_type field */
+#define HV_INTERCEPT_ACCESS_READ	0
+#define HV_INTERCEPT_ACCESS_WRITE	1
+#define HV_INTERCEPT_ACCESS_EXECUTE	2
+
+struct hv_x64_intercept_message_header {
+	__u32 vp_index;
+	__u8 instruction_length:4;
+	__u8 cr8:4; // only set for exo partitions
+	__u8 intercept_access_type;
+	union hv_x64_vp_execution_state execution_state;
+	struct hv_x64_segment_register cs_segment;
+	__u64 rip;
+	__u64 rflags;
+};
+
+#define HV_HYPERCALL_INTERCEPT_MAX_XMM_REGISTERS 6
+
+struct hv_x64_hypercall_intercept_message {
+	struct hv_x64_intercept_message_header header;
+	__u64 rax;
+	__u64 rbx;
+	__u64 rcx;
+	__u64 rdx;
+	__u64 r8;
+	__u64 rsi;
+	__u64 rdi;
+	struct hv_u128 xmmregisters[HV_HYPERCALL_INTERCEPT_MAX_XMM_REGISTERS];
+	struct {
+		__u32 isolated:1;
+		__u32 reserved:31;
+	};
+};
+
+union hv_x64_register_access_info {
+	union hv_register_value source_value;
+	enum hv_register_name destination_register;
+	__u64 source_address;
+	__u64 destination_address;
+};
+
+struct hv_x64_register_intercept_message {
+	struct hv_x64_intercept_message_header header;
+	struct {
+		__u8 is_memory_op:1;
+		__u8 reserved:7;
+	};
+	__u8 reserved8;
+	__u16 reserved16;
+	enum hv_register_name register_name;
+	union hv_x64_register_access_info access_info;
+};
+
+union hv_x64_memory_access_info {
+	__u8 as_uint8;
+	struct {
+		__u8 gva_valid:1;
+		__u8 gva_gpa_valid:1;
+		__u8 hypercall_output_pending:1;
+		__u8 tlb_locked_no_overlay:1;
+		__u8 reserved:4;
+	};
+};
+
+union hv_x64_io_port_access_info {
+	__u8 as_uint8;
+	struct {
+		__u8 access_size:3;
+		__u8 string_op:1;
+		__u8 rep_prefix:1;
+		__u8 reserved:3;
+	};
+};
+
+union hv_x64_exception_info {
+	__u8 as_uint8;
+	struct {
+		__u8 error_code_valid:1;
+		__u8 software_exception:1;
+		__u8 reserved:6;
+	};
+};
+
+enum hv_cache_type {
+	HV_CACHE_TYPE_UNCACHED	   = 0,
+	HV_CACHE_TYPE_WRITE_COMBINING = 1,
+	HV_CACHE_TYPE_WRITE_THROUGH   = 4,
+	HV_CACHE_TYPE_WRITE_PROTECTED = 5,
+	HV_CACHE_TYPE_WRITE_BACK	  = 6
+};
+
+struct hv_x64_memory_intercept_message {
+	struct hv_x64_intercept_message_header header;
+	enum hv_cache_type cache_type;
+	__u8 instruction_byte_count;
+	union hv_x64_memory_access_info memory_access_info;
+	__u8 tpr_priority;
+	__u8 reserved1;
+	__u64 guest_virtual_address;
+	__u64 guest_physical_address;
+	__u8 instruction_bytes[16];
+};
+
+struct hv_x64_cpuid_intercept_message {
+	struct hv_x64_intercept_message_header header;
+	__u64 rax;
+	__u64 rcx;
+	__u64 rdx;
+	__u64 rbx;
+	__u64 default_result_rax;
+	__u64 default_result_rcx;
+	__u64 default_result_rdx;
+	__u64 default_result_rbx;
+};
+
+struct hv_x64_msr_intercept_message {
+	struct hv_x64_intercept_message_header header;
+	__u32 msr_number;
+	__u32 reserved;
+	__u64 rdx;
+	__u64 rax;
+};
+
+struct hv_x64_io_port_intercept_message {
+	struct hv_x64_intercept_message_header header;
+	__u16 port_number;
+	union hv_x64_io_port_access_info access_info;
+	__u8 instruction_byte_count;
+	__u32 reserved;
+	__u64 rax;
+	__u8 instruction_bytes[16];
+	struct hv_x64_segment_register ds_segment;
+	struct hv_x64_segment_register es_segment;
+	__u64 rcx;
+	__u64 rsi;
+	__u64 rdi;
+};
+
+struct hv_x64_exception_intercept_message {
+	struct hv_x64_intercept_message_header header;
+	__u16 exception_vector;
+	union hv_x64_exception_info exception_info;
+	__u8 instruction_byte_count;
+	__u32 error_code;
+	__u64 exception_parameter;
+	__u64 reserved;
+	__u8 instruction_bytes[16];
+	struct hv_x64_segment_register ds_segment;
+	struct hv_x64_segment_register ss_segment;
+	__u64 rax;
+	__u64 rcx;
+	__u64 rdx;
+	__u64 rbx;
+	__u64 rsp;
+	__u64 rbp;
+	__u64 rsi;
+	__u64 rdi;
+	__u64 r8;
+	__u64 r9;
+	__u64 r10;
+	__u64 r11;
+	__u64 r12;
+	__u64 r13;
+	__u64 r14;
+	__u64 r15;
+};
+
+struct hv_x64_invalid_vp_register_message {
+	__u32 vp_index;
+	__u32 reserved;
+};
+
+struct hv_x64_unrecoverable_exception_message {
+	struct hv_x64_intercept_message_header header;
+};
+
+enum hv_x64_unsupported_feature_code {
+	hv_unsupported_feature_intercept = 1,
+	hv_unsupported_feature_task_switch_tss = 2
+};
+
+struct hv_x64_unsupported_feature_message {
+	__u32 vp_index;
+	enum hv_x64_unsupported_feature_code feature_code;
+	__u64 feature_parameter;
+};
+
+struct hv_x64_halt_message {
+	struct hv_x64_intercept_message_header header;
+};
+
+enum hv_x64_pending_interruption_type {
+	HV_X64_PENDING_INTERRUPT	= 0,
+	HV_X64_PENDING_NMI		= 2,
+	HV_X64_PENDING_EXCEPTION	= 3
+};
+
+struct hv_x64_interruption_deliverable_message {
+	struct hv_x64_intercept_message_header header;
+	enum hv_x64_pending_interruption_type deliverable_type;
+	__u32 rsvd;
+};
+
+struct hv_x64_sipi_intercept_message {
+	struct hv_x64_intercept_message_header header;
+	__u32 target_vp_index;
+	__u32 interrupt_vector;
+};
+
+struct hv_x64_apic_eoi_message {
+	__u32 vp_index;
+	__u32 interrupt_vector;
+};
+
 #endif
diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h
index b9295400c20b..e0185c3872a9 100644
--- a/include/asm-generic/hyperv-tlfs.h
+++ b/include/asm-generic/hyperv-tlfs.h
@@ -241,6 +241,8 @@ static inline const char *hv_status_to_string(enum hv_status status)
 /* Valid SynIC vectors are 16-255. */
 #define HV_SYNIC_FIRST_VALID_VECTOR	(16)
 
+#define HV_SYNIC_INTERCEPTION_SINT_INDEX 0x00000000
+
 #define HV_SYNIC_CONTROL_ENABLE		(1ULL << 0)
 #define HV_SYNIC_SIMP_ENABLE		(1ULL << 0)
 #define HV_SYNIC_SIEFP_ENABLE		(1ULL << 0)
@@ -250,49 +252,6 @@ static inline const char *hv_status_to_string(enum hv_status status)
 
 #define HV_SYNIC_STIMER_COUNT		(4)
 
-/* Define synthetic interrupt controller message constants. */
-#define HV_MESSAGE_SIZE			(256)
-#define HV_MESSAGE_PAYLOAD_BYTE_COUNT	(240)
-#define HV_MESSAGE_PAYLOAD_QWORD_COUNT	(30)
-
-/* Define synthetic interrupt controller message flags. */
-union hv_message_flags {
-	__u8 asu8;
-	struct {
-		__u8 msg_pending:1;
-		__u8 reserved:7;
-	} __packed;
-};
-
-/* Define port identifier type. */
-union hv_port_id {
-	__u32 asu32;
-	struct {
-		__u32 id:24;
-		__u32 reserved:8;
-	} __packed u;
-};
-
-/* Define synthetic interrupt controller message header. */
-struct hv_message_header {
-	__u32 message_type;
-	__u8 payload_size;
-	union hv_message_flags message_flags;
-	__u8 reserved[2];
-	union {
-		__u64 sender;
-		union hv_port_id port;
-	};
-} __packed;
-
-/* Define synthetic interrupt controller message format. */
-struct hv_message {
-	struct hv_message_header header;
-	union {
-		__u64 payload[HV_MESSAGE_PAYLOAD_QWORD_COUNT];
-	} u;
-} __packed;
-
 /* Define the synthetic interrupt message page layout. */
 struct hv_message_page {
 	struct hv_message sint_message[HV_SYNIC_SINT_COUNT];
@@ -306,7 +265,6 @@ struct hv_timer_message_payload {
 	__u64 delivery_time;	/* When the message was delivered */
 } __packed;
 
-
 /* Define synthetic interrupt controller flag constants. */
 #define HV_EVENT_FLAGS_COUNT		(256 * 8)
 #define HV_EVENT_FLAGS_LONG_COUNT	(256 / sizeof(unsigned long))
diff --git a/include/linux/mshv.h b/include/linux/mshv.h
index dfe469f573f9..7709aaa1e064 100644
--- a/include/linux/mshv.h
+++ b/include/linux/mshv.h
@@ -42,6 +42,7 @@ struct mshv_partition {
 };
 
 struct mshv {
+	struct hv_message_page __percpu **synic_message_page;
 	struct {
 		spinlock_t lock;
 		u64 count;
diff --git a/include/uapi/asm-generic/hyperv-tlfs.h b/include/uapi/asm-generic/hyperv-tlfs.h
index e7b09b9f00de..e87389054b68 100644
--- a/include/uapi/asm-generic/hyperv-tlfs.h
+++ b/include/uapi/asm-generic/hyperv-tlfs.h
@@ -6,6 +6,49 @@
 #define BIT(X)	(1ULL << (X))
 #endif
 
+/* Define synthetic interrupt controller message constants. */
+#define HV_MESSAGE_SIZE			(256)
+#define HV_MESSAGE_PAYLOAD_BYTE_COUNT	(240)
+#define HV_MESSAGE_PAYLOAD_QWORD_COUNT	(30)
+
+/* Define synthetic interrupt controller message flags. */
+union hv_message_flags {
+	__u8 asu8;
+	struct {
+		__u8 msg_pending:1;
+		__u8 reserved:7;
+	};
+};
+
+/* Define port identifier type. */
+union hv_port_id {
+	__u32 asu32;
+	struct {
+		__u32 id:24;
+		__u32 reserved:8;
+	} u;
+};
+
+/* Define synthetic interrupt controller message header. */
+struct hv_message_header {
+	enum hv_message_type message_type;
+	__u8 payload_size;
+	union hv_message_flags message_flags;
+	__u8 reserved[2];
+	union {
+		__u64 sender;
+		union hv_port_id port;
+	};
+};
+
+/* Define synthetic interrupt controller message format. */
+struct hv_message {
+	struct hv_message_header header;
+	union {
+		__u64 payload[HV_MESSAGE_PAYLOAD_QWORD_COUNT];
+	} u;
+};
+
 /* Userspace-visible partition creation flags */
 #define HV_PARTITION_CREATION_FLAG_SMT_ENABLED_GUEST                BIT(0)
 #define HV_PARTITION_CREATION_FLAG_GPA_LARGE_PAGES_DISABLED         BIT(3)
diff --git a/virt/mshv/mshv_main.c b/virt/mshv/mshv_main.c
index 2a10137a1e84..c9445d2edb37 100644
--- a/virt/mshv/mshv_main.c
+++ b/virt/mshv/mshv_main.c
@@ -15,6 +15,8 @@
 #include <linux/file.h>
 #include <linux/anon_inodes.h>
 #include <linux/mm.h>
+#include <linux/io.h>
+#include <linux/cpuhotplug.h>
 #include <linux/mshv.h>
 #include <asm/mshyperv.h>
 
@@ -1152,23 +1154,111 @@ mshv_dev_release(struct inode *inode, struct file *filp)
 	return 0;
 }
 
+static int
+mshv_synic_init(unsigned int cpu)
+{
+	union hv_synic_simp simp;
+	union hv_synic_sint sint;
+	union hv_synic_scontrol sctrl;
+	struct hv_message_page **msg_page =
+			this_cpu_ptr(mshv.synic_message_page);
+
+	/* Setup the Synic's message page */
+	hv_get_simp(simp.as_uint64);
+	simp.simp_enabled = true;
+	*msg_page = memremap(simp.base_simp_gpa << PAGE_SHIFT,
+			     PAGE_SIZE, MEMREMAP_WB);
+	if (!msg_page) {
+		pr_err("%s: memremap failed\n", __func__);
+		return -EFAULT;
+	}
+	hv_set_simp(simp.as_uint64);
+
+	/* Enable intercepts */
+	sint.as_uint64 = 0;
+	sint.vector = HYPERVISOR_CALLBACK_VECTOR;
+	sint.masked = false;
+	sint.auto_eoi = hv_recommend_using_aeoi();
+	hv_set_synint_state(HV_SYNIC_INTERCEPTION_SINT_INDEX, sint.as_uint64);
+
+	/* Enable global synic bit */
+	hv_get_synic_state(sctrl.as_uint64);
+	sctrl.enable = 1;
+	hv_set_synic_state(sctrl.as_uint64);
+
+	return 0;
+}
+
+static int
+mshv_synic_cleanup(unsigned int cpu)
+{
+	union hv_synic_sint sint;
+	union hv_synic_simp simp;
+	union hv_synic_scontrol sctrl;
+	struct hv_message_page **msg_page =
+			this_cpu_ptr(mshv.synic_message_page);
+
+	/* Disable the interrupt */
+	hv_get_synint_state(HV_SYNIC_INTERCEPTION_SINT_INDEX, sint.as_uint64);
+	sint.masked = true;
+	hv_set_synint_state(HV_SYNIC_INTERCEPTION_SINT_INDEX, sint.as_uint64);
+
+	/* Disable Synic's message page */
+	hv_get_simp(simp.as_uint64);
+	simp.simp_enabled = false;
+	hv_set_simp(simp.as_uint64);
+	memunmap(*msg_page);
+
+	/* Disable global synic bit */
+	hv_get_synic_state(sctrl.as_uint64);
+	sctrl.enable = 0;
+	hv_set_synic_state(sctrl.as_uint64);
+
+	return 0;
+}
+
+static int mshv_cpuhp_online;
+
 static int
 __init mshv_init(void)
 {
-	int r;
+	int ret;
 
-	r = misc_register(&mshv_dev);
-	if (r)
+	ret = misc_register(&mshv_dev);
+	if (ret) {
 		pr_err("%s: misc device register failed\n", __func__);
+		return ret;
+	}
+	spin_lock_init(&mshv.partitions.lock);
 
+	mshv.synic_message_page = alloc_percpu(struct hv_message_page *);
+	if (!mshv.synic_message_page) {
+		pr_err("%s: failed to allocate percpu synic page\n", __func__);
+		misc_deregister(&mshv_dev);
+		return -ENOMEM;
+	}
+
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "mshv_synic",
+				mshv_synic_init,
+				mshv_synic_cleanup);
+	if (ret < 0) {
+		pr_err("%s: failed to setup cpu hotplug state: %i\n",
+		       __func__, ret);
+		return ret;
+	}
+
+	mshv_cpuhp_online = ret;
 	spin_lock_init(&mshv.partitions.lock);
 
-	return r;
+	return 0;
 }
 
 static void
 __exit mshv_exit(void)
 {
+	cpuhp_remove_state(mshv_cpuhp_online);
+	free_percpu(mshv.synic_message_page);
+
 	misc_deregister(&mshv_dev);
 }
 
-- 
2.25.1