KVM: PPC: Implement MMU notifiers for Book3S HV guests

This adds the infrastructure to enable us to page out pages underneath
a Book3S HV guest, on processors that support virtualized partition
memory, that is, POWER7.  Instead of pinning all the guest's pages,
we now look in the host userspace Linux page tables to find the
mapping for a given guest page.  Then, if the userspace Linux PTE
gets invalidated, kvm_unmap_hva() gets called for that address, and
we replace all the guest HPTEs that refer to that page with absent
HPTEs, i.e. ones with the valid bit clear and the HPTE_V_ABSENT bit
set, which will cause an HDSI when the guest tries to access them.
Finally, the page fault handler is extended to reinstantiate the
guest HPTE when the guest tries to access a page which has been paged
out.

Since we can't intercept the guest DSI and ISI interrupts on PPC970,
we still have to pin all the guest pages on PPC970.  We have a new flag,
kvm->arch.using_mmu_notifiers, that indicates whether we can page
guest pages out.  If it is not set, the MMU notifier callbacks do
nothing and everything operates as before.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index d07b64d5f37e..7d4990665d00 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -621,6 +621,8 @@ BEGIN_FTR_SECTION
 	/* If this is a page table miss then see if it's theirs or ours */
 	cmpwi	r12, BOOK3S_INTERRUPT_H_DATA_STORAGE
 	beq	kvmppc_hdsi
+	cmpwi	r12, BOOK3S_INTERRUPT_H_INST_STORAGE
+	beq	kvmppc_hisi
 END_FTR_SECTION_IFSET(CPU_FTR_ARCH_206)
 
 	/* See if this is a leftover HDEC interrupt */
@@ -1125,6 +1127,7 @@ kvmppc_hdsi:
 
 	/* Search the hash table. */
 	mr	r3, r9			/* vcpu pointer */
+	li	r7, 1			/* data fault */
 	bl	.kvmppc_hpte_hv_fault
 	ld	r9, HSTATE_KVM_VCPU(r13)
 	ld	r10, VCPU_PC(r9)
@@ -1182,6 +1185,52 @@ kvmppc_hdsi:
 	b	nohpte_cont
 
 /*
+ * Similarly for an HISI, reflect it to the guest as an ISI unless
+ * it is an HPTE not found fault for a page that we have paged out.
+ */
+kvmppc_hisi:
+	andis.	r0, r11, SRR1_ISI_NOPT@h
+	beq	1f
+	andi.	r0, r11, MSR_IR		/* instruction relocation enabled? */
+	beq	3f
+	clrrdi	r0, r10, 28
+	PPC_SLBFEE_DOT(r5, r0)		/* if so, look up SLB */
+	bne	1f			/* if no SLB entry found */
+4:
+	/* Search the hash table. */
+	mr	r3, r9			/* vcpu pointer */
+	mr	r4, r10
+	mr	r6, r11
+	li	r7, 0			/* instruction fault */
+	bl	.kvmppc_hpte_hv_fault
+	ld	r9, HSTATE_KVM_VCPU(r13)
+	ld	r10, VCPU_PC(r9)
+	ld	r11, VCPU_MSR(r9)
+	li	r12, BOOK3S_INTERRUPT_H_INST_STORAGE
+	cmpdi	r3, 0			/* retry the instruction */
+	beq	6f
+	cmpdi	r3, -1			/* handle in kernel mode */
+	beq	nohpte_cont
+
+	/* Synthesize an ISI for the guest */
+	mr	r11, r3
+1:	mtspr	SPRN_SRR0, r10
+	mtspr	SPRN_SRR1, r11
+	li	r10, BOOK3S_INTERRUPT_INST_STORAGE
+	li	r11, (MSR_ME << 1) | 1	/* synthesize MSR_SF | MSR_ME */
+	rotldi	r11, r11, 63
+6:	ld	r7, VCPU_CTR(r9)
+	lwz	r8, VCPU_XER(r9)
+	mtctr	r7
+	mtxer	r8
+	mr	r4, r9
+	b	fast_guest_return
+
+3:	ld	r6, VCPU_KVM(r9)	/* not relocated, use VRMA */
+	ld	r5, KVM_VRMA_SLB_V(r6)
+	b	4b
+
+/*
  * Try to handle an hcall in real mode.
  * Returns to the guest if we handle it, or continues on up to
  * the kernel if we can't (i.e. if we don't have a handler for