KVM: s390: Allocate and save/restore vector registers

Define and allocate space for both the host and guest views of
the vector registers for a given vcpu.  The 32 vector registers
occupy 128 bits each (512 bytes total), but architecturally are
paired with 512 additional bytes of reserved space for future
expansion.

The kvm_sync_regs structs containing the registers are union'ed
with 1024 bytes of padding in the common kvm_run struct.  The
addition of 1024 bytes of new register information clearly exceeds
the existing union, so an expansion of that padding is required.

When changing environments, we need to appropriately save and
restore the vector registers viewed by both the host and guest,
into and out of the sync_regs space.

The floating point registers overlay the upper half of vector
registers 0-15, so there's a bit of data duplication here that
needs to be carefully avoided.

Signed-off-by: Eric Farman <farman@linux.vnet.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

1 files changed, 33 insertions, 6 deletions

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index f3517e716fa4..a8fe3ab76d68 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -185,6 +185,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_S390_COW:
 		r = MACHINE_HAS_ESOP;
 		break;
+	case KVM_CAP_S390_VECTOR_REGISTERS:
+		r = MACHINE_HAS_VX;
+		break;
 	default:
 		r = 0;
 	}
@@ -265,6 +268,10 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
 		kvm->arch.user_sigp = 1;
 		r = 0;
 		break;
+	case KVM_CAP_S390_VECTOR_REGISTERS:
+		kvm->arch.use_vectors = MACHINE_HAS_VX;
+		r = MACHINE_HAS_VX ? 0 : -EINVAL;
+		break;
 	default:
 		r = -EINVAL;
 		break;
@@ -942,6 +949,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 
 	kvm->arch.css_support = 0;
 	kvm->arch.use_irqchip = 0;
+	kvm->arch.use_vectors = 0;
 	kvm->arch.epoch = 0;
 
 	spin_lock_init(&kvm->arch.start_stop_lock);
@@ -1035,6 +1043,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 				    KVM_SYNC_CRS |
 				    KVM_SYNC_ARCH0 |
 				    KVM_SYNC_PFAULT;
+	if (test_kvm_facility(vcpu->kvm, 129))
+		vcpu->run->kvm_valid_regs |= KVM_SYNC_VRS;
 
 	if (kvm_is_ucontrol(vcpu->kvm))
 		return __kvm_ucontrol_vcpu_init(vcpu);
@@ -1045,10 +1055,18 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 {
 	save_fp_ctl(&vcpu->arch.host_fpregs.fpc);
-	save_fp_regs(vcpu->arch.host_fpregs.fprs);
+	if (vcpu->kvm->arch.use_vectors)
+		save_vx_regs((__vector128 *)&vcpu->arch.host_vregs->vrs);
+	else
+		save_fp_regs(vcpu->arch.host_fpregs.fprs);
 	save_access_regs(vcpu->arch.host_acrs);
-	restore_fp_ctl(&vcpu->arch.guest_fpregs.fpc);
-	restore_fp_regs(vcpu->arch.guest_fpregs.fprs);
+	if (vcpu->kvm->arch.use_vectors) {
+		restore_fp_ctl(&vcpu->run->s.regs.fpc);
+		restore_vx_regs((__vector128 *)&vcpu->run->s.regs.vrs);
+	} else {
+		restore_fp_ctl(&vcpu->arch.guest_fpregs.fpc);
+		restore_fp_regs(vcpu->arch.guest_fpregs.fprs);
+	}
 	restore_access_regs(vcpu->run->s.regs.acrs);
 	gmap_enable(vcpu->arch.gmap);
 	atomic_set_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
@@ -1058,11 +1076,19 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 {
 	atomic_clear_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
 	gmap_disable(vcpu->arch.gmap);
-	save_fp_ctl(&vcpu->arch.guest_fpregs.fpc);
-	save_fp_regs(vcpu->arch.guest_fpregs.fprs);
+	if (vcpu->kvm->arch.use_vectors) {
+		save_fp_ctl(&vcpu->run->s.regs.fpc);
+		save_vx_regs((__vector128 *)&vcpu->run->s.regs.vrs);
+	} else {
+		save_fp_ctl(&vcpu->arch.guest_fpregs.fpc);
+		save_fp_regs(vcpu->arch.guest_fpregs.fprs);
+	}
 	save_access_regs(vcpu->run->s.regs.acrs);
 	restore_fp_ctl(&vcpu->arch.host_fpregs.fpc);
-	restore_fp_regs(vcpu->arch.host_fpregs.fprs);
+	if (vcpu->kvm->arch.use_vectors)
+		restore_vx_regs((__vector128 *)&vcpu->arch.host_vregs->vrs);
+	else
+		restore_fp_regs(vcpu->arch.host_fpregs.fprs);
 	restore_access_regs(vcpu->arch.host_acrs);
 }
 
@@ -1196,6 +1222,7 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
 
 	vcpu->arch.sie_block = &sie_page->sie_block;
 	vcpu->arch.sie_block->itdba = (unsigned long) &sie_page->itdb;
+	vcpu->arch.host_vregs = &sie_page->vregs;
 
 	vcpu->arch.sie_block->icpua = id;
 	if (!kvm_is_ucontrol(kvm)) {