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, use the new SMC added recently to Hyper-V to use in the non-ACPI case. Signed-off-by: Roman Kisel <romank@xxxxxxxxxxxxxxxxxxx> --- arch/arm64/hyperv/mshyperv.c | 36 ++++++++++++++++++++++++++----- arch/arm64/include/asm/mshyperv.h | 5 +++++ 2 files changed, 36 insertions(+), 5 deletions(-) diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c index b1a4de4eee29..341f98312667 100644 --- a/arch/arm64/hyperv/mshyperv.c +++ b/arch/arm64/hyperv/mshyperv.c @@ -27,6 +27,34 @@ int hv_get_hypervisor_version(union hv_hypervisor_version_info *info) return 0; } +static bool hyperv_detect_via_acpi(void) +{ + if (acpi_disabled) + return false; +#if IS_ENABLED(CONFIG_ACPI) + /* Hypervisor ID is only available in ACPI v6+. */ + if (acpi_gbl_FADT.header.revision < 6) + return false; + return strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8) == 0; +#else + return false; +#endif +} + +static bool hyperv_detect_via_smc(void) +{ + struct arm_smccc_res res = {}; + + if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_HVC) + return false; + arm_smccc_1_1_hvc(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, &res); + + return res.a0 == ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_0 && + res.a1 == ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_1 && + res.a2 == ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_2 && + res.a3 == ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_3; +} + static int __init hyperv_init(void) { struct hv_get_vp_registers_output result; @@ -35,13 +63,11 @@ 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_smc()) return 0; /* Setup the guest ID */ diff --git a/arch/arm64/include/asm/mshyperv.h b/arch/arm64/include/asm/mshyperv.h index a975e1a689dd..a7a3586f7cb1 100644 --- a/arch/arm64/include/asm/mshyperv.h +++ b/arch/arm64/include/asm/mshyperv.h @@ -51,4 +51,9 @@ static inline u64 hv_get_msr(unsigned int reg) #include <asm-generic/mshyperv.h> +#define ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_0 0x7948734d +#define ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_1 0x56726570 +#define ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_2 0 +#define ARM_SMCCC_VENDOR_HYP_UID_HYPERV_REG_3 0 + #endif -- 2.34.1