From 6e085e0ac9cf16298b5fefe0b1893f98ef765812 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Wed, 9 Dec 2020 14:09:24 +0800 Subject: arm/arm64: Probe for the presence of KVM hypervisor Although the SMCCC specification provides some limited functionality for describing the presence of hypervisor and firmware services, this is generally applicable only to functions designated as "Arm Architecture Service Functions" and no portable discovery mechanism is provided for standard hypervisor services, despite having a designated range of function identifiers reserved by the specification. In an attempt to avoid the need for additional firmware changes every time a new function is added, introduce a UID to identify the service provider as being compatible with KVM. Once this has been established, additional services can be discovered via a feature bitmap. Reviewed-by: Steven Price Signed-off-by: Will Deacon Signed-off-by: Jianyong Wu [maz: move code to its own file, plug it into PSCI] Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20201209060932.212364-2-jianyong.wu@arm.com --- drivers/firmware/psci/psci.c | 2 ++ drivers/firmware/smccc/Makefile | 2 +- drivers/firmware/smccc/kvm_guest.c | 50 ++++++++++++++++++++++++++++++++++++++ drivers/firmware/smccc/smccc.c | 1 + 4 files changed, 54 insertions(+), 1 deletion(-) create mode 100644 drivers/firmware/smccc/kvm_guest.c (limited to 'drivers/firmware') diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c index f5fc429cae3f..69e296f02902 100644 --- a/drivers/firmware/psci/psci.c +++ b/drivers/firmware/psci/psci.c @@ -23,6 +23,7 @@ #include #include +#include #include #include #include @@ -498,6 +499,7 @@ static int __init psci_probe(void) psci_init_cpu_suspend(); psci_init_system_suspend(); psci_init_system_reset2(); + kvm_init_hyp_services(); } return 0; diff --git a/drivers/firmware/smccc/Makefile b/drivers/firmware/smccc/Makefile index 72ab84042832..40d19144a860 100644 --- a/drivers/firmware/smccc/Makefile +++ b/drivers/firmware/smccc/Makefile @@ -1,4 +1,4 @@ # SPDX-License-Identifier: GPL-2.0 # -obj-$(CONFIG_HAVE_ARM_SMCCC_DISCOVERY) += smccc.o +obj-$(CONFIG_HAVE_ARM_SMCCC_DISCOVERY) += smccc.o kvm_guest.o obj-$(CONFIG_ARM_SMCCC_SOC_ID) += soc_id.o diff --git a/drivers/firmware/smccc/kvm_guest.c b/drivers/firmware/smccc/kvm_guest.c new file mode 100644 index 000000000000..2d3e866decaa --- /dev/null +++ b/drivers/firmware/smccc/kvm_guest.c @@ -0,0 +1,50 @@ +// SPDX-License-Identifier: GPL-2.0 + +#define pr_fmt(fmt) "smccc: KVM: " fmt + +#include +#include +#include +#include + +#include + +static DECLARE_BITMAP(__kvm_arm_hyp_services, ARM_SMCCC_KVM_NUM_FUNCS) __ro_after_init = { }; + +void __init kvm_init_hyp_services(void) +{ + struct arm_smccc_res res; + u32 val[4]; + + if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_HVC) + return; + + arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, &res); + if (res.a0 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0 || + res.a1 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1 || + res.a2 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2 || + res.a3 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3) + return; + + memset(&res, 0, sizeof(res)); + arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID, &res); + + val[0] = lower_32_bits(res.a0); + val[1] = lower_32_bits(res.a1); + val[2] = lower_32_bits(res.a2); + val[3] = lower_32_bits(res.a3); + + bitmap_from_arr32(__kvm_arm_hyp_services, val, ARM_SMCCC_KVM_NUM_FUNCS); + + pr_info("hypervisor services detected (0x%08lx 0x%08lx 0x%08lx 0x%08lx)\n", + res.a3, res.a2, res.a1, res.a0); +} + +bool kvm_arm_hyp_service_available(u32 func_id) +{ + if (func_id >= ARM_SMCCC_KVM_NUM_FUNCS) + return false; + + return test_bit(func_id, __kvm_arm_hyp_services); +} +EXPORT_SYMBOL_GPL(kvm_arm_hyp_service_available); diff --git a/drivers/firmware/smccc/smccc.c b/drivers/firmware/smccc/smccc.c index d52bfc5ed5e4..028f81d702cc 100644 --- a/drivers/firmware/smccc/smccc.c +++ b/drivers/firmware/smccc/smccc.c @@ -8,6 +8,7 @@ #include #include #include +#include #include static u32 smccc_version = ARM_SMCCC_VERSION_1_0; -- cgit v1.2.3