Add ARM64-specific code to initialize the Hyper-V
hypervisor when booting as a guest VM.
This code is built only when CONFIG_HYPERV is enabled.
Signed-off-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
Acked-by: Marc Zyngier <maz@xxxxxxxxxx>
Acked-by: Mark Rutland <mark.rutland@xxxxxxx>
---
arch/arm64/hyperv/Makefile | 2 +-
arch/arm64/hyperv/mshyperv.c | 87 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 88 insertions(+), 1 deletion(-)
create mode 100644 arch/arm64/hyperv/mshyperv.c
diff --git a/arch/arm64/hyperv/Makefile b/arch/arm64/hyperv/Makefile
index 1697d30..87c31c0 100644
--- a/arch/arm64/hyperv/Makefile
+++ b/arch/arm64/hyperv/Makefile
@@ -1,2 +1,2 @@
# SPDX-License-Identifier: GPL-2.0
-obj-y := hv_core.o
+obj-y := hv_core.o mshyperv.o
diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c
new file mode 100644
index 0000000..bbbe351
--- /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@xxxxxxxxxxxxx>
+ */
+
+#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);
--
1.8.3.1
