Now that VMXON can be done without bouncing through KVM, do TDX-Module initialization during subsys init (specifically before module_init() so that it runs before KVM when both are built-in). Aside from the obvious benefits of separating core TDX code from KVM, this will allow tagging a pile of TDX functions and globals as being __init and __ro_after_init. Signed-off-by: Sean Christopherson --- Documentation/arch/x86/tdx.rst | 26 ----- arch/x86/include/asm/tdx.h | 4 - arch/x86/kvm/vmx/tdx.c | 169 ++++++-------------------------- arch/x86/virt/vmx/tdx/tdx.c | 170 ++++++++++++++++++--------------- arch/x86/virt/vmx/tdx/tdx.h | 8 -- 5 files changed, 124 insertions(+), 253 deletions(-) diff --git a/Documentation/arch/x86/tdx.rst b/Documentation/arch/x86/tdx.rst index 61670e7df2f7..2e0a15d6f7d1 100644 --- a/Documentation/arch/x86/tdx.rst +++ b/Documentation/arch/x86/tdx.rst @@ -60,32 +60,6 @@ Besides initializing the TDX module, a per-cpu initialization SEAMCALL must be done on one cpu before any other SEAMCALLs can be made on that cpu. -The kernel provides two functions, tdx_enable() and tdx_cpu_enable() to -allow the user of TDX to enable the TDX module and enable TDX on local -cpu respectively. - -Making SEAMCALL requires VMXON has been done on that CPU. Currently only -KVM implements VMXON. For now both tdx_enable() and tdx_cpu_enable() -don't do VMXON internally (not trivial), but depends on the caller to -guarantee that. - -To enable TDX, the caller of TDX should: 1) temporarily disable CPU -hotplug; 2) do VMXON and tdx_enable_cpu() on all online cpus; 3) call -tdx_enable(). For example:: - - cpus_read_lock(); - on_each_cpu(vmxon_and_tdx_cpu_enable()); - ret = tdx_enable(); - cpus_read_unlock(); - if (ret) - goto no_tdx; - // TDX is ready to use - -And the caller of TDX must guarantee the tdx_cpu_enable() has been -successfully done on any cpu before it wants to run any other SEAMCALL. -A typical usage is do both VMXON and tdx_cpu_enable() in CPU hotplug -online callback, and refuse to online if tdx_cpu_enable() fails. - User can consult dmesg to see whether the TDX module has been initialized. If the TDX module is initialized successfully, dmesg shows something diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h index 6b338d7f01b7..a149740b24e8 100644 --- a/arch/x86/include/asm/tdx.h +++ b/arch/x86/include/asm/tdx.h @@ -145,8 +145,6 @@ static __always_inline u64 sc_retry(sc_func_t func, u64 fn, #define seamcall(_fn, _args) sc_retry(__seamcall, (_fn), (_args)) #define seamcall_ret(_fn, _args) sc_retry(__seamcall_ret, (_fn), (_args)) #define seamcall_saved_ret(_fn, _args) sc_retry(__seamcall_saved_ret, (_fn), (_args)) -int tdx_cpu_enable(void); -int tdx_enable(void); const char *tdx_dump_mce_info(struct mce *m); const struct tdx_sys_info *tdx_get_sysinfo(void); @@ -223,8 +221,6 @@ u64 tdh_phymem_page_wbinvd_tdr(struct tdx_td *td); u64 tdh_phymem_page_wbinvd_hkid(u64 hkid, struct page *page); #else static inline void tdx_init(void) { } -static inline int tdx_cpu_enable(void) { return -ENODEV; } -static inline int tdx_enable(void) { return -ENODEV; } static inline u32 tdx_get_nr_guest_keyids(void) { return 0; } static inline const char *tdx_dump_mce_info(struct mce *m) { return NULL; } static inline const struct tdx_sys_info *tdx_get_sysinfo(void) { return NULL; } diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 21e67a47ad4e..d0161dc3d184 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -59,7 +59,7 @@ module_param_named(tdx, enable_tdx, bool, 0444); #define TDX_SHARED_BIT_PWL_5 gpa_to_gfn(BIT_ULL(51)) #define TDX_SHARED_BIT_PWL_4 gpa_to_gfn(BIT_ULL(47)) -static enum cpuhp_state tdx_cpuhp_state; +static enum cpuhp_state tdx_cpuhp_state __ro_after_init; static const struct tdx_sys_info *tdx_sysinfo; @@ -3304,17 +3304,7 @@ int tdx_gmem_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn, bool is_private) static int tdx_online_cpu(unsigned int cpu) { - unsigned long flags; - int r; - - /* Sanity check CPU is already in post-VMXON */ - WARN_ON_ONCE(!(cr4_read_shadow() & X86_CR4_VMXE)); - - local_irq_save(flags); - r = tdx_cpu_enable(); - local_irq_restore(flags); - - return r; + return 0; } static int tdx_offline_cpu(unsigned int cpu) @@ -3353,51 +3343,6 @@ static int tdx_offline_cpu(unsigned int cpu) return -EBUSY; } -static void __do_tdx_cleanup(void) -{ - /* - * Once TDX module is initialized, it cannot be disabled and - * re-initialized again w/o runtime update (which isn't - * supported by kernel). Only need to remove the cpuhp here. - * The TDX host core code tracks TDX status and can handle - * 'multiple enabling' scenario. - */ - WARN_ON_ONCE(!tdx_cpuhp_state); - cpuhp_remove_state_nocalls_cpuslocked(tdx_cpuhp_state); - tdx_cpuhp_state = 0; -} - -static void __tdx_cleanup(void) -{ - cpus_read_lock(); - __do_tdx_cleanup(); - cpus_read_unlock(); -} - -static int __init __do_tdx_bringup(void) -{ - int r; - - /* - * TDX-specific cpuhp callback to call tdx_cpu_enable() on all - * online CPUs before calling tdx_enable(), and on any new - * going-online CPU to make sure it is ready for TDX guest. - */ - r = cpuhp_setup_state_cpuslocked(CPUHP_AP_ONLINE_DYN, - "kvm/cpu/tdx:online", - tdx_online_cpu, tdx_offline_cpu); - if (r < 0) - return r; - - tdx_cpuhp_state = r; - - r = tdx_enable(); - if (r) - __do_tdx_cleanup(); - - return r; -} - static int __init __tdx_bringup(void) { const struct tdx_sys_info_td_conf *td_conf; @@ -3417,34 +3362,18 @@ static int __init __tdx_bringup(void) } } - /* - * Enabling TDX requires enabling hardware virtualization first, - * as making SEAMCALLs requires CPU being in post-VMXON state. - */ - r = kvm_enable_virtualization(); - if (r) - return r; - - cpus_read_lock(); - r = __do_tdx_bringup(); - cpus_read_unlock(); - - if (r) - goto tdx_bringup_err; - - r = -EINVAL; /* Get TDX global information for later use */ tdx_sysinfo = tdx_get_sysinfo(); - if (WARN_ON_ONCE(!tdx_sysinfo)) - goto get_sysinfo_err; + if (!tdx_sysinfo) + return -EINVAL; /* Check TDX module and KVM capabilities */ if (!tdx_get_supported_attrs(&tdx_sysinfo->td_conf) || !tdx_get_supported_xfam(&tdx_sysinfo->td_conf)) - goto get_sysinfo_err; + return -EINVAL; if (!(tdx_sysinfo->features.tdx_features0 & MD_FIELD_ID_FEATURES0_TOPOLOGY_ENUM)) - goto get_sysinfo_err; + return -EINVAL; /* * TDX has its own limit of maximum vCPUs it can support for all @@ -3479,34 +3408,31 @@ static int __init __tdx_bringup(void) if (td_conf->max_vcpus_per_td < num_present_cpus()) { pr_err("Disable TDX: MAX_VCPU_PER_TD (%u) smaller than number of logical CPUs (%u).\n", td_conf->max_vcpus_per_td, num_present_cpus()); - goto get_sysinfo_err; + return -EINVAL; } if (misc_cg_set_capacity(MISC_CG_RES_TDX, tdx_get_nr_guest_keyids())) - goto get_sysinfo_err; + return -EINVAL; /* - * Leave hardware virtualization enabled after TDX is enabled - * successfully. TDX CPU hotplug depends on this. + * TDX-specific cpuhp callback to disallow offlining the last CPU in a + * packing while KVM is running one or more TDs. Reclaiming HKIDs + * requires doing PAGE.WBINVD on every package, i.e. offlining all CPUs + * of a package would prevent reclaiming the HKID. */ + r = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "kvm/cpu/tdx:online", + tdx_online_cpu, tdx_offline_cpu); + if (r < 0) + goto err_cpuhup; + + tdx_cpuhp_state = r; return 0; -get_sysinfo_err: - __tdx_cleanup(); -tdx_bringup_err: - kvm_disable_virtualization(); +err_cpuhup: + misc_cg_set_capacity(MISC_CG_RES_TDX, 0); return r; } -void tdx_cleanup(void) -{ - if (enable_tdx) { - misc_cg_set_capacity(MISC_CG_RES_TDX, 0); - __tdx_cleanup(); - kvm_disable_virtualization(); - } -} - int __init tdx_bringup(void) { int r, i; @@ -3538,56 +3464,14 @@ int __init tdx_bringup(void) goto success_disable_tdx; } - if (!cpu_feature_enabled(X86_FEATURE_MOVDIR64B)) { - pr_err("tdx: MOVDIR64B is required for TDX\n"); - goto success_disable_tdx; - } - - if (!cpu_feature_enabled(X86_FEATURE_SELFSNOOP)) { - pr_err("Self-snoop is required for TDX\n"); - goto success_disable_tdx; - } - if (!cpu_feature_enabled(X86_FEATURE_TDX_HOST_PLATFORM)) { - pr_err("tdx: no TDX private KeyIDs available\n"); + pr_err("TDX not supported by the host platform\n"); goto success_disable_tdx; } - if (!enable_virt_at_load) { - pr_err("tdx: tdx requires kvm.enable_virt_at_load=1\n"); - goto success_disable_tdx; - } - - /* - * Ideally KVM should probe whether TDX module has been loaded - * first and then try to bring it up. But TDX needs to use SEAMCALL - * to probe whether the module is loaded (there is no CPUID or MSR - * for that), and making SEAMCALL requires enabling virtualization - * first, just like the rest steps of bringing up TDX module. - * - * So, for simplicity do everything in __tdx_bringup(); the first - * SEAMCALL will return -ENODEV when the module is not loaded. The - * only complication is having to make sure that initialization - * SEAMCALLs don't return TDX_SEAMCALL_VMFAILINVALID in other - * cases. - */ r = __tdx_bringup(); - if (r) { - /* - * Disable TDX only but don't fail to load module if the TDX - * module could not be loaded. No need to print message saying - * "module is not loaded" because it was printed when the first - * SEAMCALL failed. Don't bother unwinding the S-EPT hooks or - * vm_size, as kvm_x86_ops have already been finalized (and are - * intentionally not exported). The S-EPT code is unreachable, - * and allocating a few more bytes per VM in a should-be-rare - * failure scenario is a non-issue. - */ - if (r == -ENODEV) - goto success_disable_tdx; - + if (r) enable_tdx = 0; - } return r; @@ -3596,6 +3480,15 @@ int __init tdx_bringup(void) return 0; } +void tdx_cleanup(void) +{ + if (!enable_tdx) + return; + + misc_cg_set_capacity(MISC_CG_RES_TDX, 0); + cpuhp_remove_state(tdx_cpuhp_state); +} + void __init tdx_hardware_setup(void) { KVM_SANITY_CHECK_VM_STRUCT_SIZE(kvm_tdx); diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c index eac403248462..8282c9b1b48b 100644 --- a/arch/x86/virt/vmx/tdx/tdx.c +++ b/arch/x86/virt/vmx/tdx/tdx.c @@ -28,6 +28,7 @@ #include #include #include +#include #include #include #include @@ -38,6 +39,7 @@ #include #include #include +#include #include "tdx.h" static u32 tdx_global_keyid __ro_after_init; @@ -50,13 +52,11 @@ static DEFINE_PER_CPU(bool, tdx_lp_initialized); static struct tdmr_info_list tdx_tdmr_list; -static enum tdx_module_status_t tdx_module_status; -static DEFINE_MUTEX(tdx_module_lock); - /* All TDX-usable memory regions. Protected by mem_hotplug_lock. */ static LIST_HEAD(tdx_memlist); static struct tdx_sys_info tdx_sysinfo; +static bool tdx_module_initialized; typedef void (*sc_err_func_t)(u64 fn, u64 err, struct tdx_module_args *args); @@ -141,26 +141,15 @@ static int try_init_module_global(void) } /** - * tdx_cpu_enable - Enable TDX on local cpu - * - * Do one-time TDX module per-cpu initialization SEAMCALL (and TDX module - * global initialization SEAMCALL if not done) on local cpu to make this - * cpu be ready to run any other SEAMCALLs. - * - * Always call this function via IPI function calls. - * - * Return 0 on success, otherwise errors. + * Enable VMXON and then do one-time TDX module per-cpu initialization SEAMCALL + * (and TDX module global initialization SEAMCALL if not done) on local cpu to + * make this cpu be ready to run any other SEAMCALLs. */ -int tdx_cpu_enable(void) +static int tdx_cpu_enable(void) { struct tdx_module_args args = {}; int ret; - if (!boot_cpu_has(X86_FEATURE_TDX_HOST_PLATFORM)) - return -ENODEV; - - lockdep_assert_irqs_disabled(); - if (__this_cpu_read(tdx_lp_initialized)) return 0; @@ -181,7 +170,56 @@ int tdx_cpu_enable(void) return 0; } -EXPORT_SYMBOL_GPL(tdx_cpu_enable); + +static int tdx_online_cpu(unsigned int cpu) +{ + int ret; + + guard(irqsave)(); + + ret = x86_virt_get_cpu(X86_FEATURE_VMX); + if (ret) + return ret; + + ret = tdx_cpu_enable(); + if (ret) + x86_virt_put_cpu(X86_FEATURE_VMX); + + return ret; +} + +static int tdx_offline_cpu(unsigned int cpu) +{ + x86_virt_put_cpu(X86_FEATURE_VMX); + return 0; +} + +static void tdx_shutdown_cpu(void *ign) +{ + x86_virt_put_cpu(X86_FEATURE_VMX); +} + +static void tdx_shutdown(void) +{ + on_each_cpu(tdx_shutdown_cpu, NULL, 1); +} + +static int tdx_suspend(void) +{ + x86_virt_put_cpu(X86_FEATURE_VMX); + return 0; +} + +static void tdx_resume(void) +{ + WARN_ON_ONCE(x86_virt_get_cpu(X86_FEATURE_VMX)); +} + +static struct syscore_ops tdx_syscore_ops = { + .suspend = tdx_suspend, + .resume = tdx_resume, + .shutdown = tdx_shutdown, +}; /* * Add a memory region as a TDX memory block. The caller must make sure @@ -1156,67 +1194,50 @@ static int init_tdx_module(void) goto out_put_tdxmem; } -static int __tdx_enable(void) +static int tdx_enable(void) { + enum cpuhp_state state; int ret; + if (!cpu_feature_enabled(X86_FEATURE_TDX_HOST_PLATFORM)) { + pr_err("TDX not supported by the host platform\n"); + return -ENODEV; + } + + if (!cpu_feature_enabled(X86_FEATURE_XSAVE)) { + pr_err("XSAVE is required for TDX\n"); + return -EINVAL; + } + + if (!cpu_feature_enabled(X86_FEATURE_MOVDIR64B)) { + pr_err("MOVDIR64B is required for TDX\n"); + return -EINVAL; + } + + if (!cpu_feature_enabled(X86_FEATURE_SELFSNOOP)) { + pr_err("Self-snoop is required for TDX\n"); + return -ENODEV; + } + + state = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "virt/tdx:online", + tdx_online_cpu, tdx_offline_cpu); + if (state < 0) + return state; + ret = init_tdx_module(); if (ret) { - pr_err("module initialization failed (%d)\n", ret); - tdx_module_status = TDX_MODULE_ERROR; + pr_err("TDX-Module initialization failed (%d)\n", ret); + cpuhp_remove_state(state); return ret; } - pr_info("module initialized\n"); - tdx_module_status = TDX_MODULE_INITIALIZED; + register_syscore_ops(&tdx_syscore_ops); + tdx_module_initialized = true; + pr_info("TDX-Module initialized\n"); return 0; } - -/** - * tdx_enable - Enable TDX module to make it ready to run TDX guests - * - * This function assumes the caller has: 1) held read lock of CPU hotplug - * lock to prevent any new cpu from becoming online; 2) done both VMXON - * and tdx_cpu_enable() on all online cpus. - * - * This function requires there's at least one online cpu for each CPU - * package to succeed. - * - * This function can be called in parallel by multiple callers. - * - * Return 0 if TDX is enabled successfully, otherwise error. - */ -int tdx_enable(void) -{ - int ret; - - if (!boot_cpu_has(X86_FEATURE_TDX_HOST_PLATFORM)) - return -ENODEV; - - lockdep_assert_cpus_held(); - - mutex_lock(&tdx_module_lock); - - switch (tdx_module_status) { - case TDX_MODULE_UNINITIALIZED: - ret = __tdx_enable(); - break; - case TDX_MODULE_INITIALIZED: - /* Already initialized, great, tell the caller. */ - ret = 0; - break; - default: - /* Failed to initialize in the previous attempts */ - ret = -EINVAL; - break; - } - - mutex_unlock(&tdx_module_lock); - - return ret; -} -EXPORT_SYMBOL_GPL(tdx_enable); +subsys_initcall(tdx_enable); static bool is_pamt_page(unsigned long phys) { @@ -1467,15 +1488,10 @@ void __init tdx_init(void) const struct tdx_sys_info *tdx_get_sysinfo(void) { - const struct tdx_sys_info *p = NULL; + if (!tdx_module_initialized) + return NULL; - /* Make sure all fields in @tdx_sysinfo have been populated */ - mutex_lock(&tdx_module_lock); - if (tdx_module_status == TDX_MODULE_INITIALIZED) - p = (const struct tdx_sys_info *)&tdx_sysinfo; - mutex_unlock(&tdx_module_lock); - - return p; + return (const struct tdx_sys_info *)&tdx_sysinfo; } EXPORT_SYMBOL_GPL(tdx_get_sysinfo); diff --git a/arch/x86/virt/vmx/tdx/tdx.h b/arch/x86/virt/vmx/tdx/tdx.h index 82bb82be8567..dde219c823b4 100644 --- a/arch/x86/virt/vmx/tdx/tdx.h +++ b/arch/x86/virt/vmx/tdx/tdx.h @@ -91,14 +91,6 @@ struct tdmr_info { * Do not put any hardware-defined TDX structure representations below * this comment! */ - -/* Kernel defined TDX module status during module initialization. */ -enum tdx_module_status_t { - TDX_MODULE_UNINITIALIZED, - TDX_MODULE_INITIALIZED, - TDX_MODULE_ERROR -}; - struct tdx_memblock { struct list_head list; unsigned long start_pfn; -- 2.52.0.223.gf5cc29aaa4-goog