KVM: PPC: book3s_hv: Add support for PPC970-family processors

This adds support for running KVM guests in supervisor mode on those
PPC970 processors that have a usable hypervisor mode.  Unfortunately,
Apple G5 machines have supervisor mode disabled (MSR[HV] is forced to
1), but the YDL PowerStation does have a usable hypervisor mode.

There are several differences between the PPC970 and POWER7 in how
guests are managed.  These differences are accommodated using the
CPU_FTR_ARCH_201 (PPC970) and CPU_FTR_ARCH_206 (POWER7) CPU feature
bits.  Notably, on PPC970:

* The LPCR, LPID or RMOR registers don't exist, and the functions of
  those registers are provided by bits in HID4 and one bit in HID0.

* External interrupts can be directed to the hypervisor, but unlike
  POWER7 they are masked by MSR[EE] in non-hypervisor modes and use
  SRR0/1 not HSRR0/1.

* There is no virtual RMA (VRMA) mode; the guest must use an RMO
  (real mode offset) area.

* The TLB entries are not tagged with the LPID, so it is necessary to
  flush the whole TLB on partition switch.  Furthermore, when switching
  partitions we have to ensure that no other CPU is executing the tlbie
  or tlbsync instructions in either the old or the new partition,
  otherwise undefined behaviour can occur.

* The PMU has 8 counters (PMC registers) rather than 6.

* The DSCR, PURR, SPURR, AMR, AMOR, UAMOR registers don't exist.

* The SLB has 64 entries rather than 32.

* There is no mediated external interrupt facility, so if we switch to
  a guest that has a virtual external interrupt pending but the guest
  has MSR[EE] = 0, we have to arrange to have an interrupt pending for
  it so that we can get control back once it re-enables interrupts.  We
  do that by sending ourselves an IPI with smp_send_reschedule after
  hard-disabling interrupts.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

arch/powerpc/kvm/book3s_hv_interrupts.S

@@ -50,8 +50,10 @@ _GLOBAL(__kvmppc_vcore_entry)
 	SAVE_NVGPRS(r1)
 
 	/* Save host DSCR */
+BEGIN_FTR_SECTION
 	mfspr	r3, SPRN_DSCR
 	std	r3, HSTATE_DSCR(r13)
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_206)
 
 	/* Save host DABR */
 	mfspr	r3, SPRN_DABR
@@ -86,12 +88,20 @@ _GLOBAL(__kvmppc_vcore_entry)
 	mfspr	r7, SPRN_PMC4
 	mfspr	r8, SPRN_PMC5
 	mfspr	r9, SPRN_PMC6
+BEGIN_FTR_SECTION
+	mfspr	r10, SPRN_PMC7
+	mfspr	r11, SPRN_PMC8
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_201)
 	stw	r3, HSTATE_PMC(r13)
 	stw	r5, HSTATE_PMC + 4(r13)
 	stw	r6, HSTATE_PMC + 8(r13)
 	stw	r7, HSTATE_PMC + 12(r13)
 	stw	r8, HSTATE_PMC + 16(r13)
 	stw	r9, HSTATE_PMC + 20(r13)
+BEGIN_FTR_SECTION
+	stw	r10, HSTATE_PMC + 24(r13)
+	stw	r11, HSTATE_PMC + 28(r13)
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_201)
 31:
 
 	/*
@@ -105,6 +115,26 @@ _GLOBAL(__kvmppc_vcore_entry)
 	add	r8,r8,r7
 	std	r8,HSTATE_DECEXP(r13)
 
+	/*
+	 * On PPC970, if the guest vcpu has an external interrupt pending,
+	 * send ourselves an IPI so as to interrupt the guest once it
+	 * enables interrupts.  (It must have interrupts disabled,
+	 * otherwise we would already have delivered the interrupt.)
+	 */
+BEGIN_FTR_SECTION
+	ld	r0, VCPU_PENDING_EXC(r4)
+	li	r7, (1 << BOOK3S_IRQPRIO_EXTERNAL)
+	oris	r7, r7, (1 << BOOK3S_IRQPRIO_EXTERNAL_LEVEL)@h
+	and.	r0, r0, r7
+	beq	32f
+	mr	r31, r4
+	lhz	r3, PACAPACAINDEX(r13)
+	bl	smp_send_reschedule
+	nop
+	mr	r4, r31
+32:
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_201)
+
 	/* Jump to partition switch code */
 	bl	.kvmppc_hv_entry_trampoline
 	nop