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![Tianyu Lan](/assets/img/avatar_default.png)
Hyper-V Isolation VM current code uses sev_es_ghcb_hv_call()
to read/write MSR via GHCB page and depends on the sev code.
This may cause regression when sev code changes interface
design.
The latest SEV-ES code requires to negotiate GHCB version before
reading/writing MSR via GHCB page and sev_es_ghcb_hv_call() doesn't
work for Hyper-V Isolation VM. Add Hyper-V ghcb related implementation
to decouple SEV and Hyper-V code. Negotiate GHCB version in the
hyperv_init() and use the version to communicate with Hyper-V
in the ghcb hv call function.
Fixes: 2ea29c5abb
("x86/sev: Save the negotiated GHCB version")
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20220614014553.1915929-1-ltykernel@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
615 lines
16 KiB
C
615 lines
16 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* X86 specific Hyper-V initialization code.
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*
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* Copyright (C) 2016, Microsoft, Inc.
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*
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* Author : K. Y. Srinivasan <kys@microsoft.com>
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*/
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#include <linux/efi.h>
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#include <linux/types.h>
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#include <linux/bitfield.h>
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#include <linux/io.h>
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#include <asm/apic.h>
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#include <asm/desc.h>
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#include <asm/sev.h>
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#include <asm/hypervisor.h>
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#include <asm/hyperv-tlfs.h>
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#include <asm/mshyperv.h>
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#include <asm/idtentry.h>
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#include <linux/kexec.h>
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#include <linux/version.h>
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#include <linux/vmalloc.h>
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#include <linux/mm.h>
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#include <linux/hyperv.h>
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#include <linux/slab.h>
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#include <linux/kernel.h>
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#include <linux/cpuhotplug.h>
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#include <linux/syscore_ops.h>
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#include <clocksource/hyperv_timer.h>
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#include <linux/highmem.h>
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#include <linux/swiotlb.h>
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int hyperv_init_cpuhp;
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u64 hv_current_partition_id = ~0ull;
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EXPORT_SYMBOL_GPL(hv_current_partition_id);
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void *hv_hypercall_pg;
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EXPORT_SYMBOL_GPL(hv_hypercall_pg);
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union hv_ghcb * __percpu *hv_ghcb_pg;
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/* Storage to save the hypercall page temporarily for hibernation */
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static void *hv_hypercall_pg_saved;
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struct hv_vp_assist_page **hv_vp_assist_page;
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EXPORT_SYMBOL_GPL(hv_vp_assist_page);
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static int hyperv_init_ghcb(void)
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{
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u64 ghcb_gpa;
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void *ghcb_va;
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void **ghcb_base;
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if (!hv_isolation_type_snp())
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return 0;
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if (!hv_ghcb_pg)
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return -EINVAL;
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/*
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* GHCB page is allocated by paravisor. The address
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* returned by MSR_AMD64_SEV_ES_GHCB is above shared
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* memory boundary and map it here.
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*/
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rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa);
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ghcb_va = memremap(ghcb_gpa, HV_HYP_PAGE_SIZE, MEMREMAP_WB);
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if (!ghcb_va)
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return -ENOMEM;
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ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);
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*ghcb_base = ghcb_va;
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return 0;
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}
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static int hv_cpu_init(unsigned int cpu)
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{
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union hv_vp_assist_msr_contents msr = { 0 };
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struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()];
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int ret;
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ret = hv_common_cpu_init(cpu);
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if (ret)
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return ret;
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if (!hv_vp_assist_page)
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return 0;
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if (!*hvp) {
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if (hv_root_partition) {
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/*
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* For root partition we get the hypervisor provided VP assist
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* page, instead of allocating a new page.
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*/
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rdmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
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*hvp = memremap(msr.pfn <<
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HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT,
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PAGE_SIZE, MEMREMAP_WB);
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} else {
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/*
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* The VP assist page is an "overlay" page (see Hyper-V TLFS's
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* Section 5.2.1 "GPA Overlay Pages"). Here it must be zeroed
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* out to make sure we always write the EOI MSR in
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* hv_apic_eoi_write() *after* the EOI optimization is disabled
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* in hv_cpu_die(), otherwise a CPU may not be stopped in the
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* case of CPU offlining and the VM will hang.
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*/
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*hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL | __GFP_ZERO);
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if (*hvp)
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msr.pfn = vmalloc_to_pfn(*hvp);
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}
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WARN_ON(!(*hvp));
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if (*hvp) {
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msr.enable = 1;
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wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
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}
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}
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return hyperv_init_ghcb();
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}
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static void (*hv_reenlightenment_cb)(void);
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static void hv_reenlightenment_notify(struct work_struct *dummy)
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{
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struct hv_tsc_emulation_status emu_status;
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rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
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/* Don't issue the callback if TSC accesses are not emulated */
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if (hv_reenlightenment_cb && emu_status.inprogress)
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hv_reenlightenment_cb();
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}
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static DECLARE_DELAYED_WORK(hv_reenlightenment_work, hv_reenlightenment_notify);
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void hyperv_stop_tsc_emulation(void)
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{
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u64 freq;
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struct hv_tsc_emulation_status emu_status;
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rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
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emu_status.inprogress = 0;
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wrmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
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rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
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tsc_khz = div64_u64(freq, 1000);
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}
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EXPORT_SYMBOL_GPL(hyperv_stop_tsc_emulation);
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static inline bool hv_reenlightenment_available(void)
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{
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/*
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* Check for required features and privileges to make TSC frequency
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* change notifications work.
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*/
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return ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
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ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE &&
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ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT;
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}
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DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_reenlightenment)
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{
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ack_APIC_irq();
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inc_irq_stat(irq_hv_reenlightenment_count);
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schedule_delayed_work(&hv_reenlightenment_work, HZ/10);
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}
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void set_hv_tscchange_cb(void (*cb)(void))
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{
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struct hv_reenlightenment_control re_ctrl = {
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.vector = HYPERV_REENLIGHTENMENT_VECTOR,
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.enabled = 1,
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};
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struct hv_tsc_emulation_control emu_ctrl = {.enabled = 1};
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if (!hv_reenlightenment_available()) {
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pr_warn("Hyper-V: reenlightenment support is unavailable\n");
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return;
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}
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if (!hv_vp_index)
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return;
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hv_reenlightenment_cb = cb;
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/* Make sure callback is registered before we write to MSRs */
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wmb();
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re_ctrl.target_vp = hv_vp_index[get_cpu()];
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wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
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wrmsrl(HV_X64_MSR_TSC_EMULATION_CONTROL, *((u64 *)&emu_ctrl));
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put_cpu();
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}
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EXPORT_SYMBOL_GPL(set_hv_tscchange_cb);
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void clear_hv_tscchange_cb(void)
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{
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struct hv_reenlightenment_control re_ctrl;
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if (!hv_reenlightenment_available())
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return;
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rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
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re_ctrl.enabled = 0;
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wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
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hv_reenlightenment_cb = NULL;
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}
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EXPORT_SYMBOL_GPL(clear_hv_tscchange_cb);
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static int hv_cpu_die(unsigned int cpu)
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{
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struct hv_reenlightenment_control re_ctrl;
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unsigned int new_cpu;
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void **ghcb_va;
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if (hv_ghcb_pg) {
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ghcb_va = (void **)this_cpu_ptr(hv_ghcb_pg);
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if (*ghcb_va)
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memunmap(*ghcb_va);
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*ghcb_va = NULL;
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}
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hv_common_cpu_die(cpu);
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if (hv_vp_assist_page && hv_vp_assist_page[cpu]) {
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union hv_vp_assist_msr_contents msr = { 0 };
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if (hv_root_partition) {
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/*
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* For root partition the VP assist page is mapped to
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* hypervisor provided page, and thus we unmap the
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* page here and nullify it, so that in future we have
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* correct page address mapped in hv_cpu_init.
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*/
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memunmap(hv_vp_assist_page[cpu]);
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hv_vp_assist_page[cpu] = NULL;
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rdmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
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msr.enable = 0;
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}
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wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
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}
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if (hv_reenlightenment_cb == NULL)
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return 0;
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rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
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if (re_ctrl.target_vp == hv_vp_index[cpu]) {
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/*
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* Reassign reenlightenment notifications to some other online
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* CPU or just disable the feature if there are no online CPUs
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* left (happens on hibernation).
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*/
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new_cpu = cpumask_any_but(cpu_online_mask, cpu);
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if (new_cpu < nr_cpu_ids)
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re_ctrl.target_vp = hv_vp_index[new_cpu];
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else
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re_ctrl.enabled = 0;
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wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
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}
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return 0;
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}
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static int __init hv_pci_init(void)
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{
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int gen2vm = efi_enabled(EFI_BOOT);
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/*
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* For Generation-2 VM, we exit from pci_arch_init() by returning 0.
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* The purpose is to suppress the harmless warning:
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* "PCI: Fatal: No config space access function found"
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*/
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if (gen2vm)
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return 0;
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/* For Generation-1 VM, we'll proceed in pci_arch_init(). */
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return 1;
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}
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static int hv_suspend(void)
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{
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union hv_x64_msr_hypercall_contents hypercall_msr;
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int ret;
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if (hv_root_partition)
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return -EPERM;
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/*
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* Reset the hypercall page as it is going to be invalidated
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* across hibernation. Setting hv_hypercall_pg to NULL ensures
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* that any subsequent hypercall operation fails safely instead of
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* crashing due to an access of an invalid page. The hypercall page
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* pointer is restored on resume.
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*/
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hv_hypercall_pg_saved = hv_hypercall_pg;
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hv_hypercall_pg = NULL;
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/* Disable the hypercall page in the hypervisor */
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rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
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hypercall_msr.enable = 0;
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wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
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ret = hv_cpu_die(0);
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return ret;
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}
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static void hv_resume(void)
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{
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union hv_x64_msr_hypercall_contents hypercall_msr;
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int ret;
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ret = hv_cpu_init(0);
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WARN_ON(ret);
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/* Re-enable the hypercall page */
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rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
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hypercall_msr.enable = 1;
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hypercall_msr.guest_physical_address =
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vmalloc_to_pfn(hv_hypercall_pg_saved);
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wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
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hv_hypercall_pg = hv_hypercall_pg_saved;
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hv_hypercall_pg_saved = NULL;
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/*
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* Reenlightenment notifications are disabled by hv_cpu_die(0),
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* reenable them here if hv_reenlightenment_cb was previously set.
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*/
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if (hv_reenlightenment_cb)
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set_hv_tscchange_cb(hv_reenlightenment_cb);
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}
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/* Note: when the ops are called, only CPU0 is online and IRQs are disabled. */
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static struct syscore_ops hv_syscore_ops = {
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.suspend = hv_suspend,
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.resume = hv_resume,
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};
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static void (* __initdata old_setup_percpu_clockev)(void);
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static void __init hv_stimer_setup_percpu_clockev(void)
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{
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/*
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* Ignore any errors in setting up stimer clockevents
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* as we can run with the LAPIC timer as a fallback.
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*/
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(void)hv_stimer_alloc(false);
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/*
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* Still register the LAPIC timer, because the direct-mode STIMER is
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* not supported by old versions of Hyper-V. This also allows users
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* to switch to LAPIC timer via /sys, if they want to.
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*/
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if (old_setup_percpu_clockev)
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old_setup_percpu_clockev();
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}
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static void __init hv_get_partition_id(void)
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{
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struct hv_get_partition_id *output_page;
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u64 status;
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unsigned long flags;
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local_irq_save(flags);
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output_page = *this_cpu_ptr(hyperv_pcpu_output_arg);
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status = hv_do_hypercall(HVCALL_GET_PARTITION_ID, NULL, output_page);
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if (!hv_result_success(status)) {
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/* No point in proceeding if this failed */
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pr_err("Failed to get partition ID: %lld\n", status);
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BUG();
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}
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hv_current_partition_id = output_page->partition_id;
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local_irq_restore(flags);
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}
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/*
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* This function is to be invoked early in the boot sequence after the
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* hypervisor has been detected.
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*
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* 1. Setup the hypercall page.
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* 2. Register Hyper-V specific clocksource.
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* 3. Setup Hyper-V specific APIC entry points.
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*/
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void __init hyperv_init(void)
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{
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u64 guest_id;
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union hv_x64_msr_hypercall_contents hypercall_msr;
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int cpuhp;
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if (x86_hyper_type != X86_HYPER_MS_HYPERV)
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return;
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if (hv_common_init())
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return;
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hv_vp_assist_page = kcalloc(num_possible_cpus(),
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sizeof(*hv_vp_assist_page), GFP_KERNEL);
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if (!hv_vp_assist_page) {
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ms_hyperv.hints &= ~HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
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goto common_free;
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}
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if (hv_isolation_type_snp()) {
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/* Negotiate GHCB Version. */
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if (!hv_ghcb_negotiate_protocol())
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hv_ghcb_terminate(SEV_TERM_SET_GEN,
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GHCB_SEV_ES_PROT_UNSUPPORTED);
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hv_ghcb_pg = alloc_percpu(union hv_ghcb *);
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if (!hv_ghcb_pg)
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goto free_vp_assist_page;
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}
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cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
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hv_cpu_init, hv_cpu_die);
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if (cpuhp < 0)
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goto free_ghcb_page;
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/*
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* Setup the hypercall page and enable hypercalls.
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* 1. Register the guest ID
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* 2. Enable the hypercall and register the hypercall page
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*/
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guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);
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wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
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/* Hyper-V requires to write guest os id via ghcb in SNP IVM. */
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hv_ghcb_msr_write(HV_X64_MSR_GUEST_OS_ID, guest_id);
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hv_hypercall_pg = __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START,
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VMALLOC_END, GFP_KERNEL, PAGE_KERNEL_ROX,
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VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
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__builtin_return_address(0));
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if (hv_hypercall_pg == NULL)
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goto clean_guest_os_id;
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rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
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hypercall_msr.enable = 1;
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if (hv_root_partition) {
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struct page *pg;
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void *src, *dst;
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/*
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* For the root partition, the hypervisor will set up its
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* hypercall page. The hypervisor guarantees it will not show
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* up in the root's address space. The root can't change the
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* location of the hypercall page.
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*
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* Order is important here. We must enable the hypercall page
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* so it is populated with code, then copy the code to an
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* executable page.
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*/
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wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
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pg = vmalloc_to_page(hv_hypercall_pg);
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dst = kmap(pg);
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src = memremap(hypercall_msr.guest_physical_address << PAGE_SHIFT, PAGE_SIZE,
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MEMREMAP_WB);
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BUG_ON(!(src && dst));
|
|
memcpy(dst, src, HV_HYP_PAGE_SIZE);
|
|
memunmap(src);
|
|
kunmap(pg);
|
|
} else {
|
|
hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
|
|
wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
|
|
}
|
|
|
|
/*
|
|
* hyperv_init() is called before LAPIC is initialized: see
|
|
* apic_intr_mode_init() -> x86_platform.apic_post_init() and
|
|
* apic_bsp_setup() -> setup_local_APIC(). The direct-mode STIMER
|
|
* depends on LAPIC, so hv_stimer_alloc() should be called from
|
|
* x86_init.timers.setup_percpu_clockev.
|
|
*/
|
|
old_setup_percpu_clockev = x86_init.timers.setup_percpu_clockev;
|
|
x86_init.timers.setup_percpu_clockev = hv_stimer_setup_percpu_clockev;
|
|
|
|
hv_apic_init();
|
|
|
|
x86_init.pci.arch_init = hv_pci_init;
|
|
|
|
register_syscore_ops(&hv_syscore_ops);
|
|
|
|
hyperv_init_cpuhp = cpuhp;
|
|
|
|
if (cpuid_ebx(HYPERV_CPUID_FEATURES) & HV_ACCESS_PARTITION_ID)
|
|
hv_get_partition_id();
|
|
|
|
BUG_ON(hv_root_partition && hv_current_partition_id == ~0ull);
|
|
|
|
#ifdef CONFIG_PCI_MSI
|
|
/*
|
|
* If we're running as root, we want to create our own PCI MSI domain.
|
|
* We can't set this in hv_pci_init because that would be too late.
|
|
*/
|
|
if (hv_root_partition)
|
|
x86_init.irqs.create_pci_msi_domain = hv_create_pci_msi_domain;
|
|
#endif
|
|
|
|
/* Query the VMs extended capability once, so that it can be cached. */
|
|
hv_query_ext_cap(0);
|
|
|
|
#ifdef CONFIG_SWIOTLB
|
|
/*
|
|
* Swiotlb bounce buffer needs to be mapped in extra address
|
|
* space. Map function doesn't work in the early place and so
|
|
* call swiotlb_update_mem_attributes() here.
|
|
*/
|
|
if (hv_is_isolation_supported())
|
|
swiotlb_update_mem_attributes();
|
|
#endif
|
|
|
|
return;
|
|
|
|
clean_guest_os_id:
|
|
wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
|
|
hv_ghcb_msr_write(HV_X64_MSR_GUEST_OS_ID, 0);
|
|
cpuhp_remove_state(cpuhp);
|
|
free_ghcb_page:
|
|
free_percpu(hv_ghcb_pg);
|
|
free_vp_assist_page:
|
|
kfree(hv_vp_assist_page);
|
|
hv_vp_assist_page = NULL;
|
|
common_free:
|
|
hv_common_free();
|
|
}
|
|
|
|
/*
|
|
* This routine is called before kexec/kdump, it does the required cleanup.
|
|
*/
|
|
void hyperv_cleanup(void)
|
|
{
|
|
union hv_x64_msr_hypercall_contents hypercall_msr;
|
|
|
|
unregister_syscore_ops(&hv_syscore_ops);
|
|
|
|
/* 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,
|
|
* let hypercall operations fail safely rather than
|
|
* panic the kernel for using invalid hypercall page
|
|
*/
|
|
hv_hypercall_pg = NULL;
|
|
|
|
/* Reset the hypercall page */
|
|
hypercall_msr.as_uint64 = 0;
|
|
wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
|
|
|
|
/* Reset the TSC page */
|
|
hypercall_msr.as_uint64 = 0;
|
|
wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64);
|
|
}
|
|
|
|
void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die)
|
|
{
|
|
static bool panic_reported;
|
|
u64 guest_id;
|
|
|
|
if (in_die && !panic_on_oops)
|
|
return;
|
|
|
|
/*
|
|
* We prefer to report panic on 'die' chain as we have proper
|
|
* registers to report, but if we miss it (e.g. on BUG()) we need
|
|
* to report it on 'panic'.
|
|
*/
|
|
if (panic_reported)
|
|
return;
|
|
panic_reported = true;
|
|
|
|
rdmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
|
|
|
|
wrmsrl(HV_X64_MSR_CRASH_P0, err);
|
|
wrmsrl(HV_X64_MSR_CRASH_P1, guest_id);
|
|
wrmsrl(HV_X64_MSR_CRASH_P2, regs->ip);
|
|
wrmsrl(HV_X64_MSR_CRASH_P3, regs->ax);
|
|
wrmsrl(HV_X64_MSR_CRASH_P4, regs->sp);
|
|
|
|
/*
|
|
* Let Hyper-V know there is crash data available
|
|
*/
|
|
wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
|
|
}
|
|
EXPORT_SYMBOL_GPL(hyperv_report_panic);
|
|
|
|
bool hv_is_hyperv_initialized(void)
|
|
{
|
|
union hv_x64_msr_hypercall_contents hypercall_msr;
|
|
|
|
/*
|
|
* Ensure that we're really on Hyper-V, and not a KVM or Xen
|
|
* emulation of Hyper-V
|
|
*/
|
|
if (x86_hyper_type != X86_HYPER_MS_HYPERV)
|
|
return false;
|
|
|
|
/*
|
|
* Verify that earlier initialization succeeded by checking
|
|
* that the hypercall page is setup
|
|
*/
|
|
hypercall_msr.as_uint64 = 0;
|
|
rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
|
|
|
|
return hypercall_msr.enable;
|
|
}
|
|
EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);
|