diff options
| -rw-r--r-- | arch/x86/include/asm/fpu/types.h | 26 | ||||
| -rw-r--r-- | arch/x86/kernel/fpu/core.c | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/fpu/init.c | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/fpu/xstate.c | 32 |
4 files changed, 54 insertions, 6 deletions
diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h index 1c94121acd3d..abd193a1a52e 100644 --- a/arch/x86/include/asm/fpu/types.h +++ b/arch/x86/include/asm/fpu/types.h @@ -552,6 +552,31 @@ struct fpu_guest { }; /* + * FPU state configuration data for fpu_guest. + * Initialized at boot time. Read only after init. + */ +struct vcpu_fpu_config { + /* + * @size: + * + * The default size of the register state buffer in guest FPUs. + * Includes all supported features except independent managed + * features and features which have to be requested by user space + * before usage. + */ + unsigned int size; + + /* + * @features: + * + * The default supported features bitmap in guest FPUs. Does not + * include independent managed features and features which have to + * be requested by user space before usage. + */ + u64 features; +}; + +/* * FPU state configuration data. Initialized at boot time. Read only after init. */ struct fpu_state_config { @@ -606,5 +631,6 @@ struct fpu_state_config { /* FPU state configuration information */ extern struct fpu_state_config fpu_kernel_cfg, fpu_user_cfg; +extern struct vcpu_fpu_config guest_default_cfg; #endif /* _ASM_X86_FPU_TYPES_H */ diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index ea138583dd92..aa7252323cdd 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -37,6 +37,7 @@ DEFINE_PER_CPU(u64, xfd_state); /* The FPU state configuration data for kernel and user space */ struct fpu_state_config fpu_kernel_cfg __ro_after_init; struct fpu_state_config fpu_user_cfg __ro_after_init; +struct vcpu_fpu_config guest_default_cfg __ro_after_init; /* * Represents the initial FPU state. It's mostly (but not completely) zeroes, diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c index 99db41bf9fa6..ff988b9ea39f 100644 --- a/arch/x86/kernel/fpu/init.c +++ b/arch/x86/kernel/fpu/init.c @@ -205,6 +205,7 @@ static void __init fpu__init_system_xstate_size_legacy(void) fpu_kernel_cfg.default_size = size; fpu_user_cfg.max_size = size; fpu_user_cfg.default_size = size; + guest_default_cfg.size = size; } /* diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 9aa9ac8399ae..7c5f9f1e0700 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -743,6 +743,9 @@ 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 +766,7 @@ 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 +777,21 @@ 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, which require userspace opt-in. */ + return ~(u64)XFEATURE_MASK_USER_DYNAMIC; +} + +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 +874,13 @@ 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; |