diff options
| author | Roman Kisel <romank@linux.microsoft.com> | 2025-04-28 14:07:33 -0700 |
|---|---|---|
| committer | Wei Liu <wei.liu@kernel.org> | 2025-05-23 16:30:55 +0000 |
| commit | 36ebd328a57ac6138470ecaea2f9ec0864e3db0f (patch) | |
| tree | 1c350d7e2e1ce19f4a7b57af547254ec57818edd | |
| parent | 13423063c7cb7d1c34104a78cae85eb0281bae90 (diff) | |
arm64: hyperv: Use SMCCC to detect hypervisor presence
The arm64 Hyper-V startup path relies on ACPI to detect
running under a Hyper-V compatible hypervisor. That
doesn't work on non-ACPI systems.
Hoist the ACPI detection logic into a separate function. Then
use the vendor-specific hypervisor service call (implemented
recently in Hyper-V) via SMCCC in the non-ACPI case.
Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/20250428210742.435282-3-romank@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <20250428210742.435282-3-romank@linux.microsoft.com>
| -rw-r--r-- | arch/arm64/hyperv/mshyperv.c | 50 |
1 files changed, 45 insertions, 5 deletions
diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c index 4e27cc29c79e..21458b6338aa 100644 --- a/arch/arm64/hyperv/mshyperv.c +++ b/arch/arm64/hyperv/mshyperv.c @@ -28,6 +28,48 @@ int hv_get_hypervisor_version(union hv_hypervisor_version_info *info) } EXPORT_SYMBOL_GPL(hv_get_hypervisor_version); +#ifdef CONFIG_ACPI + +static bool __init hyperv_detect_via_acpi(void) +{ + if (acpi_disabled) + return false; + /* + * Hypervisor ID is only available in ACPI v6+, and the + * structure layout was extended in v6 to accommodate that + * new field. + * + * At the very minimum, this check makes sure not to read + * past the FADT structure. + * + * It is also needed to catch running in some unknown + * non-Hyper-V environment that has ACPI 5.x or less. + * In such a case, it can't be Hyper-V. + */ + if (acpi_gbl_FADT.header.revision < 6) + return false; + return strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8) == 0; +} + +#else + +static bool __init hyperv_detect_via_acpi(void) +{ + return false; +} + +#endif + +static bool __init hyperv_detect_via_smccc(void) +{ + uuid_t hyperv_uuid = UUID_INIT( + 0x58ba324d, 0x6447, 0x24cd, + 0x75, 0x6c, 0xef, 0x8e, + 0x24, 0x70, 0x59, 0x16); + + return arm_smccc_hypervisor_has_uuid(&hyperv_uuid); +} + static int __init hyperv_init(void) { struct hv_get_vp_registers_output result; @@ -36,13 +78,11 @@ static int __init hyperv_init(void) /* * Allow for a kernel built with CONFIG_HYPERV to be running in - * a non-Hyper-V environment, including on DT instead of ACPI. + * a non-Hyper-V environment. + * * In such cases, do nothing and return success. */ - if (acpi_disabled) - return 0; - - if (strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8)) + if (!hyperv_detect_via_acpi() && !hyperv_detect_via_smccc()) return 0; /* Setup the guest ID */ |