Messages in this thread | | | Subject | Re: [PATCH v18 1/7] arm/arm64: Probe for the presence of KVM hypervisor | From | Steven Price <> | Date | Wed, 10 Feb 2021 16:07:46 +0000 |
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On 08/02/2021 13:40, Marc Zyngier wrote: > From: Will Deacon <will@kernel.org> > > 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. > > Signed-off-by: Will Deacon <will@kernel.org> > Signed-off-by: Jianyong Wu <jianyong.wu@arm.com> > [maz: move code to its own file, plug it into PSCI] > Signed-off-by: Marc Zyngier <maz@kernel.org> > Link: https://lore.kernel.org/r/20201209060932.212364-2-jianyong.wu@arm.com
Looks good to me, FWIW:
Reviewed-by: Steven Price <steven.price@arm.com>
> --- > arch/arm/include/asm/hypervisor.h | 3 ++ > arch/arm64/include/asm/hypervisor.h | 3 ++ > drivers/firmware/psci/psci.c | 2 ++ > drivers/firmware/smccc/Makefile | 2 +- > drivers/firmware/smccc/kvm_guest.c | 50 +++++++++++++++++++++++++++++ > drivers/firmware/smccc/smccc.c | 1 + > include/linux/arm-smccc.h | 25 +++++++++++++++ > 7 files changed, 85 insertions(+), 1 deletion(-) > create mode 100644 drivers/firmware/smccc/kvm_guest.c > > diff --git a/arch/arm/include/asm/hypervisor.h b/arch/arm/include/asm/hypervisor.h > index df8524365637..bd61502b9715 100644 > --- a/arch/arm/include/asm/hypervisor.h > +++ b/arch/arm/include/asm/hypervisor.h > @@ -4,4 +4,7 @@ > > #include <asm/xen/hypervisor.h> > > +void kvm_init_hyp_services(void); > +bool kvm_arm_hyp_service_available(u32 func_id); > + > #endif > diff --git a/arch/arm64/include/asm/hypervisor.h b/arch/arm64/include/asm/hypervisor.h > index f9cc1d021791..0ae427f352c8 100644 > --- a/arch/arm64/include/asm/hypervisor.h > +++ b/arch/arm64/include/asm/hypervisor.h > @@ -4,4 +4,7 @@ > > #include <asm/xen/hypervisor.h> > > +void kvm_init_hyp_services(void); > +bool kvm_arm_hyp_service_available(u32 func_id); > + > #endif > 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 <asm/cpuidle.h> > #include <asm/cputype.h> > +#include <asm/hypervisor.h> > #include <asm/system_misc.h> > #include <asm/smp_plat.h> > #include <asm/suspend.h> > @@ -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..08836f2f39ee > --- /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 <linux/arm-smccc.h> > +#include <linux/bitmap.h> > +#include <linux/kernel.h> > +#include <linux/string.h> > + > +#include <asm/hypervisor.h> > + > +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 -EINVAL; > + > + 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 00c88b809c0c..94eca6ffda05 100644 > --- a/drivers/firmware/smccc/smccc.c > +++ b/drivers/firmware/smccc/smccc.c > @@ -7,6 +7,7 @@ > > #include <linux/init.h> > #include <linux/arm-smccc.h> > +#include <linux/kernel.h> > > static u32 smccc_version = ARM_SMCCC_VERSION_1_0; > static enum arm_smccc_conduit smccc_conduit = SMCCC_CONDUIT_NONE; > diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h > index f860645f6512..74e90b65b489 100644 > --- a/include/linux/arm-smccc.h > +++ b/include/linux/arm-smccc.h > @@ -55,6 +55,8 @@ > #define ARM_SMCCC_OWNER_TRUSTED_OS 50 > #define ARM_SMCCC_OWNER_TRUSTED_OS_END 63 > > +#define ARM_SMCCC_FUNC_QUERY_CALL_UID 0xff01 > + > #define ARM_SMCCC_QUIRK_NONE 0 > #define ARM_SMCCC_QUIRK_QCOM_A6 1 /* Save/restore register a6 */ > > @@ -87,6 +89,29 @@ > ARM_SMCCC_SMC_32, \ > 0, 0x7fff) > > +#define ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID \ > + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ > + ARM_SMCCC_SMC_32, \ > + ARM_SMCCC_OWNER_VENDOR_HYP, \ > + ARM_SMCCC_FUNC_QUERY_CALL_UID) > + > +/* KVM UID value: 28b46fb6-2ec5-11e9-a9ca-4b564d003a74 */ > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0 0xb66fb428U > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1 0xe911c52eU > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2 0x564bcaa9U > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3 0x743a004dU > + > +/* KVM "vendor specific" services */ > +#define ARM_SMCCC_KVM_FUNC_FEATURES 0 > +#define ARM_SMCCC_KVM_FUNC_FEATURES_2 127 > +#define ARM_SMCCC_KVM_NUM_FUNCS 128 > + > +#define ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID \ > + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ > + ARM_SMCCC_SMC_32, \ > + ARM_SMCCC_OWNER_VENDOR_HYP, \ > + ARM_SMCCC_KVM_FUNC_FEATURES) > + > #define SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED 1 > > /* Paravirtualised time calls (defined by ARM DEN0057A) */ >
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