KVM: PPC: Book3S HV: Add H_SET_MODE hcall handling

This adds support for the H_SET_MODE hcall.  This hcall is a
multiplexer that has several functions, some of which are called
rarely, and some which are potentially called very frequently.
Here we add support for the functions that set the debug registers
CIABR (Completed Instruction Address Breakpoint Register) and
DAWR/DAWRX (Data Address Watchpoint Register and eXtension),
since they could be updated by the guest as often as every context
switch.

This also adds a kvmppc_power8_compatible() function to test to see
if a guest is compatible with POWER8 or not.  The CIABR and DAWR/X
only exist on POWER8.

Signed-off-by: Michael Neuling <[email protected]>
Signed-off-by: Paul Mackerras <[email protected]>
Signed-off-by: Alexander Graf <[email protected]>

arch/powerpc/include/asm/hvcall.h

@@ -279,6 +279,12 @@
 #define H_GET_24X7_DATA		0xF07C
 #define H_GET_PERF_COUNTER_INFO	0xF080
 
+/* Values for 2nd argument to H_SET_MODE */
+#define H_SET_MODE_RESOURCE_SET_CIABR		1
+#define H_SET_MODE_RESOURCE_SET_DAWR		2
+#define H_SET_MODE_RESOURCE_ADDR_TRANS_MODE	3
+#define H_SET_MODE_RESOURCE_LE			4
+
 #ifndef __ASSEMBLY__
 
 /**

arch/powerpc/kvm/book3s_hv.c

@@ -557,6 +557,48 @@ static void kvmppc_create_dtl_entry(struct kvm_vcpu *vcpu,
 	vcpu->arch.dtl.dirty = true;
 }
 
+static bool kvmppc_power8_compatible(struct kvm_vcpu *vcpu)
+{
+	if (vcpu->arch.vcore->arch_compat >= PVR_ARCH_207)
+		return true;
+	if ((!vcpu->arch.vcore->arch_compat) &&
+	    cpu_has_feature(CPU_FTR_ARCH_207S))
+		return true;
+	return false;
+}
+
+static int kvmppc_h_set_mode(struct kvm_vcpu *vcpu, unsigned long mflags,
+			     unsigned long resource, unsigned long value1,
+			     unsigned long value2)
+{
+	switch (resource) {
+	case H_SET_MODE_RESOURCE_SET_CIABR:
+		if (!kvmppc_power8_compatible(vcpu))
+			return H_P2;
+		if (value2)
+			return H_P4;
+		if (mflags)
+			return H_UNSUPPORTED_FLAG_START;
+		/* Guests can't breakpoint the hypervisor */
+		if ((value1 & CIABR_PRIV) == CIABR_PRIV_HYPER)
+			return H_P3;
+		vcpu->arch.ciabr  = value1;
+		return H_SUCCESS;
+	case H_SET_MODE_RESOURCE_SET_DAWR:
+		if (!kvmppc_power8_compatible(vcpu))
+			return H_P2;
+		if (mflags)
+			return H_UNSUPPORTED_FLAG_START;
+		if (value2 & DABRX_HYP)
+			return H_P4;
+		vcpu->arch.dawr  = value1;
+		vcpu->arch.dawrx = value2;
+		return H_SUCCESS;
+	default:
+		return H_TOO_HARD;
+	}
+}
+
 int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
 {
 	unsigned long req = kvmppc_get_gpr(vcpu, 3);
@@ -626,7 +668,14 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
 
 		/* Send the error out to userspace via KVM_RUN */
 		return rc;
-
+	case H_SET_MODE:
+		ret = kvmppc_h_set_mode(vcpu, kvmppc_get_gpr(vcpu, 4),
+					kvmppc_get_gpr(vcpu, 5),
+					kvmppc_get_gpr(vcpu, 6),
+					kvmppc_get_gpr(vcpu, 7));
+		if (ret == H_TOO_HARD)
+			return RESUME_HOST;
+		break;
 	case H_XIRR:
 	case H_CPPR:
 	case H_EOI:
@@ -652,6 +701,7 @@ static int kvmppc_hcall_impl_hv(unsigned long cmd)
 	case H_PROD:
 	case H_CONFER:
 	case H_REGISTER_VPA:
+	case H_SET_MODE:
 #ifdef CONFIG_KVM_XICS
 	case H_XIRR:
 	case H_CPPR: