From: Sean Christopherson seanjc@google.com
Provide a wrapper for expanding the guest fpstate buffer according to requested xfeatures. KVM wants to call this wrapper to manage any dynamic xstate used by the guest.
Suggested-by: Sean Christopherson seanjc@google.com Signed-off-by: Sean Christopherson seanjc@google.com Signed-off-by: Kevin Tian kevin.tian@intel.com Signed-off-by: Yang Zhong yang.zhong@intel.com --- arch/x86/include/asm/fpu/api.h | 1 + arch/x86/kernel/fpu/core.c | 17 +++++++++++++++++ 2 files changed, 18 insertions(+)
diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h index d8c222290e68..1ed2a247a84e 100644 --- a/arch/x86/include/asm/fpu/api.h +++ b/arch/x86/include/asm/fpu/api.h @@ -138,6 +138,7 @@ extern inline u64 xstate_get_guest_group_perm(void); extern bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu); extern void fpu_free_guest_fpstate(struct fpu_guest *gfpu); extern int fpu_swap_kvm_fpstate(struct fpu_guest *gfpu, bool enter_guest); +extern int fpu_enable_guest_xfd_features(struct fpu_guest *guest_fpu, u64 xfeatures);
extern void fpu_copy_guest_fpstate_to_uabi(struct fpu_guest *gfpu, void *buf, unsigned int size, u32 pkru); extern int fpu_copy_uabi_to_guest_fpstate(struct fpu_guest *gfpu, const void *buf, u64 xcr0, u32 *vpkru); diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index a78bc547fc03..5b08d20a4005 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -261,6 +261,23 @@ void fpu_free_guest_fpstate(struct fpu_guest *gfpu) } EXPORT_SYMBOL_GPL(fpu_free_guest_fpstate);
+int fpu_enable_guest_xfd_features(struct fpu_guest *guest_fpu, u64 xfeatures) +{ + lockdep_assert_preemption_enabled(); + + /* Nothing to do if all requested features are already enabled. */ + xfeatures &= ~guest_fpu->xfeatures; + if (!xfeatures) + return 0; + + /* Dynamic xfeatures are not supported with 32-bit kernels. */ + if (!IS_ENABLED(CONFIG_X86_64)) + return 0; + + return __xfd_enable_feature(xfeatures, guest_fpu); +} +EXPORT_SYMBOL_GPL(fpu_enable_guest_xfd_features); + int fpu_swap_kvm_fpstate(struct fpu_guest *guest_fpu, bool enter_guest) { struct fpstate *guest_fps = guest_fpu->fpstate;