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![Jinank Jain](/assets/img/avatar_default.png)
Detect if Linux is running as a nested hypervisor in the root partition for Microsoft Hypervisor, using flags provided by MSHV. Expose a new variable hv_nested that is used later for decisions specific to the nested use case. Signed-off-by: Jinank Jain <jinankjain@linux.microsoft.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/8e3e7112806e81d2292a66a56fe547162754ecea.1672639707.git.jinankjain@linux.microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
285 lines
8.3 KiB
C
285 lines
8.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Linux-specific definitions for managing interactions with Microsoft's
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* Hyper-V hypervisor. The definitions in this file are architecture
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* independent. See arch/<arch>/include/asm/mshyperv.h for definitions
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* that are specific to architecture <arch>.
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*
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* Definitions that are specified in the Hyper-V Top Level Functional
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* Spec (TLFS) should not go in this file, but should instead go in
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* hyperv-tlfs.h.
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*
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* Copyright (C) 2019, Microsoft, Inc.
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*
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* Author : Michael Kelley <mikelley@microsoft.com>
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*/
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#ifndef _ASM_GENERIC_MSHYPERV_H
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#define _ASM_GENERIC_MSHYPERV_H
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#include <linux/types.h>
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#include <linux/atomic.h>
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#include <linux/bitops.h>
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#include <linux/cpumask.h>
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#include <linux/nmi.h>
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#include <asm/ptrace.h>
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#include <asm/hyperv-tlfs.h>
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struct ms_hyperv_info {
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u32 features;
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u32 priv_high;
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u32 misc_features;
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u32 hints;
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u32 nested_features;
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u32 max_vp_index;
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u32 max_lp_index;
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u32 isolation_config_a;
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union {
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u32 isolation_config_b;
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struct {
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u32 cvm_type : 4;
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u32 reserved1 : 1;
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u32 shared_gpa_boundary_active : 1;
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u32 shared_gpa_boundary_bits : 6;
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u32 reserved2 : 20;
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};
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};
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u64 shared_gpa_boundary;
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};
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extern struct ms_hyperv_info ms_hyperv;
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extern bool hv_nested;
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extern void * __percpu *hyperv_pcpu_input_arg;
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extern void * __percpu *hyperv_pcpu_output_arg;
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extern u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr);
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extern u64 hv_do_fast_hypercall8(u16 control, u64 input8);
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extern bool hv_isolation_type_snp(void);
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/* Helper functions that provide a consistent pattern for checking Hyper-V hypercall status. */
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static inline int hv_result(u64 status)
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{
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return status & HV_HYPERCALL_RESULT_MASK;
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}
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static inline bool hv_result_success(u64 status)
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{
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return hv_result(status) == HV_STATUS_SUCCESS;
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}
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static inline unsigned int hv_repcomp(u64 status)
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{
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/* Bits [43:32] of status have 'Reps completed' data. */
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return (status & HV_HYPERCALL_REP_COMP_MASK) >>
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HV_HYPERCALL_REP_COMP_OFFSET;
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}
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/*
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* Rep hypercalls. Callers of this functions are supposed to ensure that
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* rep_count and varhead_size comply with Hyper-V hypercall definition.
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*/
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static inline u64 hv_do_rep_hypercall(u16 code, u16 rep_count, u16 varhead_size,
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void *input, void *output)
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{
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u64 control = code;
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u64 status;
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u16 rep_comp;
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control |= (u64)varhead_size << HV_HYPERCALL_VARHEAD_OFFSET;
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control |= (u64)rep_count << HV_HYPERCALL_REP_COMP_OFFSET;
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do {
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status = hv_do_hypercall(control, input, output);
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if (!hv_result_success(status))
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return status;
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rep_comp = hv_repcomp(status);
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control &= ~HV_HYPERCALL_REP_START_MASK;
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control |= (u64)rep_comp << HV_HYPERCALL_REP_START_OFFSET;
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touch_nmi_watchdog();
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} while (rep_comp < rep_count);
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return status;
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}
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/* Generate the guest OS identifier as described in the Hyper-V TLFS */
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static inline u64 hv_generate_guest_id(u64 kernel_version)
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{
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u64 guest_id;
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guest_id = (((u64)HV_LINUX_VENDOR_ID) << 48);
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guest_id |= (kernel_version << 16);
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return guest_id;
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}
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/* Free the message slot and signal end-of-message if required */
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static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type)
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{
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/*
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* On crash we're reading some other CPU's message page and we need
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* to be careful: this other CPU may already had cleared the header
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* and the host may already had delivered some other message there.
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* In case we blindly write msg->header.message_type we're going
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* to lose it. We can still lose a message of the same type but
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* we count on the fact that there can only be one
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* CHANNELMSG_UNLOAD_RESPONSE and we don't care about other messages
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* on crash.
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*/
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if (cmpxchg(&msg->header.message_type, old_msg_type,
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HVMSG_NONE) != old_msg_type)
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return;
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/*
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* The cmxchg() above does an implicit memory barrier to
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* ensure the write to MessageType (ie set to
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* HVMSG_NONE) happens before we read the
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* MessagePending and EOMing. Otherwise, the EOMing
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* will not deliver any more messages since there is
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* no empty slot
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*/
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if (msg->header.message_flags.msg_pending) {
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/*
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* This will cause message queue rescan to
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* possibly deliver another msg from the
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* hypervisor
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*/
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hv_set_register(HV_REGISTER_EOM, 0);
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}
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}
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void hv_setup_vmbus_handler(void (*handler)(void));
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void hv_remove_vmbus_handler(void);
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void hv_setup_stimer0_handler(void (*handler)(void));
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void hv_remove_stimer0_handler(void);
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void hv_setup_kexec_handler(void (*handler)(void));
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void hv_remove_kexec_handler(void);
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void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs));
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void hv_remove_crash_handler(void);
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extern int vmbus_interrupt;
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extern int vmbus_irq;
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extern bool hv_root_partition;
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#if IS_ENABLED(CONFIG_HYPERV)
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/*
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* Hypervisor's notion of virtual processor ID is different from
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* Linux' notion of CPU ID. This information can only be retrieved
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* in the context of the calling CPU. Setup a map for easy access
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* to this information.
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*/
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extern u32 *hv_vp_index;
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extern u32 hv_max_vp_index;
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extern u64 (*hv_read_reference_counter)(void);
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/* Sentinel value for an uninitialized entry in hv_vp_index array */
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#define VP_INVAL U32_MAX
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int __init hv_common_init(void);
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void __init hv_common_free(void);
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int hv_common_cpu_init(unsigned int cpu);
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int hv_common_cpu_die(unsigned int cpu);
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void *hv_alloc_hyperv_page(void);
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void *hv_alloc_hyperv_zeroed_page(void);
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void hv_free_hyperv_page(unsigned long addr);
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/**
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* hv_cpu_number_to_vp_number() - Map CPU to VP.
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* @cpu_number: CPU number in Linux terms
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*
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* This function returns the mapping between the Linux processor
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* number and the hypervisor's virtual processor number, useful
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* in making hypercalls and such that talk about specific
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* processors.
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*
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* Return: Virtual processor number in Hyper-V terms
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*/
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static inline int hv_cpu_number_to_vp_number(int cpu_number)
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{
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return hv_vp_index[cpu_number];
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}
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static inline int __cpumask_to_vpset(struct hv_vpset *vpset,
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const struct cpumask *cpus,
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bool exclude_self)
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{
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int cpu, vcpu, vcpu_bank, vcpu_offset, nr_bank = 1;
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int this_cpu = smp_processor_id();
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int max_vcpu_bank = hv_max_vp_index / HV_VCPUS_PER_SPARSE_BANK;
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/* vpset.valid_bank_mask can represent up to HV_MAX_SPARSE_VCPU_BANKS banks */
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if (max_vcpu_bank >= HV_MAX_SPARSE_VCPU_BANKS)
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return 0;
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/*
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* Clear all banks up to the maximum possible bank as hv_tlb_flush_ex
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* structs are not cleared between calls, we risk flushing unneeded
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* vCPUs otherwise.
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*/
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for (vcpu_bank = 0; vcpu_bank <= max_vcpu_bank; vcpu_bank++)
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vpset->bank_contents[vcpu_bank] = 0;
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/*
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* Some banks may end up being empty but this is acceptable.
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*/
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for_each_cpu(cpu, cpus) {
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if (exclude_self && cpu == this_cpu)
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continue;
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vcpu = hv_cpu_number_to_vp_number(cpu);
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if (vcpu == VP_INVAL)
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return -1;
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vcpu_bank = vcpu / HV_VCPUS_PER_SPARSE_BANK;
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vcpu_offset = vcpu % HV_VCPUS_PER_SPARSE_BANK;
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__set_bit(vcpu_offset, (unsigned long *)
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&vpset->bank_contents[vcpu_bank]);
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if (vcpu_bank >= nr_bank)
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nr_bank = vcpu_bank + 1;
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}
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vpset->valid_bank_mask = GENMASK_ULL(nr_bank - 1, 0);
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return nr_bank;
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}
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static inline int cpumask_to_vpset(struct hv_vpset *vpset,
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const struct cpumask *cpus)
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{
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return __cpumask_to_vpset(vpset, cpus, false);
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}
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static inline int cpumask_to_vpset_noself(struct hv_vpset *vpset,
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const struct cpumask *cpus)
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{
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WARN_ON_ONCE(preemptible());
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return __cpumask_to_vpset(vpset, cpus, true);
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}
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void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die);
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bool hv_is_hyperv_initialized(void);
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bool hv_is_hibernation_supported(void);
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enum hv_isolation_type hv_get_isolation_type(void);
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bool hv_is_isolation_supported(void);
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bool hv_isolation_type_snp(void);
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u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size);
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void hyperv_cleanup(void);
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bool hv_query_ext_cap(u64 cap_query);
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void hv_setup_dma_ops(struct device *dev, bool coherent);
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void *hv_map_memory(void *addr, unsigned long size);
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void hv_unmap_memory(void *addr);
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#else /* CONFIG_HYPERV */
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static inline bool hv_is_hyperv_initialized(void) { return false; }
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static inline bool hv_is_hibernation_supported(void) { return false; }
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static inline void hyperv_cleanup(void) {}
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static inline bool hv_is_isolation_supported(void) { return false; }
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static inline enum hv_isolation_type hv_get_isolation_type(void)
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{
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return HV_ISOLATION_TYPE_NONE;
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}
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#endif /* CONFIG_HYPERV */
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#endif
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