KVM: powerpc: Fix mtsrin in book3s_64 mmu

We were shifting the Ks/Kp/N bits one bit too far on mtsrin. It took
me some time to figure that out, so I also put in some debugging and a
comment explaining the conversion.

This fixes current OpenBIOS boot on PPC64 KVM.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

arch/powerpc/kvm/book3s_64_mmu.c

@@ -390,6 +390,26 @@ static void kvmppc_mmu_book3s_64_mtsrin(struct kvm_vcpu *vcpu, u32 srnum,
 {
 	u64 rb = 0, rs = 0;
 
+	/*
+	 * According to Book3 2.01 mtsrin is implemented as:
+	 *
+	 * The SLB entry specified by (RB)32:35 is loaded from register
+	 * RS, as follows.
+	 *
+	 * SLBE Bit	Source			SLB Field
+	 *
+	 * 0:31		0x0000_0000		ESID-0:31
+	 * 32:35	(RB)32:35		ESID-32:35
+	 * 36		0b1			V
+	 * 37:61	0x00_0000|| 0b0		VSID-0:24
+	 * 62:88	(RS)37:63		VSID-25:51
+	 * 89:91	(RS)33:35		Ks Kp N
+	 * 92		(RS)36			L ((RS)36 must be 0b0)
+	 * 93		0b0			C
+	 */
+
+	dprintk("KVM MMU: mtsrin(0x%x, 0x%lx)\n", srnum, value);
+
 	/* ESID = srnum */
 	rb |= (srnum & 0xf) << 28;
 	/* Set the valid bit */
@@ -400,7 +420,7 @@ static void kvmppc_mmu_book3s_64_mtsrin(struct kvm_vcpu *vcpu, u32 srnum,
 	/* VSID = VSID */
 	rs |= (value & 0xfffffff) << 12;
 	/* flags = flags */
-	rs |= ((value >> 27) & 0xf) << 9;
+	rs |= ((value >> 28) & 0x7) << 9;
 
 	kvmppc_mmu_book3s_64_slbmte(vcpu, rs, rb);
 }