cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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mshyperv.c (2211B)

      1// SPDX-License-Identifier: GPL-2.0
      2
      3/*
      4 * Core routines for interacting with Microsoft's Hyper-V hypervisor,
      5 * including hypervisor initialization.
      6 *
      7 * Copyright (C) 2021, Microsoft, Inc.
      8 *
      9 * Author : Michael Kelley <mikelley@microsoft.com>
     10 */
     11
     12#include <linux/types.h>
     13#include <linux/acpi.h>
     14#include <linux/export.h>
     15#include <linux/errno.h>
     16#include <linux/version.h>
     17#include <linux/cpuhotplug.h>
     18#include <asm/mshyperv.h>
     19
     20static bool hyperv_initialized;
     21
     22static int __init hyperv_init(void)
     23{
     24	struct hv_get_vp_registers_output	result;
     25	u32	a, b, c, d;
     26	u64	guest_id;
     27	int	ret;
     28
     29	/*
     30	 * Allow for a kernel built with CONFIG_HYPERV to be running in
     31	 * a non-Hyper-V environment, including on DT instead of ACPI.
     32	 * In such cases, do nothing and return success.
     33	 */
     34	if (acpi_disabled)
     35		return 0;
     36
     37	if (strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8))
     38		return 0;
     39
     40	/* Setup the guest ID */
     41	guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);
     42	hv_set_vpreg(HV_REGISTER_GUEST_OSID, guest_id);
     43
     44	/* Get the features and hints from Hyper-V */
     45	hv_get_vpreg_128(HV_REGISTER_FEATURES, &result);
     46	ms_hyperv.features = result.as32.a;
     47	ms_hyperv.priv_high = result.as32.b;
     48	ms_hyperv.misc_features = result.as32.c;
     49
     50	hv_get_vpreg_128(HV_REGISTER_ENLIGHTENMENTS, &result);
     51	ms_hyperv.hints = result.as32.a;
     52
     53	pr_info("Hyper-V: privilege flags low 0x%x, high 0x%x, hints 0x%x, misc 0x%x\n",
     54		ms_hyperv.features, ms_hyperv.priv_high, ms_hyperv.hints,
     55		ms_hyperv.misc_features);
     56
     57	/* Get information about the Hyper-V host version */
     58	hv_get_vpreg_128(HV_REGISTER_HYPERVISOR_VERSION, &result);
     59	a = result.as32.a;
     60	b = result.as32.b;
     61	c = result.as32.c;
     62	d = result.as32.d;
     63	pr_info("Hyper-V: Host Build %d.%d.%d.%d-%d-%d\n",
     64		b >> 16, b & 0xFFFF, a,	d & 0xFFFFFF, c, d >> 24);
     65
     66	ret = hv_common_init();
     67	if (ret)
     68		return ret;
     69
     70	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "arm64/hyperv_init:online",
     71				hv_common_cpu_init, hv_common_cpu_die);
     72	if (ret < 0) {
     73		hv_common_free();
     74		return ret;
     75	}
     76
     77	hyperv_initialized = true;
     78	return 0;
     79}
     80
     81early_initcall(hyperv_init);
     82
     83bool hv_is_hyperv_initialized(void)
     84{
     85	return hyperv_initialized;
     86}
     87EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);