KVM: PPC: Book3S PR: Emulate mtspr/mfspr using active TM SPRs

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

When we are emulating mtspr tm sprs in guest PR=0 state, the emulation
result needs 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 be the actual TM SPRs.

Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

arch/powerpc/include/asm/kvm_book3s.h

@@ -210,6 +210,7 @@ extern void kvmppc_book3s_queue_irqprio(struct kvm_vcpu *vcpu, unsigned int vec)
 extern void kvmppc_book3s_dequeue_irqprio(struct kvm_vcpu *vcpu,
 					  unsigned int vec);
 extern void kvmppc_inject_interrupt(struct kvm_vcpu *vcpu, int vec, u64 flags);
+extern void kvmppc_trigger_fac_interrupt(struct kvm_vcpu *vcpu, ulong fac);
 extern void kvmppc_set_bat(struct kvm_vcpu *vcpu, struct kvmppc_bat *bat,
 			   bool upper, u32 val);
 extern void kvmppc_giveup_ext(struct kvm_vcpu *vcpu, ulong msr);

arch/powerpc/kvm/book3s_emulate.c

@@ -24,6 +24,7 @@
 #include <asm/switch_to.h>
 #include <asm/time.h>
 #include "book3s.h"
+#include <asm/asm-prototypes.h>
 
 #define OP_19_XOP_RFID		18
 #define OP_19_XOP_RFI		50
@@ -523,13 +524,38 @@ 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 (!cpu_has_feature(CPU_FTR_TM))
+			break;
+
+		if (!(kvmppc_get_msr(vcpu) & MSR_TM)) {
+			kvmppc_trigger_fac_interrupt(vcpu, FSCR_TM_LG);
+			emulated = EMULATE_AGAIN;
+			break;
+		}
+
+		if (MSR_TM_ACTIVE(kvmppc_get_msr(vcpu)) &&
+			!((MSR_TM_SUSPENDED(kvmppc_get_msr(vcpu))) &&
+					(sprn == SPRN_TFHAR))) {
+			/* it is illegal to mtspr() TM regs in
+			 * other than non-transactional state, with
+			 * the exception of TFHAR in suspend 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
@@ -676,13 +702,25 @@ 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;
-		break;
 	case SPRN_TEXASR:
-		*spr_val = vcpu->arch.texasr;
-		break;
 	case SPRN_TFIAR:
-		*spr_val = vcpu->arch.tfiar;
+		if (!cpu_has_feature(CPU_FTR_TM))
+			break;
+
+		if (!(kvmppc_get_msr(vcpu) & MSR_TM)) {
+			kvmppc_trigger_fac_interrupt(vcpu, FSCR_TM_LG);
+			emulated = EMULATE_AGAIN;
+			break;
+		}
+
+		tm_enable();
+		if (sprn == SPRN_TFHAR)
+			*spr_val = mfspr(SPRN_TFHAR);
+		else if (sprn == SPRN_TEXASR)
+			*spr_val = mfspr(SPRN_TEXASR);
+		else if (sprn == SPRN_TFIAR)
+			*spr_val = mfspr(SPRN_TFIAR);
+		tm_disable();
 		break;
 #endif
 #endif

arch/powerpc/kvm/book3s_pr.c

@@ -918,7 +918,7 @@ static void kvmppc_handle_lost_ext(struct kvm_vcpu *vcpu)
 
 #ifdef CONFIG_PPC_BOOK3S_64
 
-static void kvmppc_trigger_fac_interrupt(struct kvm_vcpu *vcpu, ulong fac)
+void kvmppc_trigger_fac_interrupt(struct kvm_vcpu *vcpu, ulong fac)
 {
 	/* Inject the Interrupt Cause field and trigger a guest interrupt */
 	vcpu->arch.fscr &= ~(0xffULL << 56);