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-rw-r--r--arch/arm64/hyperv/Makefile2
-rw-r--r--arch/arm64/hyperv/hv_core.c181
-rw-r--r--arch/arm64/hyperv/mshyperv.c87
3 files changed, 270 insertions, 0 deletions
diff --git a/arch/arm64/hyperv/Makefile b/arch/arm64/hyperv/Makefile
new file mode 100644
index 000000000..87c31c001
--- /dev/null
+++ b/arch/arm64/hyperv/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-y := hv_core.o mshyperv.o
diff --git a/arch/arm64/hyperv/hv_core.c b/arch/arm64/hyperv/hv_core.c
new file mode 100644
index 000000000..b54c34793
--- /dev/null
+++ b/arch/arm64/hyperv/hv_core.c
@@ -0,0 +1,181 @@
+// 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);
diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c
new file mode 100644
index 000000000..a40645457
--- /dev/null
+++ b/arch/arm64/hyperv/mshyperv.c
@@ -0,0 +1,87 @@
+// 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 = hv_generate_guest_id(LINUX_VERSION_CODE);
+ 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);