Commit c07f1919 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'hyperv-next-signed-20210831' of... 

Merge tag 'hyperv-next-signed-20210831' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull hyperv updates from Wei Liu:

 - make Hyper-V code arch-agnostic (Michael Kelley)

 - fix sched_clock behaviour on Hyper-V (Ani Sinha)

 - fix a fault when Linux runs as the root partition on MSHV (Praveen
   Kumar)

 - fix VSS driver (Vitaly Kuznetsov)

 - cleanup (Sonia Sharma)

* tag 'hyperv-next-signed-20210831' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  hv_utils: Set the maximum packet size for VSS driver to the length of the receive buffer
  Drivers: hv: Enable Hyper-V code to be built on ARM64
  arm64: efi: Export screen_info
  arm64: hyperv: Initialize hypervisor on boot
  arm64: hyperv: Add panic handler
  arm64: hyperv: Add Hyper-V hypercall and register access utilities
  x86/hyperv: fix root partition faults when writing to VP assist page MSR
  hv: hyperv.h: Remove unused inline functions
  drivers: hv: Decouple Hyper-V clock/timer code from VMbus drivers
  x86/hyperv: add comment describing TSC_INVARIANT_CONTROL MSR setting bit 0
  Drivers: hv: Move Hyper-V misc functionality to arch-neutral code
  Drivers: hv: Add arch independent default functions for some Hyper-V handlers
  Drivers: hv: Make portions of Hyper-V init code be arch neutral
  x86/hyperv: fix for unwanted manipulation of sched_clock when TSC marked unstable
  asm-generic/hyperv: Add missing #include of nmi.h
parents 7c636d4d 9d68cd91

MAINTAINERS

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@@ -8647,6 +8647,9 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git 
F:	Documentation/ABI/stable/sysfs-bus-vmbus

F:	Documentation/ABI/testing/debugfs-hyperv

F:	Documentation/networking/device_drivers/ethernet/microsoft/netvsc.rst

F:	arch/arm64/hyperv

F:	arch/arm64/include/asm/hyperv-tlfs.h

F:	arch/arm64/include/asm/mshyperv.h

F:	arch/x86/hyperv

F:	arch/x86/include/asm/hyperv-tlfs.h

F:	arch/x86/include/asm/mshyperv.h

arch/arm64/Kbuild

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@@ -2,4 +2,5 @@ 
obj-y			+= kernel/ mm/ net/

obj-$(CONFIG_KVM)	+= kvm/

obj-$(CONFIG_XEN)	+= xen/

obj-$(subst m,y,$(CONFIG_HYPERV))	+= hyperv/

obj-$(CONFIG_CRYPTO)	+= crypto/

arch/arm64/hyperv/Makefile

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# SPDX-License-Identifier: GPL-2.0

obj-y		:= hv_core.o mshyperv.o

arch/arm64/hyperv/hv_core.c

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// SPDX-License-Identifier: GPL-2.0



/*

 * Low level utility routines for interacting with Hyper-V.

 *

 * Copyright (C) 2021, Microsoft, Inc.

 *

 * Author : Michael Kelley <mikelley@microsoft.com>

 */



#include <linux/types.h>

#include <linux/export.h>

#include <linux/mm.h>

#include <linux/hyperv.h>

#include <linux/arm-smccc.h>

#include <linux/module.h>

#include <asm-generic/bug.h>

#include <asm/hyperv-tlfs.h>

#include <asm/mshyperv.h>



/*

 * hv_do_hypercall- Invoke the specified hypercall

 */

u64 hv_do_hypercall(u64 control, void *input, void *output)

{

	struct arm_smccc_res	res;

	u64			input_address;

	u64			output_address;



	input_address = input ? virt_to_phys(input) : 0;

	output_address = output ? virt_to_phys(output) : 0;



	arm_smccc_1_1_hvc(HV_FUNC_ID, control,

			  input_address, output_address, &res);

	return res.a0;

}

EXPORT_SYMBOL_GPL(hv_do_hypercall);



/*

 * hv_do_fast_hypercall8 -- Invoke the specified hypercall

 * with arguments in registers instead of physical memory.

 * Avoids the overhead of virt_to_phys for simple hypercalls.

 */



u64 hv_do_fast_hypercall8(u16 code, u64 input)

{

	struct arm_smccc_res	res;

	u64			control;



	control = (u64)code | HV_HYPERCALL_FAST_BIT;



	arm_smccc_1_1_hvc(HV_FUNC_ID, control, input, &res);

	return res.a0;

}

EXPORT_SYMBOL_GPL(hv_do_fast_hypercall8);



/*

 * Set a single VP register to a 64-bit value.

 */

void hv_set_vpreg(u32 msr, u64 value)

{

	struct arm_smccc_res res;



	arm_smccc_1_1_hvc(HV_FUNC_ID,

		HVCALL_SET_VP_REGISTERS | HV_HYPERCALL_FAST_BIT |

			HV_HYPERCALL_REP_COMP_1,

		HV_PARTITION_ID_SELF,

		HV_VP_INDEX_SELF,

		msr,

		0,

		value,

		0,

		&res);



	/*

	 * Something is fundamentally broken in the hypervisor if

	 * setting a VP register fails. There's really no way to

	 * continue as a guest VM, so panic.

	 */

	BUG_ON(!hv_result_success(res.a0));

}

EXPORT_SYMBOL_GPL(hv_set_vpreg);



/*

 * Get the value of a single VP register.  One version

 * returns just 64 bits and another returns the full 128 bits.

 * The two versions are separate to avoid complicating the

 * calling sequence for the more frequently used 64 bit version.

 */



void hv_get_vpreg_128(u32 msr, struct hv_get_vp_registers_output *result)

{

	struct arm_smccc_1_2_regs args;

	struct arm_smccc_1_2_regs res;



	args.a0 = HV_FUNC_ID;

	args.a1 = HVCALL_GET_VP_REGISTERS | HV_HYPERCALL_FAST_BIT |

			HV_HYPERCALL_REP_COMP_1;

	args.a2 = HV_PARTITION_ID_SELF;

	args.a3 = HV_VP_INDEX_SELF;

	args.a4 = msr;



	/*

	 * Use the SMCCC 1.2 interface because the results are in registers

	 * beyond X0-X3.

	 */

	arm_smccc_1_2_hvc(&args, &res);



	/*

	 * Something is fundamentally broken in the hypervisor if

	 * getting a VP register fails. There's really no way to

	 * continue as a guest VM, so panic.

	 */

	BUG_ON(!hv_result_success(res.a0));



	result->as64.low = res.a6;

	result->as64.high = res.a7;

}

EXPORT_SYMBOL_GPL(hv_get_vpreg_128);



u64 hv_get_vpreg(u32 msr)

{

	struct hv_get_vp_registers_output output;



	hv_get_vpreg_128(msr, &output);



	return output.as64.low;

}

EXPORT_SYMBOL_GPL(hv_get_vpreg);



/*

 * hyperv_report_panic - report a panic to Hyper-V.  This function uses

 * the older version of the Hyper-V interface that admittedly doesn't

 * pass enough information to be useful beyond just recording the

 * occurrence of a panic. The parallel hv_kmsg_dump() uses the

 * new interface that allows reporting 4 Kbytes of data, which is much

 * more useful. Hyper-V on ARM64 always supports the newer interface, but

 * we retain support for the older version because the sysadmin is allowed

 * to disable the newer version via sysctl in case of information security

 * concerns about the more verbose version.

 */

void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die)

{

	static bool	panic_reported;

	u64		guest_id;



	/* Don't report a panic to Hyper-V if we're not going to panic */

	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'.

	 *

	 * Calling code in the 'die' and 'panic' paths ensures that only

	 * one CPU is running this code, so no atomicity is needed.

	 */

	if (panic_reported)

		return;

	panic_reported = true;



	guest_id = hv_get_vpreg(HV_REGISTER_GUEST_OSID);



	/*

	 * Hyper-V provides the ability to store only 5 values.

	 * Pick the passed in error value, the guest_id, the PC,

	 * and the SP.

	 */

	hv_set_vpreg(HV_REGISTER_CRASH_P0, err);

	hv_set_vpreg(HV_REGISTER_CRASH_P1, guest_id);

	hv_set_vpreg(HV_REGISTER_CRASH_P2, regs->pc);

	hv_set_vpreg(HV_REGISTER_CRASH_P3, regs->sp);

	hv_set_vpreg(HV_REGISTER_CRASH_P4, 0);



	/*

	 * Let Hyper-V know there is crash data available

	 */

	hv_set_vpreg(HV_REGISTER_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);

}

EXPORT_SYMBOL_GPL(hyperv_report_panic);

arch/arm64/hyperv/mshyperv.c

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// SPDX-License-Identifier: GPL-2.0



/*

 * Core routines for interacting with Microsoft's Hyper-V hypervisor,

 * including hypervisor initialization.

 *

 * Copyright (C) 2021, Microsoft, Inc.

 *

 * Author : Michael Kelley <mikelley@microsoft.com>

 */



#include <linux/types.h>

#include <linux/acpi.h>

#include <linux/export.h>

#include <linux/errno.h>

#include <linux/version.h>

#include <linux/cpuhotplug.h>

#include <asm/mshyperv.h>



static bool hyperv_initialized;



static int __init hyperv_init(void)

{

	struct hv_get_vp_registers_output	result;

	u32	a, b, c, d;

	u64	guest_id;

	int	ret;



	/*

	 * Allow for a kernel built with CONFIG_HYPERV to be running in

	 * a non-Hyper-V environment, including on DT instead of ACPI.

	 * In such cases, do nothing and return success.

	 */

	if (acpi_disabled)

		return 0;



	if (strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8))

		return 0;



	/* Setup the guest ID */

	guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);

	hv_set_vpreg(HV_REGISTER_GUEST_OSID, guest_id);



	/* Get the features and hints from Hyper-V */

	hv_get_vpreg_128(HV_REGISTER_FEATURES, &result);

	ms_hyperv.features = result.as32.a;

	ms_hyperv.priv_high = result.as32.b;

	ms_hyperv.misc_features = result.as32.c;



	hv_get_vpreg_128(HV_REGISTER_ENLIGHTENMENTS, &result);

	ms_hyperv.hints = result.as32.a;



	pr_info("Hyper-V: privilege flags low 0x%x, high 0x%x, hints 0x%x, misc 0x%x\n",

		ms_hyperv.features, ms_hyperv.priv_high, ms_hyperv.hints,

		ms_hyperv.misc_features);



	/* Get information about the Hyper-V host version */

	hv_get_vpreg_128(HV_REGISTER_HYPERVISOR_VERSION, &result);

	a = result.as32.a;

	b = result.as32.b;

	c = result.as32.c;

	d = result.as32.d;

	pr_info("Hyper-V: Host Build %d.%d.%d.%d-%d-%d\n",

		b >> 16, b & 0xFFFF, a,	d & 0xFFFFFF, c, d >> 24);



	ret = hv_common_init();

	if (ret)

		return ret;



	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "arm64/hyperv_init:online",

				hv_common_cpu_init, hv_common_cpu_die);

	if (ret < 0) {

		hv_common_free();

		return ret;

	}



	hyperv_initialized = true;

	return 0;

}



early_initcall(hyperv_init);



bool hv_is_hyperv_initialized(void)

{

	return hyperv_initialized;

}

EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);