diff options
Diffstat (limited to 'arch/x86/kernel/fpu/xstate.c')
| -rw-r--r-- | arch/x86/kernel/fpu/xstate.c | 59 |
1 files changed, 43 insertions, 16 deletions
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 9aa9ac8399ae..28e4fd65c9da 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -57,7 +57,7 @@ static const char *xfeature_names[] = "Protection Keys User registers", "PASID state", "Control-flow User registers", - "Control-flow Kernel registers (unused)", + "Control-flow Kernel registers (KVM only)", "unknown xstate feature", "unknown xstate feature", "unknown xstate feature", @@ -81,6 +81,7 @@ static unsigned short xsave_cpuid_features[] __initdata = { [XFEATURE_PKRU] = X86_FEATURE_OSPKE, [XFEATURE_PASID] = X86_FEATURE_ENQCMD, [XFEATURE_CET_USER] = X86_FEATURE_SHSTK, + [XFEATURE_CET_KERNEL] = X86_FEATURE_SHSTK, [XFEATURE_XTILE_CFG] = X86_FEATURE_AMX_TILE, [XFEATURE_XTILE_DATA] = X86_FEATURE_AMX_TILE, [XFEATURE_APX] = X86_FEATURE_APX, @@ -372,6 +373,7 @@ static __init void os_xrstor_booting(struct xregs_state *xstate) XFEATURE_MASK_BNDCSR | \ XFEATURE_MASK_PASID | \ XFEATURE_MASK_CET_USER | \ + XFEATURE_MASK_CET_KERNEL | \ XFEATURE_MASK_XTILE | \ XFEATURE_MASK_APX) @@ -573,6 +575,7 @@ static bool __init check_xstate_against_struct(int nr) case XFEATURE_PASID: return XCHECK_SZ(sz, nr, struct ia32_pasid_state); case XFEATURE_XTILE_CFG: return XCHECK_SZ(sz, nr, struct xtile_cfg); case XFEATURE_CET_USER: return XCHECK_SZ(sz, nr, struct cet_user_state); + case XFEATURE_CET_KERNEL: return XCHECK_SZ(sz, nr, struct cet_supervisor_state); case XFEATURE_APX: return XCHECK_SZ(sz, nr, struct apx_state); case XFEATURE_XTILE_DATA: check_xtile_data_against_struct(sz); return true; default: @@ -743,6 +746,9 @@ static int __init init_xstate_size(void) fpu_user_cfg.default_size = xstate_calculate_size(fpu_user_cfg.default_features, false); + guest_default_cfg.size = + xstate_calculate_size(guest_default_cfg.features, compacted); + return 0; } @@ -763,6 +769,7 @@ static void __init fpu__init_disable_system_xstate(unsigned int legacy_size) fpu_kernel_cfg.default_size = legacy_size; fpu_user_cfg.max_size = legacy_size; fpu_user_cfg.default_size = legacy_size; + guest_default_cfg.size = legacy_size; /* * Prevent enabling the static branch which enables writes to the @@ -773,6 +780,24 @@ static void __init fpu__init_disable_system_xstate(unsigned int legacy_size) fpstate_reset(x86_task_fpu(current)); } +static u64 __init host_default_mask(void) +{ + /* + * Exclude dynamic features (require userspace opt-in) and features + * that are supported only for KVM guests. + */ + return ~((u64)XFEATURE_MASK_USER_DYNAMIC | XFEATURE_MASK_GUEST_SUPERVISOR); +} + +static u64 __init guest_default_mask(void) +{ + /* + * Exclude dynamic features, which require userspace opt-in even + * for KVM guests. + */ + return ~(u64)XFEATURE_MASK_USER_DYNAMIC; +} + /* * Enable and initialize the xsave feature. * Called once per system bootup. @@ -855,12 +880,13 @@ void __init fpu__init_system_xstate(unsigned int legacy_size) fpu_user_cfg.max_features = fpu_kernel_cfg.max_features; fpu_user_cfg.max_features &= XFEATURE_MASK_USER_SUPPORTED; - /* Clean out dynamic features from default */ - fpu_kernel_cfg.default_features = fpu_kernel_cfg.max_features; - fpu_kernel_cfg.default_features &= ~XFEATURE_MASK_USER_DYNAMIC; - - fpu_user_cfg.default_features = fpu_user_cfg.max_features; - fpu_user_cfg.default_features &= ~XFEATURE_MASK_USER_DYNAMIC; + /* + * Now, given maximum feature set, determine default values by + * applying default masks. + */ + fpu_kernel_cfg.default_features = fpu_kernel_cfg.max_features & host_default_mask(); + fpu_user_cfg.default_features = fpu_user_cfg.max_features & host_default_mask(); + guest_default_cfg.features = fpu_kernel_cfg.max_features & guest_default_mask(); /* Store it for paranoia check at the end */ xfeatures = fpu_kernel_cfg.max_features; @@ -1855,19 +1881,20 @@ long fpu_xstate_prctl(int option, unsigned long arg2) #ifdef CONFIG_PROC_PID_ARCH_STATUS /* * Report the amount of time elapsed in millisecond since last AVX512 - * use in the task. + * use in the task. Report -1 if no AVX-512 usage. */ static void avx512_status(struct seq_file *m, struct task_struct *task) { - unsigned long timestamp = READ_ONCE(x86_task_fpu(task)->avx512_timestamp); - long delta; + unsigned long timestamp; + long delta = -1; - if (!timestamp) { - /* - * Report -1 if no AVX512 usage - */ - delta = -1; - } else { + /* AVX-512 usage is not tracked for kernel threads. Don't report anything. */ + if (task->flags & (PF_KTHREAD | PF_USER_WORKER)) + return; + + timestamp = READ_ONCE(x86_task_fpu(task)->avx512_timestamp); + + if (timestamp) { delta = (long)(jiffies - timestamp); /* * Cap to LONG_MAX if time difference > LONG_MAX |