2021-08-04 23:52:35 +08:00
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Low level utility routines for interacting with Hyper-V.
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*
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* Copyright (C) 2021, Microsoft, Inc.
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*
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* Author : Michael Kelley <mikelley@microsoft.com>
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*/
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#include <linux/types.h>
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#include <linux/export.h>
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#include <linux/mm.h>
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#include <linux/hyperv.h>
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#include <linux/arm-smccc.h>
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#include <linux/module.h>
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#include <asm-generic/bug.h>
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#include <asm/hyperv-tlfs.h>
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#include <asm/mshyperv.h>
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/*
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* hv_do_hypercall- Invoke the specified hypercall
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*/
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u64 hv_do_hypercall(u64 control, void *input, void *output)
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{
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struct arm_smccc_res res;
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u64 input_address;
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u64 output_address;
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input_address = input ? virt_to_phys(input) : 0;
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output_address = output ? virt_to_phys(output) : 0;
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arm_smccc_1_1_hvc(HV_FUNC_ID, control,
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input_address, output_address, &res);
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return res.a0;
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}
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EXPORT_SYMBOL_GPL(hv_do_hypercall);
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/*
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* hv_do_fast_hypercall8 -- Invoke the specified hypercall
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* with arguments in registers instead of physical memory.
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* Avoids the overhead of virt_to_phys for simple hypercalls.
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*/
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u64 hv_do_fast_hypercall8(u16 code, u64 input)
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{
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struct arm_smccc_res res;
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u64 control;
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control = (u64)code | HV_HYPERCALL_FAST_BIT;
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arm_smccc_1_1_hvc(HV_FUNC_ID, control, input, &res);
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return res.a0;
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}
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EXPORT_SYMBOL_GPL(hv_do_fast_hypercall8);
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/*
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* Set a single VP register to a 64-bit value.
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*/
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void hv_set_vpreg(u32 msr, u64 value)
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{
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struct arm_smccc_res res;
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arm_smccc_1_1_hvc(HV_FUNC_ID,
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HVCALL_SET_VP_REGISTERS | HV_HYPERCALL_FAST_BIT |
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HV_HYPERCALL_REP_COMP_1,
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HV_PARTITION_ID_SELF,
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HV_VP_INDEX_SELF,
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msr,
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0,
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value,
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0,
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&res);
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/*
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* Something is fundamentally broken in the hypervisor if
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* setting a VP register fails. There's really no way to
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* continue as a guest VM, so panic.
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*/
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BUG_ON(!hv_result_success(res.a0));
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}
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EXPORT_SYMBOL_GPL(hv_set_vpreg);
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/*
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* Get the value of a single VP register. One version
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* returns just 64 bits and another returns the full 128 bits.
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* The two versions are separate to avoid complicating the
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* calling sequence for the more frequently used 64 bit version.
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*/
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void hv_get_vpreg_128(u32 msr, struct hv_get_vp_registers_output *result)
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{
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struct arm_smccc_1_2_regs args;
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struct arm_smccc_1_2_regs res;
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args.a0 = HV_FUNC_ID;
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args.a1 = HVCALL_GET_VP_REGISTERS | HV_HYPERCALL_FAST_BIT |
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HV_HYPERCALL_REP_COMP_1;
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args.a2 = HV_PARTITION_ID_SELF;
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args.a3 = HV_VP_INDEX_SELF;
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args.a4 = msr;
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/*
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* Use the SMCCC 1.2 interface because the results are in registers
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* beyond X0-X3.
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*/
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arm_smccc_1_2_hvc(&args, &res);
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/*
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* Something is fundamentally broken in the hypervisor if
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* getting a VP register fails. There's really no way to
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* continue as a guest VM, so panic.
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*/
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BUG_ON(!hv_result_success(res.a0));
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result->as64.low = res.a6;
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result->as64.high = res.a7;
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}
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EXPORT_SYMBOL_GPL(hv_get_vpreg_128);
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u64 hv_get_vpreg(u32 msr)
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{
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struct hv_get_vp_registers_output output;
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hv_get_vpreg_128(msr, &output);
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return output.as64.low;
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}
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EXPORT_SYMBOL_GPL(hv_get_vpreg);
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2021-08-04 23:52:36 +08:00
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/*
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* hyperv_report_panic - report a panic to Hyper-V. This function uses
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* the older version of the Hyper-V interface that admittedly doesn't
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* pass enough information to be useful beyond just recording the
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* occurrence of a panic. The parallel hv_kmsg_dump() uses the
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* new interface that allows reporting 4 Kbytes of data, which is much
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* more useful. Hyper-V on ARM64 always supports the newer interface, but
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* we retain support for the older version because the sysadmin is allowed
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* to disable the newer version via sysctl in case of information security
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* concerns about the more verbose version.
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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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{
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static bool panic_reported;
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u64 guest_id;
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/* Don't report a panic to Hyper-V if we're not going to panic */
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if (in_die && !panic_on_oops)
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return;
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/*
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* We prefer to report panic on 'die' chain as we have proper
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* registers to report, but if we miss it (e.g. on BUG()) we need
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* to report it on 'panic'.
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*
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* Calling code in the 'die' and 'panic' paths ensures that only
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* one CPU is running this code, so no atomicity is needed.
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*/
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if (panic_reported)
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return;
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panic_reported = true;
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guest_id = hv_get_vpreg(HV_REGISTER_GUEST_OSID);
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/*
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* Hyper-V provides the ability to store only 5 values.
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* Pick the passed in error value, the guest_id, the PC,
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* and the SP.
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*/
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hv_set_vpreg(HV_REGISTER_CRASH_P0, err);
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hv_set_vpreg(HV_REGISTER_CRASH_P1, guest_id);
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hv_set_vpreg(HV_REGISTER_CRASH_P2, regs->pc);
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hv_set_vpreg(HV_REGISTER_CRASH_P3, regs->sp);
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hv_set_vpreg(HV_REGISTER_CRASH_P4, 0);
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/*
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* Let Hyper-V know there is crash data available
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*/
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hv_set_vpreg(HV_REGISTER_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
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}
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EXPORT_SYMBOL_GPL(hyperv_report_panic);
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