[PATCH 18/26] KVM: PPC: Book3S PR: make mtspr/mfspr emulation behavior based on active TM SPRs

[wei.guo.simon at gmail.com]

From: Simon Guo <wei.guo.simon at gmail.com>

The mfspr/mtspr on TM SPRs(TEXASR/TFIAR/TFHAR) are non-privileged
instructions and can be executed at PR KVM guest without trapping
into host in problem state. We only emulate mtspr/mfspr
texasr/tfiar/tfhar at guest PR=0 state.

When we are emulating mtspr tm sprs at guest PR=0 state, the emulation
result need to be visible to guest PR=1 state. That is, the actual TM
SPR val should be loaded into actual registers.

We already flush TM SPRs into vcpu when switching out of CPU, and load
TM SPRs when switching back.

This patch corrects mfspr()/mtspr() emulation for TM SPRs to make the
actual source/dest based on actual TM SPRs.

Signed-off-by: Simon Guo <wei.guo.simon at gmail.com>
---
 arch/powerpc/kvm/book3s_emulate.c | 35 +++++++++++++++++++++++++++--------
 1 file changed, 27 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_emulate.c b/arch/powerpc/kvm/book3s_emulate.c
index e096d01..c2836330 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c
@@ -521,13 +521,26 @@ int kvmppc_core_emulate_mtspr_pr(struct kvm_vcpu *vcpu, int sprn, ulong spr_val)
 		break;
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 	case SPRN_TFHAR:
-		vcpu->arch.tfhar = spr_val;
-		break;
 	case SPRN_TEXASR:
-		vcpu->arch.texasr = spr_val;
-		break;
 	case SPRN_TFIAR:
-		vcpu->arch.tfiar = spr_val;
+		if (MSR_TM_ACTIVE(kvmppc_get_msr(vcpu))) {
+			/* it is illegal to mtspr() TM regs in
+			 * other than non-transactional state.
+			 */
+			kvmppc_core_queue_program(vcpu, SRR1_PROGTM);
+			emulated = EMULATE_AGAIN;
+			break;
+		}
+
+		tm_enable();
+		if (sprn == SPRN_TFHAR)
+			mtspr(SPRN_TFHAR, spr_val);
+		else if (sprn == SPRN_TEXASR)
+			mtspr(SPRN_TEXASR, spr_val);
+		else
+			mtspr(SPRN_TFIAR, spr_val);
+		tm_disable();
+
 		break;
 #endif
 #endif
@@ -674,13 +687,19 @@ int kvmppc_core_emulate_mfspr_pr(struct kvm_vcpu *vcpu, int sprn, ulong *spr_val
 		break;
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 	case SPRN_TFHAR:
-		*spr_val = vcpu->arch.tfhar;
+		tm_enable();
+		*spr_val = mfspr(SPRN_TFHAR);
+		tm_disable();
 		break;
 	case SPRN_TEXASR:
-		*spr_val = vcpu->arch.texasr;
+		tm_enable();
+		*spr_val = mfspr(SPRN_TEXASR);
+		tm_disable();
 		break;
 	case SPRN_TFIAR:
-		*spr_val = vcpu->arch.tfiar;
+		tm_enable();
+		*spr_val = mfspr(SPRN_TFIAR);
+		tm_disable();
 		break;
 #endif
 #endif
-- 
1.8.3.1