| Message ID | 9804cc9409d6773115e70bbb3bdc4adb67234cd6.1705965634.git.isaku.yamahata@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM TDX basic feature support | expand |
On 1/23/2024 7:52 AM, isaku.yamahata@intel.com wrote: > From: Isaku Yamahata <isaku.yamahata@intel.com> > > TDX requires several initialization steps for KVM to create guest TDs. > Detect CPU feature, enable VMX (TDX is based on VMX) on all online CPUs, > detect the TDX module availability, initialize it and disable VMX. > > To enable/disable VMX on all online CPUs, utilize > vmx_hardware_enable/disable(). The method also initializes each CPU for > TDX. TDX requires calling a TDX initialization function per logical > processor (LP) before the LP uses TDX. When the CPU is becoming online, > call the TDX LP initialization API. If it fails to initialize TDX, refuse > CPU online for simplicity instead of TDX avoiding the failed LP. > > There are several options on when to initialize the TDX module. A.) kernel > module loading time, B.) the first guest TD creation time. A.) was chosen. > With B.), a user may hit an error of the TDX initialization when trying to > create the first guest TD. The machine that fails to initialize the TDX > module can't boot any guest TD further. Such failure is undesirable and a > surprise because the user expects that the machine can accommodate guest > TD, but not. So A.) is better than B.). > > Introduce a module parameter, kvm_intel.tdx, to explicitly enable TDX KVM > support. It's off by default to keep the same behavior for those who don't > use TDX. Implement hardware_setup method to detect TDX feature of CPU and > initialize TDX module. > > Suggested-by: Sean Christopherson <seanjc@google.com> > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> > --- > v18: > - Added comment in vt_hardware_enable() by Binbin. > --- > arch/x86/kvm/Makefile | 1 + > arch/x86/kvm/vmx/main.c | 38 ++++++++++++++++- > arch/x86/kvm/vmx/tdx.c | 84 ++++++++++++++++++++++++++++++++++++++ > arch/x86/kvm/vmx/x86_ops.h | 8 ++++ > 4 files changed, 129 insertions(+), 2 deletions(-) > create mode 100644 arch/x86/kvm/vmx/tdx.c > > diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile > index 274df24b647f..5b85ef84b2e9 100644 > --- a/arch/x86/kvm/Makefile > +++ b/arch/x86/kvm/Makefile > @@ -24,6 +24,7 @@ kvm-intel-y += vmx/vmx.o vmx/vmenter.o vmx/pmu_intel.o vmx/vmcs12.o \ > > kvm-intel-$(CONFIG_X86_SGX_KVM) += vmx/sgx.o > kvm-intel-$(CONFIG_KVM_HYPERV) += vmx/hyperv.o vmx/hyperv_evmcs.o > +kvm-intel-$(CONFIG_INTEL_TDX_HOST) += vmx/tdx.o > > kvm-amd-y += svm/svm.o svm/vmenter.o svm/pmu.o svm/nested.o svm/avic.o \ > svm/sev.o > diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c > index 443db8ec5cd5..1e1feaacac59 100644 > --- a/arch/x86/kvm/vmx/main.c > +++ b/arch/x86/kvm/vmx/main.c > @@ -6,6 +6,40 @@ > #include "nested.h" > #include "pmu.h" > > +static bool enable_tdx __ro_after_init; > +module_param_named(tdx, enable_tdx, bool, 0444); > + > +static int vt_hardware_enable(void) > +{ > + int ret; > + > + ret = vmx_hardware_enable(); > + if (ret || !enable_tdx) > + return ret; > + > + ret = tdx_cpu_enable(); What's the reason for it? vt_hardware_setup() -> tdx_hardware_setup() -> on_each_cpu(vmx_tdx_on, &vmx_tdx, true); -> vmx_tdx_on() -> tdx_cpu_enable() ensures tdx_cpu_enable() is called once. No need to call it every vt_hardware_enable(). > + if (ret) > + /* > + * In error case, we keep the CPU offline in error case. So > + * need to revert VMXON. > + */ > + vmx_hardware_disable(); > + return ret; > +} > + > +static __init int vt_hardware_setup(void) > +{ > + int ret; > + > + ret = vmx_hardware_setup(); > + if (ret) > + return ret; > + > + enable_tdx = enable_tdx && !tdx_hardware_setup(&vt_x86_ops); > + > + return 0; > +} > + > #define VMX_REQUIRED_APICV_INHIBITS \ > (BIT(APICV_INHIBIT_REASON_DISABLE)| \ > BIT(APICV_INHIBIT_REASON_ABSENT) | \ > @@ -22,7 +56,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = { > > .hardware_unsetup = vmx_hardware_unsetup, > > - .hardware_enable = vmx_hardware_enable, > + .hardware_enable = vt_hardware_enable, > .hardware_disable = vmx_hardware_disable, > .has_emulated_msr = vmx_has_emulated_msr, > > @@ -161,7 +195,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = { > }; > > struct kvm_x86_init_ops vt_init_ops __initdata = { > - .hardware_setup = vmx_hardware_setup, > + .hardware_setup = vt_hardware_setup, > .handle_intel_pt_intr = NULL, > > .runtime_ops = &vt_x86_ops, > diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c > new file mode 100644 > index 000000000000..8a378fb6f1d4 > --- /dev/null > +++ b/arch/x86/kvm/vmx/tdx.c > @@ -0,0 +1,84 @@ > +// SPDX-License-Identifier: GPL-2.0 > +#include <linux/cpu.h> > + > +#include <asm/tdx.h> > + > +#include "capabilities.h" > +#include "x86_ops.h" > +#include "x86.h" > + > +#undef pr_fmt > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > + > +static int __init tdx_module_setup(void) > +{ > + int ret; > + > + ret = tdx_enable(); > + if (ret) { > + pr_info("Failed to initialize TDX module.\n"); > + return ret; > + } > + > + return 0; > +} > + > +struct vmx_tdx_enabled { the name is so confusing at first glance, ... > + cpumask_var_t vmx_enabled; > + atomic_t err; > +}; > + > +static void __init vmx_tdx_on(void *_vmx_tdx) so is this function name. > +{ > + struct vmx_tdx_enabled *vmx_tdx = _vmx_tdx; > + int r; > + > + r = vmx_hardware_enable(); > + if (!r) { > + cpumask_set_cpu(smp_processor_id(), vmx_tdx->vmx_enabled); > + r = tdx_cpu_enable(); > + } > + if (r) > + atomic_set(&vmx_tdx->err, r); > +} > + > +static void __init vmx_off(void *_vmx_enabled) > +{ > + cpumask_var_t *vmx_enabled = (cpumask_var_t *)_vmx_enabled; > + > + if (cpumask_test_cpu(smp_processor_id(), *vmx_enabled)) > + vmx_hardware_disable(); > +} > + > +int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops) > +{ > + struct vmx_tdx_enabled vmx_tdx = { > + .err = ATOMIC_INIT(0), > + }; > + int r = 0; > + > + if (!enable_ept) { > + pr_warn("Cannot enable TDX with EPT disabled\n"); > + return -EINVAL; > + } > + > + if (!zalloc_cpumask_var(&vmx_tdx.vmx_enabled, GFP_KERNEL)) { > + r = -ENOMEM; > + goto out; > + } > + > + /* tdx_enable() in tdx_module_setup() requires cpus lock. */ > + cpus_read_lock(); > + on_each_cpu(vmx_tdx_on, &vmx_tdx, true); /* TDX requires vmxon. */ > + r = atomic_read(&vmx_tdx.err); > + if (!r) > + r = tdx_module_setup(); > + else > + r = -EIO; > + on_each_cpu(vmx_off, &vmx_tdx.vmx_enabled, true); > + cpus_read_unlock(); > + free_cpumask_var(vmx_tdx.vmx_enabled); > + > +out: > + return r; > +} > diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h > index bca2d27b3dfd..b44cb681f74d 100644 > --- a/arch/x86/kvm/vmx/x86_ops.h > +++ b/arch/x86/kvm/vmx/x86_ops.h > @@ -18,6 +18,8 @@ bool kvm_is_vmx_supported(void); > int __init vmx_init(void); > void vmx_exit(void); > > +__init int vmx_hardware_setup(void); superfluous declaration. It's added in patch 4 already. > extern struct kvm_x86_ops vt_x86_ops __initdata; > extern struct kvm_x86_init_ops vt_init_ops __initdata; > > @@ -133,4 +135,10 @@ void vmx_cancel_hv_timer(struct kvm_vcpu *vcpu); > #endif > void vmx_setup_mce(struct kvm_vcpu *vcpu); > > +#ifdef CONFIG_INTEL_TDX_HOST > +int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops); > +#else > +static inline int tdx_hardware_setup(struct kvm_x86_ops *x86_ops) { return -EOPNOTSUPP; } > +#endif > + > #endif /* __KVM_X86_VMX_X86_OPS_H */
diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile index 274df24b647f..5b85ef84b2e9 100644 --- a/arch/x86/kvm/Makefile +++ b/arch/x86/kvm/Makefile @@ -24,6 +24,7 @@ kvm-intel-y += vmx/vmx.o vmx/vmenter.o vmx/pmu_intel.o vmx/vmcs12.o \ kvm-intel-$(CONFIG_X86_SGX_KVM) += vmx/sgx.o kvm-intel-$(CONFIG_KVM_HYPERV) += vmx/hyperv.o vmx/hyperv_evmcs.o +kvm-intel-$(CONFIG_INTEL_TDX_HOST) += vmx/tdx.o kvm-amd-y += svm/svm.o svm/vmenter.o svm/pmu.o svm/nested.o svm/avic.o \ svm/sev.o diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c index 443db8ec5cd5..1e1feaacac59 100644 --- a/arch/x86/kvm/vmx/main.c +++ b/arch/x86/kvm/vmx/main.c @@ -6,6 +6,40 @@ #include "nested.h" #include "pmu.h" +static bool enable_tdx __ro_after_init; +module_param_named(tdx, enable_tdx, bool, 0444); + +static int vt_hardware_enable(void) +{ + int ret; + + ret = vmx_hardware_enable(); + if (ret || !enable_tdx) + return ret; + + ret = tdx_cpu_enable(); + if (ret) + /* + * In error case, we keep the CPU offline in error case. So + * need to revert VMXON. + */ + vmx_hardware_disable(); + return ret; +} + +static __init int vt_hardware_setup(void) +{ + int ret; + + ret = vmx_hardware_setup(); + if (ret) + return ret; + + enable_tdx = enable_tdx && !tdx_hardware_setup(&vt_x86_ops); + + return 0; +} + #define VMX_REQUIRED_APICV_INHIBITS \ (BIT(APICV_INHIBIT_REASON_DISABLE)| \ BIT(APICV_INHIBIT_REASON_ABSENT) | \ @@ -22,7 +56,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = { .hardware_unsetup = vmx_hardware_unsetup, - .hardware_enable = vmx_hardware_enable, + .hardware_enable = vt_hardware_enable, .hardware_disable = vmx_hardware_disable, .has_emulated_msr = vmx_has_emulated_msr, @@ -161,7 +195,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = { }; struct kvm_x86_init_ops vt_init_ops __initdata = { - .hardware_setup = vmx_hardware_setup, + .hardware_setup = vt_hardware_setup, .handle_intel_pt_intr = NULL, .runtime_ops = &vt_x86_ops, diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c new file mode 100644 index 000000000000..8a378fb6f1d4 --- /dev/null +++ b/arch/x86/kvm/vmx/tdx.c @@ -0,0 +1,84 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/cpu.h> + +#include <asm/tdx.h> + +#include "capabilities.h" +#include "x86_ops.h" +#include "x86.h" + +#undef pr_fmt +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +static int __init tdx_module_setup(void) +{ + int ret; + + ret = tdx_enable(); + if (ret) { + pr_info("Failed to initialize TDX module.\n"); + return ret; + } + + return 0; +} + +struct vmx_tdx_enabled { + cpumask_var_t vmx_enabled; + atomic_t err; +}; + +static void __init vmx_tdx_on(void *_vmx_tdx) +{ + struct vmx_tdx_enabled *vmx_tdx = _vmx_tdx; + int r; + + r = vmx_hardware_enable(); + if (!r) { + cpumask_set_cpu(smp_processor_id(), vmx_tdx->vmx_enabled); + r = tdx_cpu_enable(); + } + if (r) + atomic_set(&vmx_tdx->err, r); +} + +static void __init vmx_off(void *_vmx_enabled) +{ + cpumask_var_t *vmx_enabled = (cpumask_var_t *)_vmx_enabled; + + if (cpumask_test_cpu(smp_processor_id(), *vmx_enabled)) + vmx_hardware_disable(); +} + +int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops) +{ + struct vmx_tdx_enabled vmx_tdx = { + .err = ATOMIC_INIT(0), + }; + int r = 0; + + if (!enable_ept) { + pr_warn("Cannot enable TDX with EPT disabled\n"); + return -EINVAL; + } + + if (!zalloc_cpumask_var(&vmx_tdx.vmx_enabled, GFP_KERNEL)) { + r = -ENOMEM; + goto out; + } + + /* tdx_enable() in tdx_module_setup() requires cpus lock. */ + cpus_read_lock(); + on_each_cpu(vmx_tdx_on, &vmx_tdx, true); /* TDX requires vmxon. */ + r = atomic_read(&vmx_tdx.err); + if (!r) + r = tdx_module_setup(); + else + r = -EIO; + on_each_cpu(vmx_off, &vmx_tdx.vmx_enabled, true); + cpus_read_unlock(); + free_cpumask_var(vmx_tdx.vmx_enabled); + +out: + return r; +} diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h index bca2d27b3dfd..b44cb681f74d 100644 --- a/arch/x86/kvm/vmx/x86_ops.h +++ b/arch/x86/kvm/vmx/x86_ops.h @@ -18,6 +18,8 @@ bool kvm_is_vmx_supported(void); int __init vmx_init(void); void vmx_exit(void); +__init int vmx_hardware_setup(void); + extern struct kvm_x86_ops vt_x86_ops __initdata; extern struct kvm_x86_init_ops vt_init_ops __initdata; @@ -133,4 +135,10 @@ void vmx_cancel_hv_timer(struct kvm_vcpu *vcpu); #endif void vmx_setup_mce(struct kvm_vcpu *vcpu); +#ifdef CONFIG_INTEL_TDX_HOST +int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops); +#else +static inline int tdx_hardware_setup(struct kvm_x86_ops *x86_ops) { return -EOPNOTSUPP; } +#endif + #endif /* __KVM_X86_VMX_X86_OPS_H */