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Commit a7d4b8f2 authored by David Hildenbrand's avatar David Hildenbrand Committed by Christian Borntraeger
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KVM: s390: don't use current->thread.fpu.* when accessing registers 



As the meaning of these variables and pointers seems to change more
frequently, let's directly access our save area, instead of going via
current->thread.

Right now, this is broken for set/get_fpu. They simply overwrite the
host registers, as the pointers to the current save area were turned
into the static host save area.

Cc: stable@vger.kernel.org # 4.7
Fixes: 3f6813b9 ("s390/fpu: allocate 'struct fpu' with the task_struct")
Reported-by: default avatarHao QingFeng <haoqf@linux.vnet.ibm.com>
Signed-off-by: default avatarDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent ba913e4f

arch/s390/kvm/kvm-s390.c

+6 −4
Original line number Diff line number Diff line
@@ -2231,9 +2231,10 @@ int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu) 
		return -EINVAL;

	current->thread.fpu.fpc = fpu->fpc;

	if (MACHINE_HAS_VX)

		convert_fp_to_vx(current->thread.fpu.vxrs, (freg_t *)fpu->fprs);

		convert_fp_to_vx((__vector128 *) vcpu->run->s.regs.vrs,

				 (freg_t *) fpu->fprs);

	else

		memcpy(current->thread.fpu.fprs, &fpu->fprs, sizeof(fpu->fprs));

		memcpy(vcpu->run->s.regs.fprs, &fpu->fprs, sizeof(fpu->fprs));

	return 0;

}
@@ -2242,9 +2243,10 @@ int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu) 
	/* make sure we have the latest values */

	save_fpu_regs();

	if (MACHINE_HAS_VX)

		convert_vx_to_fp((freg_t *)fpu->fprs, current->thread.fpu.vxrs);

		convert_vx_to_fp((freg_t *) fpu->fprs,

				 (__vector128 *) vcpu->run->s.regs.vrs);

	else

		memcpy(fpu->fprs, current->thread.fpu.fprs, sizeof(fpu->fprs));

		memcpy(fpu->fprs, vcpu->run->s.regs.fprs, sizeof(fpu->fprs));

	fpu->fpc = current->thread.fpu.fpc;

	return 0;

}