hyperv-tlfs.h defines Hyper-V interfaces from the Hyper-V Top Level Functional Spec (TLFS). The TLFS is distinctly oriented to x86/x64, and Hyper-V has not separated out the architecture-dependent parts into x86/x64 vs. ARM64. So hyperv-tlfs.h includes information for ARM64 that is not yet formally published. The TLFS is available here: docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/reference/tlfs mshyperv.h defines Linux-specific structures and routines for interacting with Hyper-V on ARM64. Signed-off-by: Michael Kelley <mikelley@xxxxxxxxxxxxx> Reviewed-by: James Morris <james.morris@xxxxxxxxxxxxx> --- MAINTAINERS | 2 + arch/arm64/include/asm/hyperv-tlfs.h | 353 +++++++++++++++++++++++++++++++++++ arch/arm64/include/asm/mshyperv.h | 291 +++++++++++++++++++++++++++++ 3 files changed, 646 insertions(+) create mode 100644 arch/arm64/include/asm/hyperv-tlfs.h create mode 100644 arch/arm64/include/asm/mshyperv.h diff --git a/MAINTAINERS b/MAINTAINERS index 9d5eeff..9c06145 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -6617,6 +6617,8 @@ F: arch/x86/include/asm/trace/hyperv.h F: arch/x86/include/asm/hyperv-tlfs.h F: arch/x86/kernel/cpu/mshyperv.c F: arch/x86/hyperv +F: arch/arm64/include/asm/hyperv-tlfs.h +F: arch/arm64/include/asm/mshyperv.h F: drivers/hid/hid-hyperv.c F: drivers/hv/ F: drivers/input/serio/hyperv-keyboard.c diff --git a/arch/arm64/include/asm/hyperv-tlfs.h b/arch/arm64/include/asm/hyperv-tlfs.h new file mode 100644 index 0000000..3f88306 --- /dev/null +++ b/arch/arm64/include/asm/hyperv-tlfs.h @@ -0,0 +1,353 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * This file contains definitions from the Hyper-V Hypervisor Top-Level + * Functional Specification (TLFS): + * https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/reference/tlfs + * + * Copyright (C) 2018, Microsoft, Inc. + * + * Author : Michael Kelley <mikelley@xxxxxxxxxxxxx> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published + * by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for more + * details. + */ + +#ifndef _ASM_ARM64_HYPERV_H +#define _ASM_ARM64_HYPERV_H + +#include <linux/types.h> + +/* + * These Hyper-V registers provide information equivalent to the CPUID + * instruction on x86/x64. + */ +#define HvRegisterHypervisorVersion 0x00000100 /*CPUID 0x40000002 */ +#define HvRegisterPrivilegesAndFeaturesInfo 0x00000200 /*CPUID 0x40000003 */ +#define HvRegisterFeaturesInfo 0x00000201 /*CPUID 0x40000004 */ +#define HvRegisterImplementationLimitsInfo 0x00000202 /*CPUID 0x40000005 */ +#define HvARM64RegisterInterfaceVersion 0x00090006 /*CPUID 0x40000001 */ + +/* + * Feature identification. HvRegisterPrivilegesAndFeaturesInfo returns a + * 128-bit value with flags indicating which features are available to the + * partition based upon the current partition privileges. The 128-bit + * value is broken up with different portions stored in different 32-bit + * fields in the ms_hyperv structure. + */ + +/* Partition Reference Counter available*/ +#define HV_MSR_TIME_REF_COUNT_AVAILABLE (1 << 1) + +/* + * Synthetic Timers available + */ +#define HV_MSR_SYNTIMER_AVAILABLE (1 << 3) + +/* Frequency MSRs available */ +#define HV_FEATURE_FREQUENCY_MSRS_AVAILABLE (1 << 8) + +/* Reference TSC available */ +#define HV_MSR_REFERENCE_TSC_AVAILABLE (1 << 9) + +/* Crash MSR available */ +#define HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE (1 << 10) + + +/* + * This group of flags is in the high order 64-bits of the returned + * 128-bit value. + */ + +/* STIMER direct mode is available */ +#define HV_STIMER_DIRECT_MODE_AVAILABLE (1 << 19) + +/* + * Implementation recommendations in register + * HvRegisterFeaturesInfo. Indicates which behaviors the hypervisor + * recommends the OS implement for optimal performance. + */ + +/* + * Recommend not using Auto EOI + */ +#define HV_DEPRECATING_AEOI_RECOMMENDED (1 << 9) + +/* + * Temporary #defines for compatibility with architecture + * independent Hyper-V drivers. Remove these once x86-isms + * have been removed from arch independent drivers. + */ +#define HV_X64_MSR_SYNTIMER_AVAILABLE \ + HV_MSR_SYNTIMER_AVAILABLE +#define HV_X64_STIMER_DIRECT_MODE_AVAILABLE \ + HV_STIMER_DIRECT_MODE_AVAILABLE +#define HV_X64_DEPRECATING_AEOI_RECOMMENDED \ + HV_DEPRECATING_AEOI_RECOMMENDED +#define HV_X64_MSR_STIMER0_COUNT 0 +#define HV_X64_MSR_STIMER0_CONFIG 0 +#define HV_X64_MSR_SINT0 0 + +/* + * Synthetic register definitions equivalent to MSRs on x86/x64 + */ +#define HvRegisterCrashP0 0x00000210 +#define HvRegisterCrashP1 0x00000211 +#define HvRegisterCrashP2 0x00000212 +#define HvRegisterCrashP3 0x00000213 +#define HvRegisterCrashP4 0x00000214 +#define HvRegisterCrashCtl 0x00000215 + +#define HvRegisterGuestOsId 0x00090002 +#define HvRegisterVpIndex 0x00090003 +#define HvRegisterTimeRefCount 0x00090004 +#define HvRegisterReferenceTsc 0x00090017 + +#define HvRegisterSint0 0x000A0000 +#define HvRegisterSint1 0x000A0001 +#define HvRegisterSint2 0x000A0002 +#define HvRegisterSint3 0x000A0003 +#define HvRegisterSint4 0x000A0004 +#define HvRegisterSint5 0x000A0005 +#define HvRegisterSint6 0x000A0006 +#define HvRegisterSint7 0x000A0007 +#define HvRegisterSint8 0x000A0008 +#define HvRegisterSint9 0x000A0009 +#define HvRegisterSint10 0x000A000A +#define HvRegisterSint11 0x000A000B +#define HvRegisterSint12 0x000A000C +#define HvRegisterSint13 0x000A000D +#define HvRegisterSint14 0x000A000E +#define HvRegisterSint15 0x000A000F +#define HvRegisterScontrol 0x000A0010 +#define HvRegisterSversion 0x000A0011 +#define HvRegisterSifp 0x000A0012 +#define HvRegisterSipp 0x000A0013 +#define HvRegisterEom 0x000A0014 +#define HvRegisterSirbp 0x000A0015 + +#define HvRegisterStimer0Config 0x000B0000 +#define HvRegisterStimer0Count 0x000B0001 +#define HvRegisterStimer1Config 0x000B0002 +#define HvRegisterStimer1Count 0x000B0003 +#define HvRegisterStimer2Config 0x000B0004 +#define HvRegisterStimer2Count 0x000B0005 +#define HvRegisterStimer3Config 0x000B0006 +#define HvRegisterStimer3Count 0x000B0007 + +/* + * Crash notification flag used in the + * CrashCtl register. + */ +#define HV_CRASH_CTL_CRASH_NOTIFY (1ULL << 63) + +/* + * The guest OS needs to register the guest ID with the hypervisor. + * The guest ID is a 64 bit entity and the structure of this ID is + * specified in the Hyper-V specification: + * + * msdn.microsoft.com/en-us/library/windows/hardware/ff542653%28v=vs.85%29.aspx + * + * While the current guideline does not specify how Linux guest ID(s) + * need to be generated, our plan is to publish the guidelines for + * Linux and other guest operating systems that currently are hosted + * on Hyper-V. The implementation here conforms to this yet + * unpublished guidelines. + * + * + * Bit(s) + * 63 - Indicates if the OS is Open Source or not; 1 is Open Source + * 62:56 - Os Type; Linux is 0x100 + * 55:48 - Distro specific identification + * 47:16 - Linux kernel version number + * 15:0 - Distro specific identification + * + * + */ +#define HV_LINUX_VENDOR_ID 0x8100 + +/* Declare the various hypercall operations. */ +#define HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE 0x0002 +#define HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST 0x0003 +#define HVCALL_NOTIFY_LONG_SPIN_WAIT 0x0008 +#define HVCALL_SEND_IPI 0x000b +#define HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX 0x0013 +#define HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX 0x0014 +#define HVCALL_SEND_IPI_EX 0x0015 +#define HVCALL_GET_VP_REGISTERS 0x0050 +#define HVCALL_SET_VP_REGISTERS 0x0051 +#define HVCALL_POST_MESSAGE 0x005c +#define HVCALL_SIGNAL_EVENT 0x005d +#define HVCALL_RETARGET_INTERRUPT 0x007e +#define HVCALL_START_VIRTUAL_PROCESSOR 0x0099 +#define HVCALL_GET_VP_INDEX_FROM_APICID 0x009a + +/* Declare standard hypercall field values. */ +#define HV_PARTITION_ID_SELF ((u64)-1) +#define HV_VP_INDEX_SELF ((u32)-2) + +#define HV_HYPERCALL_FAST_BIT BIT(16) +#define HV_HYPERCALL_REP_COUNT_1 BIT_ULL(32) +#define HV_HYPERCALL_RESULT_MASK GENMASK_ULL(15, 0) + +/* Define the hypercall status result */ + +union hv_hypercall_status { + u64 as_uint64; + struct { + u16 status; + u16 reserved; + u16 reps_completed; /* Low 12 bits */ + u16 reserved2; + }; +}; + +/* hypercall status code */ +#define HV_STATUS_SUCCESS 0 +#define HV_STATUS_INVALID_HYPERCALL_CODE 2 +#define HV_STATUS_INVALID_HYPERCALL_INPUT 3 +#define HV_STATUS_INVALID_ALIGNMENT 4 +#define HV_STATUS_INSUFFICIENT_MEMORY 11 +#define HV_STATUS_INVALID_CONNECTION_ID 18 +#define HV_STATUS_INSUFFICIENT_BUFFERS 19 + +/* Define output layout for Get VP Register hypercall */ +struct hv_get_vp_register_output { + u64 registervaluelow; + u64 registervaluehigh; +}; + +#define HV_FLUSH_ALL_PROCESSORS BIT(0) +#define HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES BIT(1) +#define HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY BIT(2) +#define HV_FLUSH_USE_EXTENDED_RANGE_FORMAT BIT(3) + +enum HV_GENERIC_SET_FORMAT { + HV_GENERIC_SET_SPARSE_4K, + HV_GENERIC_SET_ALL, +}; + +/* + * The Hyper-V TimeRefCount register and the TSC + * page provide a guest VM clock with 100ns tick rate + */ +#define HV_CLOCK_HZ (NSEC_PER_SEC/100) + +/* + * The fields in this structure are set by Hyper-V and read + * by the Linux guest. They should be accessed with READ_ONCE() + * so the compiler doesn't optimize in a way that will cause + * problems. + */ +struct ms_hyperv_tsc_page { + u32 tsc_sequence; + u32 reserved1; + u64 tsc_scale; + s64 tsc_offset; + u64 reserved2[509]; +}; + +/* Define the number of synthetic interrupt sources. */ +#define HV_SYNIC_SINT_COUNT (16) +/* Define the expected SynIC version. */ +#define HV_SYNIC_VERSION_1 (0x1) + +#define HV_SYNIC_CONTROL_ENABLE (1ULL << 0) +#define HV_SYNIC_SIMP_ENABLE (1ULL << 0) +#define HV_SYNIC_SIEFP_ENABLE (1ULL << 0) +#define HV_SYNIC_SINT_MASKED (1ULL << 16) +#define HV_SYNIC_SINT_AUTO_EOI (1ULL << 17) +#define HV_SYNIC_SINT_VECTOR_MASK (0xFF) + +#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 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, +}; + +/* 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 { + __u32 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; +}; + +/* Define the synthetic interrupt message page layout. */ +struct hv_message_page { + struct hv_message sint_message[HV_SYNIC_SINT_COUNT]; +}; + +/* Define timer message payload structure. */ +struct hv_timer_message_payload { + __u32 timer_index; + __u32 reserved; + __u64 expiration_time; /* When the timer expired */ + __u64 delivery_time; /* When the message was delivered */ +}; + +#define HV_STIMER_ENABLE (1ULL << 0) +#define HV_STIMER_PERIODIC (1ULL << 1) +#define HV_STIMER_LAZY (1ULL << 2) +#define HV_STIMER_AUTOENABLE (1ULL << 3) +#define HV_STIMER_SINT(config) (__u8)(((config) >> 16) & 0x0F) + +#endif diff --git a/arch/arm64/include/asm/mshyperv.h b/arch/arm64/include/asm/mshyperv.h new file mode 100644 index 0000000..1428d13 --- /dev/null +++ b/arch/arm64/include/asm/mshyperv.h @@ -0,0 +1,291 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * Linux-specific definitions for managing interactions with Microsoft's + * Hyper-V hypervisor. Definitions that are specified in the Hyper-V + * Top Level Functional Spec (TLFS) should not go in this file, but + * should instead go in hyperv-tlfs.h. + * + * Copyright (C) 2018, Microsoft, Inc. + * + * Author : Michael Kelley <mikelley@xxxxxxxxxxxxx> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published + * by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for more + * details. + */ + +#ifndef _ASM_ARM64_MSHYPERV_H +#define _ASM_ARM64_MSHYPERV_H + +#include <linux/types.h> +#include <linux/interrupt.h> +#include <linux/clocksource.h> +#include <linux/irq.h> +#include <linux/irqdesc.h> +#include <asm/hyperv-tlfs.h> + +/* + * Hyper-V always runs with a page size of 4096. These definitions + * are used when communicating with Hyper-V using guest physical + * pages and guest physical page addresses, since the guest page + * size may not be 4096 on ARM64. + */ +#define HV_HYP_PAGE_SIZE 4096 +#define HV_HYP_PAGE_SHIFT 12 +#define HV_HYP_PAGE_MASK (~(HV_HYP_PAGE_SIZE - 1)) + + +struct ms_hyperv_info { + u32 features; + u32 misc_features; + u32 hints; + u32 max_vp_index; + u32 max_lp_index; +}; +extern struct ms_hyperv_info ms_hyperv; + +/* + * Define the IRQ numbers/vectors used by Hyper-V VMbus interrupts + * and by STIMER0 Direct Mode interrupts. Hyper-V should be supplying + * these values through ACPI, but there are no other interrupting + * devices in a Hyper-V VM on ARM64, so it's OK to hard code for now. + * The "CALLBACK_VECTOR" terminology is a left-over from the x86/x64 + * world that is used in architecture independent Hyper-V code. + */ +#define HYPERVISOR_CALLBACK_VECTOR 16 +#define HV_STIMER0_IRQNR 17 + +extern u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr); +extern u64 hv_do_fast_hypercall8(u16 control, u64 input8); + +extern u64 hv_do_hvc(u64 control, ...); +extern u64 hv_do_hvc_fast_get(u64 control, u64 input1, u64 input2, u64 input3, + struct hv_get_vp_register_output *output); + +/* + * Declare calls to get and set Hyper-V VP register values on ARM64, which + * requires a hypercall. + */ +extern void hv_set_vpreg(u32 reg, u64 value); +extern u64 hv_get_vpreg(u32 reg); +extern void hv_get_vpreg_128(u32 reg, struct hv_get_vp_register_output *result); + +/* + * The guest OS needs to register the guest ID with the hypervisor. + * The guest ID is a 64 bit entity and the structure of this ID is + * specified in the Hyper-V specification: + * + * msdn.microsoft.com/en-us/library/windows/hardware/ff542653%28v=vs.85%29.aspx + * + * While the current guideline does not specify how Linux guest ID(s) + * need to be generated, our plan is to publish the guidelines for + * Linux and other guest operating systems that currently are hosted + * on Hyper-V. The implementation here conforms to this yet + * unpublished guidelines. + * + * + * Bit(s) + * 63 - Indicates if the OS is Open Source or not; 1 is Open Source + * 62:56 - Os Type; Linux is 0x100 + * 55:48 - Distro specific identification + * 47:16 - Linux kernel version number + * 15:0 - Distro specific identification + * + * Generate the guest ID based on the guideline described above. + */ + +static inline __u64 generate_guest_id(__u64 d_info1, __u64 kernel_version, + __u64 d_info2) +{ + __u64 guest_id = 0; + + guest_id = (((__u64)HV_LINUX_VENDOR_ID) << 48); + guest_id |= (d_info1 << 48); + guest_id |= (kernel_version << 16); + guest_id |= d_info2; + + return guest_id; +} + + +/* Free the message slot and signal end-of-message if required */ +static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type) +{ + /* + * On crash we're reading some other CPU's message page and we need + * to be careful: this other CPU may already had cleared the header + * and the host may already had delivered some other message there. + * In case we blindly write msg->header.message_type we're going + * to lose it. We can still lose a message of the same type but + * we count on the fact that there can only be one + * CHANNELMSG_UNLOAD_RESPONSE and we don't care about other messages + * on crash. + */ + if (cmpxchg(&msg->header.message_type, old_msg_type, + HVMSG_NONE) != old_msg_type) + return; + + /* + * Make sure the write to MessageType (ie set to + * HVMSG_NONE) happens before we read the + * MessagePending and EOMing. Otherwise, the EOMing + * will not deliver any more messages since there is + * no empty slot + */ + mb(); + + if (msg->header.message_flags.msg_pending) { + /* + * This will cause message queue rescan to + * possibly deliver another msg from the + * hypervisor + */ + hv_set_vpreg(HvRegisterEom, 0); + } +} + +/* + * Use the Hyper-V provided stimer0 as the timer that is made + * available to the architecture independent Hyper-V drivers. + */ +#define hv_init_timer(timer, tick) \ + hv_set_vpreg(HvRegisterStimer0Count + (2*timer), tick) +#define hv_init_timer_config(timer, val) \ + hv_set_vpreg(HvRegisterStimer0Config + (2*timer), val) +#define hv_get_current_tick(tick) \ + (tick = hv_get_vpreg(HvRegisterTimeRefCount)) + +#define hv_get_simp(val) (val = hv_get_vpreg(HvRegisterSipp)) +#define hv_set_simp(val) hv_set_vpreg(HvRegisterSipp, val) + +#define hv_get_siefp(val) (val = hv_get_vpreg(HvRegisterSifp)) +#define hv_set_siefp(val) hv_set_vpreg(HvRegisterSifp, val) + +#define hv_get_synic_state(val) (val = hv_get_vpreg(HvRegisterScontrol)) +#define hv_set_synic_state(val) hv_set_vpreg(HvRegisterScontrol, val) + +#define hv_get_vp_index(index) (index = hv_get_vpreg(HvRegisterVpIndex)) + +/* + * Hyper-V SINT registers are numbered sequentially, so we can just + * add the SINT number to the register number of SINT0 + */ +#define hv_get_synint_state(sint_num, val) \ + (val = hv_get_vpreg(HvRegisterSint0 + sint_num)) +#define hv_set_synint_state(sint_num, val) \ + hv_set_vpreg(HvRegisterSint0 + sint_num, val) + +void hv_setup_vmbus_irq(void (*handler)(void)); +void hv_remove_vmbus_irq(void); +void hv_enable_vmbus_irq(void); +void hv_disable_vmbus_irq(void); + +void hv_setup_kexec_handler(void (*handler)(void)); +void hv_remove_kexec_handler(void); +void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs)); +void hv_remove_crash_handler(void); + +#if IS_ENABLED(CONFIG_HYPERV) +extern struct clocksource *hyperv_cs; + +/* + * Hypervisor's notion of virtual processor ID is different from + * Linux' notion of CPU ID. This information can only be retrieved + * in the context of the calling CPU. Setup a map for easy access + * to this information. + */ +extern u32 *hv_vp_index; +extern u32 hv_max_vp_index; + +/** + * hv_cpu_number_to_vp_number() - Map CPU to VP. + * @cpu_number: CPU number in Linux terms + * + * This function returns the mapping between the Linux processor + * number and the hypervisor's virtual processor number, useful + * in making hypercalls and such that talk about specific + * processors. + * + * Return: Virtual processor number in Hyper-V terms + */ +static inline int hv_cpu_number_to_vp_number(int cpu_number) +{ + return hv_vp_index[cpu_number]; +} + +void hyperv_report_panic(struct pt_regs *regs, long err); +bool hv_is_hyperv_initialized(void); +void hyperv_cleanup(void); +#else /* CONFIG_HYPERV */ +static inline bool hv_is_hyperv_initialized(void) { return false; } +static inline void hyperv_cleanup(void) {} +#endif /* CONFIG_HYPERV */ + +#if IS_ENABLED(CONFIG_HYPERV) +#define hv_enable_stimer0_percpu_irq(irq) enable_percpu_irq(irq, 0) +#define hv_disable_stimer0_percpu_irq(irq) disable_percpu_irq(irq) +extern int hv_setup_stimer0_irq(int *irq, int *vector, void (*handler)(void)); +extern void hv_remove_stimer0_irq(int irq); +#endif + +extern struct ms_hyperv_tsc_page *hv_get_tsc_page(void); +static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, + u64 *cur_tsc) +{ + u64 scale, offset; + u32 sequence; + + /* + * The protocol for reading Hyper-V TSC page is specified in Hypervisor + * Top-Level Functional Specification. To get the reference time we + * must do the following: + * - READ ReferenceTscSequence + * A special '0' value indicates the time source is unreliable and we + * need to use something else. + * - ReferenceTime = + * ((CNTVCT_EL0) * ReferenceTscScale) >> 64) + ReferenceTscOffset + * - READ ReferenceTscSequence again. In case its value has changed + * since our first reading we need to discard ReferenceTime and repeat + * the whole sequence as the hypervisor was updating the page in + * between. + */ + do { + sequence = READ_ONCE(tsc_pg->tsc_sequence); + /* + * Make sure we read sequence before we read other values from + * TSC page. + */ + smp_rmb(); + + scale = READ_ONCE(tsc_pg->tsc_scale); + offset = READ_ONCE(tsc_pg->tsc_offset); + isb(); + *cur_tsc = read_sysreg(cntvct_el0); + isb(); + + /* + * Make sure we read sequence after we read all other values + * from TSC page. + */ + smp_rmb(); + + } while (READ_ONCE(tsc_pg->tsc_sequence) != sequence); + + return mul_u64_u64_shr(*cur_tsc, scale, 64) + offset; +} + +static inline u64 hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg) +{ + u64 cur_tsc; + + return hv_read_tsc_page_tsc(tsc_pg, &cur_tsc); +} + +#endif -- 1.8.3.1 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
