KVM: PPC: Book3S HV: Handle guest using doorbells for IPIs

* SRR1 wake reason field for system reset interrupt on wakeup from nap
  is now a 4-bit field on P8, compared to 3 bits on P7.

* Set PECEDP in LPCR when napping because of H_CEDE so guest doorbells
  will wake us up.

* Waking up from nap because of a guest doorbell interrupt is not a
  reason to exit the guest.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

arch/powerpc/include/asm/reg.h

@@ -307,7 +307,9 @@
 #define   LPCR_ILE     0x02000000      /* !HV irqs set MSR:LE */
 #define   LPCR_AIL_0	0x00000000	/* MMU off exception offset 0x0 */
 #define   LPCR_AIL_3	0x01800000	/* MMU on exception offset 0xc00...4xxx */
-#define   LPCR_PECE	0x00007000	/* powersave exit cause enable */
+#define   LPCR_PECE	0x0001f000	/* powersave exit cause enable */
+#define     LPCR_PECEDP	0x00010000	/* directed priv dbells cause exit */
+#define     LPCR_PECEDH	0x00008000	/* directed hyp dbells cause exit */
 #define     LPCR_PECE0	0x00004000	/* ext. exceptions can cause exit */
 #define     LPCR_PECE1	0x00002000	/* decrementer can cause exit */
 #define     LPCR_PECE2	0x00001000	/* machine check etc can cause exit */

arch/powerpc/kvm/book3s_hv_rmhandlers.S

@@ -1857,13 +1857,16 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_206)
 	bl	kvmppc_save_fp
 
 	/*
-	 * Take a nap until a decrementer or external interrupt occurs,
-	 * with PECE1 (wake on decr) and PECE0 (wake on external) set in LPCR
+	 * Take a nap until a decrementer or external or doobell interrupt
+	 * occurs, with PECE1, PECE0 and PECEDP set in LPCR
 	 */
 	li	r0,1
 	stb	r0,HSTATE_HWTHREAD_REQ(r13)
 	mfspr	r5,SPRN_LPCR
 	ori	r5,r5,LPCR_PECE0 | LPCR_PECE1
+BEGIN_FTR_SECTION
+	oris	r5,r5,LPCR_PECEDP@h
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
 	mtspr	SPRN_LPCR,r5
 	isync
 	li	r0, 0
@@ -1979,14 +1982,22 @@ machine_check_realmode:
  */
 kvmppc_check_wake_reason:
 	mfspr	r6, SPRN_SRR1
-	rlwinm	r6, r6, 44-31, 0x7	/* extract wake reason field */
-	cmpwi	r6, 4			/* was it an external interrupt? */
+BEGIN_FTR_SECTION
+	rlwinm	r6, r6, 45-31, 0xf	/* extract wake reason field (P8) */
+FTR_SECTION_ELSE
+	rlwinm	r6, r6, 45-31, 0xe	/* P7 wake reason field is 3 bits */
+ALT_FTR_SECTION_END_IFSET(CPU_FTR_ARCH_207S)
+	cmpwi	r6, 8			/* was it an external interrupt? */
 	li	r12, BOOK3S_INTERRUPT_EXTERNAL
 	beq	kvmppc_read_intr	/* if so, see what it was */
 	li	r3, 0
 	li	r12, 0
 	cmpwi	r6, 6			/* was it the decrementer? */
 	beq	0f
+BEGIN_FTR_SECTION
+	cmpwi	r6, 5			/* privileged doorbell? */
+	beq	0f
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
 	li	r3, 1			/* anything else, return 1 */
 0:	blr