Commit 0781d60f authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

x86/fpu: Provide fpu_enable_guest_xfd_features() for KVM 



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: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarKevin Tian <kevin.tian@intel.com>
Signed-off-by: default avatarYang Zhong <yang.zhong@intel.com>
Reviewed-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220105123532.12586-8-yang.zhong@intel.com>
[Remove unnecessary 32-bit check. - Paolo]
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent c270ce39

arch/x86/include/asm/fpu/api.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

arch/x86/kernel/fpu/core.c

+22 −0
Original line number Diff line number Diff line
@@ -261,6 +261,28 @@ void fpu_free_guest_fpstate(struct fpu_guest *gfpu) 
}

EXPORT_SYMBOL_GPL(fpu_free_guest_fpstate);



/*

  * fpu_enable_guest_xfd_features - Check xfeatures against guest perm and enable

  * @guest_fpu:         Pointer to the guest FPU container

  * @xfeatures:         Features requested by guest CPUID

  *

  * Enable all dynamic xfeatures according to guest perm and requested CPUID.

  *

  * Return: 0 on success, error code otherwise

  */

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;



	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;