KVM: PPC: Book3S HV: Don't use ASDR for real-mode HPT faults on POWER9

paulusmack · paulusmack · commit 4e5acdc23a3d · 2017-03-01T11:54:10.000+11:00
In HPT mode on POWER9, the ASDR register is supposed to record
segment information for hypervisor page faults.  It turns out that
POWER9 DD1 does not record the page size information in the ASDR
for faults in guest real mode.  We have the necessary information
in memory already, so by moving the checks for real mode that already
existed, we can use the in-memory copy.  Since a load is likely to
be faster than reading an SPR, we do this unconditionally (not just
for POWER9 DD1).

Signed-off-by: Paul Mackerras &lt;paulus@ozlabs.org&gt;
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -1787,12 +1787,12 @@ kvmppc_hdsi:
 	/* HPTE not found fault or protection fault? */
 	andis.	r0, r6, (DSISR_NOHPTE | DSISR_PROTFAULT)@h
 	beq	1f			/* if not, send it to the guest */
+	andi.	r0, r11, MSR_DR		/* data relocation enabled? */
+	beq	3f
 BEGIN_FTR_SECTION
 	mfspr	r5, SPRN_ASDR		/* on POWER9, use ASDR to get VSID */
 	b	4f
 END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
-	andi.	r0, r11, MSR_DR		/* data relocation enabled? */
-	beq	3f
 	clrrdi	r0, r4, 28
 	PPC_SLBFEE_DOT(R5, R0)		/* if so, look up SLB */
 	li	r0, BOOK3S_INTERRUPT_DATA_SEGMENT
@@ -1879,12 +1879,12 @@ kvmppc_hisi:
 	bne	.Lradix_hisi		/* for radix, just save ASDR */
 	andis.	r0, r11, SRR1_ISI_NOPT@h
 	beq	1f
+	andi.	r0, r11, MSR_IR		/* instruction relocation enabled? */
+	beq	3f
 BEGIN_FTR_SECTION
 	mfspr	r5, SPRN_ASDR		/* on POWER9, use ASDR to get VSID */
 	b	4f
 END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
-	andi.	r0, r11, MSR_IR		/* instruction relocation enabled? */
-	beq	3f
 	clrrdi	r0, r10, 28
 	PPC_SLBFEE_DOT(R5, R0)		/* if so, look up SLB */
 	li	r0, BOOK3S_INTERRUPT_INST_SEGMENT
