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arm64: hyperv: Use SMCCC to detect hypervisor presence

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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>
This commit is contained in:
Roman Kisel 2025-04-28 14:07:33 -07:00 committed by Wei Liu
parent 13423063c7
commit 36ebd328a5
1 changed files with 45 additions and 5 deletions
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50
arch/arm64/hyperv/mshyperv.c
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@ -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 */