KVM: PPC: Added one_reg interface for timer registers

If userspace wants to change some specific bits of TSR
(timer status register) then it uses GET/SET_SREGS ioctl interface.
So the steps will be:
      i)   user-space will make get ioctl,
      ii)  change TSR in userspace
      iii) then make set ioctl.
It can happen that TSR gets changed by kernel after step i) and
before step iii).

To avoid this we have added below one_reg ioctls for oring and clearing
specific bits in TSR. This patch adds one registerface for:
     1) setting specific bit in TSR (timer status register)
     2) clearing specific bit in TSR (timer status register)
     3) setting/getting the TCR register. There are cases where we want to only
        change TCR and not TSR. Although we can uses SREGS without
        KVM_SREGS_E_UPDATE_TSR flag but I think one reg is better. I am open
        if someone feels we should use SREGS only here.
     4) getting/setting TSR register

Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

3 files changed, 39 insertions, 0 deletions

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index c16b442556e8..976eb650e7ef 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1788,6 +1788,10 @@ registers, find a list below:
   PPC   | KVM_REG_PPC_VPA_DTL   | 128
   PPC   | KVM_REG_PPC_EPCR	| 32
   PPC   | KVM_REG_PPC_EPR	| 32
+  PPC   | KVM_REG_PPC_TCR	| 32
+  PPC   | KVM_REG_PPC_TSR	| 32
+  PPC   | KVM_REG_PPC_OR_TSR	| 32
+  PPC   | KVM_REG_PPC_CLEAR_TSR	| 32
 
 ARM registers are mapped using the lower 32 bits.  The upper 16 of that
 is the register group type, or coprocessor number:
diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
index 16064d00adb9..ef072b1a6e3f 100644
--- a/arch/powerpc/include/uapi/asm/kvm.h
+++ b/arch/powerpc/include/uapi/asm/kvm.h
@@ -417,4 +417,9 @@ struct kvm_get_htab_header {
 #define KVM_REG_PPC_EPCR	(KVM_REG_PPC | KVM_REG_SIZE_U32 | 0x85)
 #define KVM_REG_PPC_EPR		(KVM_REG_PPC | KVM_REG_SIZE_U32 | 0x86)
 
+/* Timer Status Register OR/CLEAR interface */
+#define KVM_REG_PPC_OR_TSR	(KVM_REG_PPC | KVM_REG_SIZE_U32 | 0x87)
+#define KVM_REG_PPC_CLEAR_TSR	(KVM_REG_PPC | KVM_REG_SIZE_U32 | 0x88)
+#define KVM_REG_PPC_TCR		(KVM_REG_PPC | KVM_REG_SIZE_U32 | 0x89)
+#define KVM_REG_PPC_TSR		(KVM_REG_PPC | KVM_REG_SIZE_U32 | 0x8a)
 #endif /* __LINUX_KVM_POWERPC_H */
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index f2fd47d35ab5..11825539e2b1 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -1442,6 +1442,12 @@ int kvm_vcpu_ioctl_get_one_reg(struct kvm_vcpu *vcpu, struct kvm_one_reg *reg)
 		r = put_user(vcpu->arch.epcr, (u32 __user *)(long)reg->addr);
 		break;
 #endif
+	case KVM_REG_PPC_TCR:
+		r = put_user(vcpu->arch.tcr, (u32 __user *)(long)reg->addr);
+		break;
+	case KVM_REG_PPC_TSR:
+		r = put_user(vcpu->arch.tsr, (u32 __user *)(long)reg->addr);
+		break;
 	default:
 		break;
 	}
@@ -1485,6 +1491,30 @@ int kvm_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu, struct kvm_one_reg *reg)
 		break;
 	}
 #endif
+	case KVM_REG_PPC_OR_TSR: {
+		u32 tsr_bits;
+		r = get_user(tsr_bits, (u32 __user *)(long)reg->addr);
+		kvmppc_set_tsr_bits(vcpu, tsr_bits);
+		break;
+	}
+	case KVM_REG_PPC_CLEAR_TSR: {
+		u32 tsr_bits;
+		r = get_user(tsr_bits, (u32 __user *)(long)reg->addr);
+		kvmppc_clr_tsr_bits(vcpu, tsr_bits);
+		break;
+	}
+	case KVM_REG_PPC_TSR: {
+		u32 tsr;
+		r = get_user(tsr, (u32 __user *)(long)reg->addr);
+		kvmppc_set_tsr(vcpu, tsr);
+		break;
+	}
+	case KVM_REG_PPC_TCR: {
+		u32 tcr;
+		r = get_user(tcr, (u32 __user *)(long)reg->addr);
+		kvmppc_set_tcr(vcpu, tcr);
+		break;
+	}
 	default:
 		break;
 	}