KVM: PPC: Book3S PR: Fix failure status setting in tabort. emulation

tabort. will perform transaction failure recording and the recording
depends on TEXASR FS bit. Currently the TEXASR FS bit is retrieved
after tabort., when the TEXASR FS bit is already been updated by
tabort. itself.

This patch corrects this behavior by retrieving TEXASR val before
tabort.

tabort. will not immediately leads to transaction failure handling
in suspend state. So this patch also remove the mtspr on TEXASR/TFIAR
registers to avoid TM bad thing exception.

Fixes: 26798f88 ("KVM: PPC: Book3S PR: Add emulation for tabort. in privileged state")
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

arch/powerpc/kvm/book3s_emulate.c

@@ -212,9 +212,11 @@ void kvmppc_emulate_tabort(struct kvm_vcpu *vcpu, int ra_val)
 	 * present.
 	 */
 	unsigned long guest_msr = kvmppc_get_msr(vcpu);
+	uint64_t org_texasr;
 
 	preempt_disable();
 	tm_enable();
+	org_texasr = mfspr(SPRN_TEXASR);
 	tm_abort(ra_val);
 
 	/* CR0 = 0 | MSR[TS] | 0 */
@@ -227,7 +229,7 @@ void kvmppc_emulate_tabort(struct kvm_vcpu *vcpu, int ra_val)
 	 * and tabort will be treated as nops in non-transactional
 	 * state.
 	 */
-	if (!(vcpu->arch.texasr & TEXASR_FS) &&
+	if (!(org_texasr & TEXASR_FS) &&
 			MSR_TM_ACTIVE(guest_msr)) {
 		vcpu->arch.texasr &= ~(TEXASR_PR | TEXASR_HV);
 		if (guest_msr & MSR_PR)
@@ -237,8 +239,6 @@ void kvmppc_emulate_tabort(struct kvm_vcpu *vcpu, int ra_val)
 			vcpu->arch.texasr |= TEXASR_HV;
 
 		vcpu->arch.tfiar = kvmppc_get_pc(vcpu);
-		mtspr(SPRN_TEXASR, vcpu->arch.texasr);
-		mtspr(SPRN_TFIAR, vcpu->arch.tfiar);
 	}
 	tm_disable();
 	preempt_enable();