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| author | Thomas Gleixner <tglx@linutronix.de> | 2022-01-05 04:35:13 -0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-01-07 13:33:03 -0500 |
| commit | 36487e6228c4cb04257c92266a04078a384bc4ec (patch) | |
| tree | cd483a6cc3916cf83f298614aad1507188979952 /arch/x86/kernel/fpu | |
| parent | 980fe2fddcff21937c93532b4597c8ea450346c1 (diff) | |
| download | lwn-36487e6228c4cb04257c92266a04078a384bc4ec.tar.gz lwn-36487e6228c4cb04257c92266a04078a384bc4ec.zip | |
x86/fpu: Prepare guest FPU for dynamically enabled FPU features
To support dynamically enabled FPU features for guests prepare the guest
pseudo FPU container to keep track of the currently enabled xfeatures and
the guest permissions.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jing Liu <jing2.liu@intel.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
Message-Id: <20220105123532.12586-3-yang.zhong@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kernel/fpu')
| -rw-r--r-- | arch/x86/kernel/fpu/core.c | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index ab19b3d8b2f7..eddeeb4ed2f5 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -201,6 +201,26 @@ void fpu_reset_from_exception_fixup(void) #if IS_ENABLED(CONFIG_KVM) static void __fpstate_reset(struct fpstate *fpstate); +static void fpu_init_guest_permissions(struct fpu_guest *gfpu) +{ + struct fpu_state_perm *fpuperm; + u64 perm; + + if (!IS_ENABLED(CONFIG_X86_64)) + return; + + spin_lock_irq(¤t->sighand->siglock); + fpuperm = ¤t->group_leader->thread.fpu.guest_perm; + perm = fpuperm->__state_perm; + + /* First fpstate allocation locks down permissions. */ + WRITE_ONCE(fpuperm->__state_perm, perm | FPU_GUEST_PERM_LOCKED); + + spin_unlock_irq(¤t->sighand->siglock); + + gfpu->perm = perm & ~FPU_GUEST_PERM_LOCKED; +} + bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu) { struct fpstate *fpstate; @@ -216,7 +236,11 @@ bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu) fpstate->is_valloc = true; fpstate->is_guest = true; - gfpu->fpstate = fpstate; + gfpu->fpstate = fpstate; + gfpu->xfeatures = fpu_user_cfg.default_features; + gfpu->perm = fpu_user_cfg.default_features; + fpu_init_guest_permissions(gfpu); + return true; } EXPORT_SYMBOL_GPL(fpu_alloc_guest_fpstate); |