Re: [PATCH v11 3/5] arm64: hyperv: Initialize hypervisor on boot
From: Mark Rutland <mark.rutland@arm.com>
Date: 2021-08-02 16:26:31
Also in:
linux-efi, linux-hyperv, lkml
On Tue, Jul 20, 2021 at 07:57:01AM -0700, Michael Kelley wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- arch/arm64/hyperv/Makefile | 2 +- arch/arm64/hyperv/mshyperv.c | 83 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 84 insertions(+), 1 deletion(-) create mode 100644 arch/arm64/hyperv/mshyperv.cdiff --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.odiff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c new file mode 100644 index 0000000..2811fd0 --- /dev/null +++ b/arch/arm64/hyperv/mshyperv.c@@ -0,0 +1,83 @@ +// 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;
As Marc suggests, before looking at the FADT, you need something like: /* * Hyper-V VMs always have ACPI. */ if (acpi_disabled) return 0; ... where `acpi_disabled` is defined in <linux/acpi.h> (or via its includes), so you don't need to include any additional headers.
quoted hunk ↗ jump to hunk
+ + /* + * If we're in a VM on Hyper-V, the ACPI hypervisor_id field will + * have the string "MsHyperV". + */ + if (strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8)) + return -EINVAL;
As Marc suggests, it's no an error for a platform to not have Hyper-V, so returning 0 in tihs case would be preferable. Otherwise this looks fine to me. Thanks, Mark.
+
+ /* Setup the guest I[D */
+ 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);
--
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