1 files changed, 356 insertions, 107 deletions

diff --git a/arch/powerpc/kvm/44x_tlb.c b/arch/powerpc/kvm/44x_tlb.c
index ad72c6f9811f..9a34b8edb9e2 100644
--- a/arch/powerpc/kvm/44x_tlb.c
+++ b/arch/powerpc/kvm/44x_tlb.c
@@ -22,20 +22,103 @@
 #include <linux/kvm.h>
 #include <linux/kvm_host.h>
 #include <linux/highmem.h>
+
+#include <asm/tlbflush.h>
 #include <asm/mmu-44x.h>
 #include <asm/kvm_ppc.h>
+#include <asm/kvm_44x.h>
+#include "timing.h"
 
 #include "44x_tlb.h"
 
+#ifndef PPC44x_TLBE_SIZE
+#define PPC44x_TLBE_SIZE	PPC44x_TLB_4K
+#endif
+
+#define PAGE_SIZE_4K (1<<12)
+#define PAGE_MASK_4K (~(PAGE_SIZE_4K - 1))
+
+#define PPC44x_TLB_UATTR_MASK \
+	(PPC44x_TLB_U0|PPC44x_TLB_U1|PPC44x_TLB_U2|PPC44x_TLB_U3)
 #define PPC44x_TLB_USER_PERM_MASK (PPC44x_TLB_UX|PPC44x_TLB_UR|PPC44x_TLB_UW)
 #define PPC44x_TLB_SUPER_PERM_MASK (PPC44x_TLB_SX|PPC44x_TLB_SR|PPC44x_TLB_SW)
 
-static unsigned int kvmppc_tlb_44x_pos;
+#ifdef DEBUG
+void kvmppc_dump_tlbs(struct kvm_vcpu *vcpu)
+{
+	struct kvmppc_44x_tlbe *tlbe;
+	int i;
+
+	printk("vcpu %d TLB dump:\n", vcpu->vcpu_id);
+	printk("| %2s | %3s | %8s | %8s | %8s |\n",
+			"nr", "tid", "word0", "word1", "word2");
+
+	for (i = 0; i < ARRAY_SIZE(vcpu_44x->guest_tlb); i++) {
+		tlbe = &vcpu_44x->guest_tlb[i];
+		if (tlbe->word0 & PPC44x_TLB_VALID)
+			printk(" G%2d |  %02X | %08X | %08X | %08X |\n",
+			       i, tlbe->tid, tlbe->word0, tlbe->word1,
+			       tlbe->word2);
+	}
+}
+#endif
+
+static inline void kvmppc_44x_tlbie(unsigned int index)
+{
+	/* 0 <= index < 64, so the V bit is clear and we can use the index as
+	 * word0. */
+	asm volatile(
+		"tlbwe %[index], %[index], 0\n"
+	:
+	: [index] "r"(index)
+	);
+}
+
+static inline void kvmppc_44x_tlbre(unsigned int index,
+                                    struct kvmppc_44x_tlbe *tlbe)
+{
+	asm volatile(
+		"tlbre %[word0], %[index], 0\n"
+		"mfspr %[tid], %[sprn_mmucr]\n"
+		"andi. %[tid], %[tid], 0xff\n"
+		"tlbre %[word1], %[index], 1\n"
+		"tlbre %[word2], %[index], 2\n"
+		: [word0] "=r"(tlbe->word0),
+		  [word1] "=r"(tlbe->word1),
+		  [word2] "=r"(tlbe->word2),
+		  [tid]   "=r"(tlbe->tid)
+		: [index] "r"(index),
+		  [sprn_mmucr] "i"(SPRN_MMUCR)
+		: "cc"
+	);
+}
+
+static inline void kvmppc_44x_tlbwe(unsigned int index,
+                                    struct kvmppc_44x_tlbe *stlbe)
+{
+	unsigned long tmp;
+
+	asm volatile(
+		"mfspr %[tmp], %[sprn_mmucr]\n"
+		"rlwimi %[tmp], %[tid], 0, 0xff\n"
+		"mtspr %[sprn_mmucr], %[tmp]\n"
+		"tlbwe %[word0], %[index], 0\n"
+		"tlbwe %[word1], %[index], 1\n"
+		"tlbwe %[word2], %[index], 2\n"
+		: [tmp]   "=&r"(tmp)
+		: [word0] "r"(stlbe->word0),
+		  [word1] "r"(stlbe->word1),
+		  [word2] "r"(stlbe->word2),
+		  [tid]   "r"(stlbe->tid),
+		  [index] "r"(index),
+		  [sprn_mmucr] "i"(SPRN_MMUCR)
+	);
+}
 
 static u32 kvmppc_44x_tlb_shadow_attrib(u32 attrib, int usermode)
 {
-	/* Mask off reserved bits. */
-	attrib &= PPC44x_TLB_PERM_MASK|PPC44x_TLB_ATTR_MASK;
+	/* We only care about the guest's permission and user bits. */
+	attrib &= PPC44x_TLB_PERM_MASK|PPC44x_TLB_UATTR_MASK;
 
 	if (!usermode) {
 		/* Guest is in supervisor mode, so we need to translate guest
@@ -47,18 +130,60 @@ static u32 kvmppc_44x_tlb_shadow_attrib(u32 attrib, int usermode)
 	/* Make sure host can always access this memory. */
 	attrib |= PPC44x_TLB_SX|PPC44x_TLB_SR|PPC44x_TLB_SW;
 
+	/* WIMGE = 0b00100 */
+	attrib |= PPC44x_TLB_M;
+
 	return attrib;
 }
 
+/* Load shadow TLB back into hardware. */
+void kvmppc_44x_tlb_load(struct kvm_vcpu *vcpu)
+{
+	struct kvmppc_vcpu_44x *vcpu_44x = to_44x(vcpu);
+	int i;
+
+	for (i = 0; i <= tlb_44x_hwater; i++) {
+		struct kvmppc_44x_tlbe *stlbe = &vcpu_44x->shadow_tlb[i];
+
+		if (get_tlb_v(stlbe) && get_tlb_ts(stlbe))
+			kvmppc_44x_tlbwe(i, stlbe);
+	}
+}
+
+static void kvmppc_44x_tlbe_set_modified(struct kvmppc_vcpu_44x *vcpu_44x,
+                                         unsigned int i)
+{
+	vcpu_44x->shadow_tlb_mod[i] = 1;
+}
+
+/* Save hardware TLB to the vcpu, and invalidate all guest mappings. */
+void kvmppc_44x_tlb_put(struct kvm_vcpu *vcpu)
+{
+	struct kvmppc_vcpu_44x *vcpu_44x = to_44x(vcpu);
+	int i;
+
+	for (i = 0; i <= tlb_44x_hwater; i++) {
+		struct kvmppc_44x_tlbe *stlbe = &vcpu_44x->shadow_tlb[i];
+
+		if (vcpu_44x->shadow_tlb_mod[i])
+			kvmppc_44x_tlbre(i, stlbe);
+
+		if (get_tlb_v(stlbe) && get_tlb_ts(stlbe))
+			kvmppc_44x_tlbie(i);
+	}
+}
+
+
 /* Search the guest TLB for a matching entry. */
 int kvmppc_44x_tlb_index(struct kvm_vcpu *vcpu, gva_t eaddr, unsigned int pid,
                          unsigned int as)
 {
+	struct kvmppc_vcpu_44x *vcpu_44x = to_44x(vcpu);
 	int i;
 
 	/* XXX Replace loop with fancy data structures. */
-	for (i = 0; i < PPC44x_TLB_SIZE; i++) {
-		struct tlbe *tlbe = &vcpu->arch.guest_tlb[i];
+	for (i = 0; i < ARRAY_SIZE(vcpu_44x->guest_tlb); i++) {
+		struct kvmppc_44x_tlbe *tlbe = &vcpu_44x->guest_tlb[i];
 		unsigned int tid;
 
 		if (eaddr < get_tlb_eaddr(tlbe))
@@ -83,78 +208,89 @@ int kvmppc_44x_tlb_index(struct kvm_vcpu *vcpu, gva_t eaddr, unsigned int pid,
 	return -1;
 }
 
-struct tlbe *kvmppc_44x_itlb_search(struct kvm_vcpu *vcpu, gva_t eaddr)
+int kvmppc_44x_itlb_index(struct kvm_vcpu *vcpu, gva_t eaddr)
 {
 	unsigned int as = !!(vcpu->arch.msr & MSR_IS);
-	unsigned int index;
 
-	index = kvmppc_44x_tlb_index(vcpu, eaddr, vcpu->arch.pid, as);
-	if (index == -1)
-		return NULL;
-	return &vcpu->arch.guest_tlb[index];
+	return kvmppc_44x_tlb_index(vcpu, eaddr, vcpu->arch.pid, as);
 }
 
-struct tlbe *kvmppc_44x_dtlb_search(struct kvm_vcpu *vcpu, gva_t eaddr)
+int kvmppc_44x_dtlb_index(struct kvm_vcpu *vcpu, gva_t eaddr)
 {
 	unsigned int as = !!(vcpu->arch.msr & MSR_DS);
-	unsigned int index;
 
-	index = kvmppc_44x_tlb_index(vcpu, eaddr, vcpu->arch.pid, as);
-	if (index == -1)
-		return NULL;
-	return &vcpu->arch.guest_tlb[index];
+	return kvmppc_44x_tlb_index(vcpu, eaddr, vcpu->arch.pid, as);
 }
 
-static int kvmppc_44x_tlbe_is_writable(struct tlbe *tlbe)
+static void kvmppc_44x_shadow_release(struct kvmppc_vcpu_44x *vcpu_44x,
+                                      unsigned int stlb_index)
 {
-	return tlbe->word2 & (PPC44x_TLB_SW|PPC44x_TLB_UW);
-}
+	struct kvmppc_44x_shadow_ref *ref = &vcpu_44x->shadow_refs[stlb_index];
 
-static void kvmppc_44x_shadow_release(struct kvm_vcpu *vcpu,
-                                      unsigned int index)
-{
-	struct tlbe *stlbe = &vcpu->arch.shadow_tlb[index];
-	struct page *page = vcpu->arch.shadow_pages[index];
+	if (!ref->page)
+		return;
 
-	if (get_tlb_v(stlbe)) {
-		if (kvmppc_44x_tlbe_is_writable(stlbe))
-			kvm_release_page_dirty(page);
-		else
-			kvm_release_page_clean(page);
-	}
+	/* Discard from the TLB. */
+	/* Note: we could actually invalidate a host mapping, if the host overwrote
+	 * this TLB entry since we inserted a guest mapping. */
+	kvmppc_44x_tlbie(stlb_index);
+
+	/* Now release the page. */
+	if (ref->writeable)
+		kvm_release_page_dirty(ref->page);
+	else
+		kvm_release_page_clean(ref->page);
+
+	ref->page = NULL;
+
+	/* XXX set tlb_44x_index to stlb_index? */
+
+	KVMTRACE_1D(STLB_INVAL, &vcpu_44x->vcpu, stlb_index, handler);
 }
 
 void kvmppc_core_destroy_mmu(struct kvm_vcpu *vcpu)
 {
+	struct kvmppc_vcpu_44x *vcpu_44x = to_44x(vcpu);
 	int i;
 
 	for (i = 0; i <= tlb_44x_hwater; i++)
-		kvmppc_44x_shadow_release(vcpu, i);
-}
-
-void kvmppc_tlbe_set_modified(struct kvm_vcpu *vcpu, unsigned int i)
-{
-    vcpu->arch.shadow_tlb_mod[i] = 1;
+		kvmppc_44x_shadow_release(vcpu_44x, i);
 }
 
-/* Caller must ensure that the specified guest TLB entry is safe to insert into
- * the shadow TLB. */
-void kvmppc_mmu_map(struct kvm_vcpu *vcpu, u64 gvaddr, gfn_t gfn, u64 asid,
-                    u32 flags)
+/**
+ * kvmppc_mmu_map -- create a host mapping for guest memory
+ *
+ * If the guest wanted a larger page than the host supports, only the first
+ * host page is mapped here and the rest are demand faulted.
+ *
+ * If the guest wanted a smaller page than the host page size, we map only the
+ * guest-size page (i.e. not a full host page mapping).
+ *
+ * Caller must ensure that the specified guest TLB entry is safe to insert into
+ * the shadow TLB.
+ */
+void kvmppc_mmu_map(struct kvm_vcpu *vcpu, u64 gvaddr, gpa_t gpaddr, u64 asid,
+                    u32 flags, u32 max_bytes, unsigned int gtlb_index)
 {
+	struct kvmppc_44x_tlbe stlbe;
+	struct kvmppc_vcpu_44x *vcpu_44x = to_44x(vcpu);
+	struct kvmppc_44x_shadow_ref *ref;
 	struct page *new_page;
-	struct tlbe *stlbe;
 	hpa_t hpaddr;
+	gfn_t gfn;
 	unsigned int victim;
 
-	/* Future optimization: don't overwrite the TLB entry containing the
-	 * current PC (or stack?). */
-	victim = kvmppc_tlb_44x_pos++;
-	if (kvmppc_tlb_44x_pos > tlb_44x_hwater)
-		kvmppc_tlb_44x_pos = 0;
-	stlbe = &vcpu->arch.shadow_tlb[victim];
+	/* Select TLB entry to clobber. Indirectly guard against races with the TLB
+	 * miss handler by disabling interrupts. */
+	local_irq_disable();
+	victim = ++tlb_44x_index;
+	if (victim > tlb_44x_hwater)
+		victim = 0;
+	tlb_44x_index = victim;
+	local_irq_enable();
 
 	/* Get reference to new page. */
+	gfn = gpaddr >> PAGE_SHIFT;
 	new_page = gfn_to_page(vcpu->kvm, gfn);
 	if (is_error_page(new_page)) {
 		printk(KERN_ERR "Couldn't get guest page for gfn %lx!\n", gfn);
@@ -163,10 +299,8 @@ void kvmppc_mmu_map(struct kvm_vcpu *vcpu, u64 gvaddr, gfn_t gfn, u64 asid,
 	}
 	hpaddr = page_to_phys(new_page);
 
-	/* Drop reference to old page. */
-	kvmppc_44x_shadow_release(vcpu, victim);
-
-	vcpu->arch.shadow_pages[victim] = new_page;
+	/* Invalidate any previous shadow mappings. */
+	kvmppc_44x_shadow_release(vcpu_44x, victim);
 
 	/* XXX Make sure (va, size) doesn't overlap any other
 	 * entries. 440x6 user manual says the result would be
@@ -174,78 +308,193 @@ void kvmppc_mmu_map(struct kvm_vcpu *vcpu, u64 gvaddr, gfn_t gfn, u64 asid,
 
 	/* XXX what about AS? */
 
-	stlbe->tid = !(asid & 0xff);
-
 	/* Force TS=1 for all guest mappings. */
-	/* For now we hardcode 4KB mappings, but it will be important to
-	 * use host large pages in the future. */
-	stlbe->word0 = (gvaddr & PAGE_MASK) | PPC44x_TLB_VALID | PPC44x_TLB_TS
-	               | PPC44x_TLB_4K;
-	stlbe->word1 = (hpaddr & 0xfffffc00) | ((hpaddr >> 32) & 0xf);
-	stlbe->word2 = kvmppc_44x_tlb_shadow_attrib(flags,
-	                                            vcpu->arch.msr & MSR_PR);
-	kvmppc_tlbe_set_modified(vcpu, victim);
+	stlbe.word0 = PPC44x_TLB_VALID | PPC44x_TLB_TS;
+
+	if (max_bytes >= PAGE_SIZE) {
+		/* Guest mapping is larger than or equal to host page size. We can use
+		 * a "native" host mapping. */
+		stlbe.word0 |= (gvaddr & PAGE_MASK) | PPC44x_TLBE_SIZE;
+	} else {
+		/* Guest mapping is smaller than host page size. We must restrict the
+		 * size of the mapping to be at most the smaller of the two, but for
+		 * simplicity we fall back to a 4K mapping (this is probably what the
+		 * guest is using anyways). */
+		stlbe.word0 |= (gvaddr & PAGE_MASK_4K) | PPC44x_TLB_4K;
+
+		/* 'hpaddr' is a host page, which is larger than the mapping we're
+		 * inserting here. To compensate, we must add the in-page offset to the
+		 * sub-page. */
+		hpaddr |= gpaddr & (PAGE_MASK ^ PAGE_MASK_4K);
+	}
 
-	KVMTRACE_5D(STLB_WRITE, vcpu, victim,
-			stlbe->tid, stlbe->word0, stlbe->word1, stlbe->word2,
-			handler);
+	stlbe.word1 = (hpaddr & 0xfffffc00) | ((hpaddr >> 32) & 0xf);
+	stlbe.word2 = kvmppc_44x_tlb_shadow_attrib(flags,
+	                                            vcpu->arch.msr & MSR_PR);
+	stlbe.tid = !(asid & 0xff);
+
+	/* Keep track of the reference so we can properly release it later. */
+	ref = &vcpu_44x->shadow_refs[victim];
+	ref->page = new_page;
+	ref->gtlb_index = gtlb_index;
+	ref->writeable = !!(stlbe.word2 & PPC44x_TLB_UW);
+	ref->tid = stlbe.tid;
+
+	/* Insert shadow mapping into hardware TLB. */
+	kvmppc_44x_tlbe_set_modified(vcpu_44x, victim);
+	kvmppc_44x_tlbwe(victim, &stlbe);
+	KVMTRACE_5D(STLB_WRITE, vcpu, victim, stlbe.tid, stlbe.word0, stlbe.word1,
+	            stlbe.word2, handler);
 }
 
-void kvmppc_mmu_invalidate(struct kvm_vcpu *vcpu, gva_t eaddr,
-                           gva_t eend, u32 asid)
+/* For a particular guest TLB entry, invalidate the corresponding host TLB
+ * mappings and release the host pages. */
+static void kvmppc_44x_invalidate(struct kvm_vcpu *vcpu,
+                                  unsigned int gtlb_index)
 {
-	unsigned int pid = !(asid & 0xff);
+	struct kvmppc_vcpu_44x *vcpu_44x = to_44x(vcpu);
 	int i;
 
-	/* XXX Replace loop with fancy data structures. */
-	for (i = 0; i <= tlb_44x_hwater; i++) {
-		struct tlbe *stlbe = &vcpu->arch.shadow_tlb[i];
-		unsigned int tid;
+	for (i = 0; i < ARRAY_SIZE(vcpu_44x->shadow_refs); i++) {
+		struct kvmppc_44x_shadow_ref *ref = &vcpu_44x->shadow_refs[i];
+		if (ref->gtlb_index == gtlb_index)
+			kvmppc_44x_shadow_release(vcpu_44x, i);
+	}
+}
 
-		if (!get_tlb_v(stlbe))
-			continue;
+void kvmppc_mmu_priv_switch(struct kvm_vcpu *vcpu, int usermode)
+{
+	vcpu->arch.shadow_pid = !usermode;
+}
 
-		if (eend < get_tlb_eaddr(stlbe))
-			continue;
+void kvmppc_set_pid(struct kvm_vcpu *vcpu, u32 new_pid)
+{
+	struct kvmppc_vcpu_44x *vcpu_44x = to_44x(vcpu);
+	int i;
 
-		if (eaddr > get_tlb_end(stlbe))
-			continue;
+	if (unlikely(vcpu->arch.pid == new_pid))
+		return;
 
-		tid = get_tlb_tid(stlbe);
-		if (tid && (tid != pid))
-			continue;
+	vcpu->arch.pid = new_pid;
 
-		kvmppc_44x_shadow_release(vcpu, i);
-		stlbe->word0 = 0;
-		kvmppc_tlbe_set_modified(vcpu, i);
-		KVMTRACE_5D(STLB_INVAL, vcpu, i,
-				stlbe->tid, stlbe->word0, stlbe->word1,
-				stlbe->word2, handler);
+	/* Guest userspace runs with TID=0 mappings and PID=0, to make sure it
+	 * can't access guest kernel mappings (TID=1). When we switch to a new
+	 * guest PID, which will also use host PID=0, we must discard the old guest
+	 * userspace mappings. */
+	for (i = 0; i < ARRAY_SIZE(vcpu_44x->shadow_refs); i++) {
+		struct kvmppc_44x_shadow_ref *ref = &vcpu_44x->shadow_refs[i];
+
+		if (ref->tid == 0)
+			kvmppc_44x_shadow_release(vcpu_44x, i);
 	}
 }
 
-/* Invalidate all mappings on the privilege switch after PID has been changed.
- * The guest always runs with PID=1, so we must clear the entire TLB when
- * switching address spaces. */
-void kvmppc_mmu_priv_switch(struct kvm_vcpu *vcpu, int usermode)
+static int tlbe_is_host_safe(const struct kvm_vcpu *vcpu,
+                             const struct kvmppc_44x_tlbe *tlbe)
 {
-	int i;
+	gpa_t gpa;
 
-	if (vcpu->arch.swap_pid) {
-		/* XXX Replace loop with fancy data structures. */
-		for (i = 0; i <= tlb_44x_hwater; i++) {
-			struct tlbe *stlbe = &vcpu->arch.shadow_tlb[i];
-
-			/* Future optimization: clear only userspace mappings. */
-			kvmppc_44x_shadow_release(vcpu, i);
-			stlbe->word0 = 0;
-			kvmppc_tlbe_set_modified(vcpu, i);
-			KVMTRACE_5D(STLB_INVAL, vcpu, i,
-			            stlbe->tid, stlbe->word0, stlbe->word1,
-			            stlbe->word2, handler);
-		}
-		vcpu->arch.swap_pid = 0;
+	if (!get_tlb_v(tlbe))
+		return 0;
+
+	/* Does it match current guest AS? */
+	/* XXX what about IS != DS? */
+	if (get_tlb_ts(tlbe) != !!(vcpu->arch.msr & MSR_IS))
+		return 0;
+
+	gpa = get_tlb_raddr(tlbe);
+	if (!gfn_to_memslot(vcpu->kvm, gpa >> PAGE_SHIFT))
+		/* Mapping is not for RAM. */
+		return 0;
+
+	return 1;
+}
+
+int kvmppc_44x_emul_tlbwe(struct kvm_vcpu *vcpu, u8 ra, u8 rs, u8 ws)
+{
+	struct kvmppc_vcpu_44x *vcpu_44x = to_44x(vcpu);
+	struct kvmppc_44x_tlbe *tlbe;
+	unsigned int gtlb_index;
+
+	gtlb_index = vcpu->arch.gpr[ra];
+	if (gtlb_index > KVM44x_GUEST_TLB_SIZE) {
+		printk("%s: index %d\n", __func__, gtlb_index);
+		kvmppc_dump_vcpu(vcpu);
+		return EMULATE_FAIL;
 	}
 
-	vcpu->arch.shadow_pid = !usermode;
+	tlbe = &vcpu_44x->guest_tlb[gtlb_index];
+
+	/* Invalidate shadow mappings for the about-to-be-clobbered TLB entry. */
+	if (tlbe->word0 & PPC44x_TLB_VALID)
+		kvmppc_44x_invalidate(vcpu, gtlb_index);
+
+	switch (ws) {
+	case PPC44x_TLB_PAGEID:
+		tlbe->tid = get_mmucr_stid(vcpu);
+		tlbe->word0 = vcpu->arch.gpr[rs];
+		break;
+
+	case PPC44x_TLB_XLAT:
+		tlbe->word1 = vcpu->arch.gpr[rs];
+		break;
+
+	case PPC44x_TLB_ATTRIB:
+		tlbe->word2 = vcpu->arch.gpr[rs];
+		break;
+
+	default:
+		return EMULATE_FAIL;
+	}
+
+	if (tlbe_is_host_safe(vcpu, tlbe)) {
+		u64 asid;
+		gva_t eaddr;
+		gpa_t gpaddr;
+		u32 flags;
+		u32 bytes;
+
+		eaddr = get_tlb_eaddr(tlbe);
+		gpaddr = get_tlb_raddr(tlbe);
+
+		/* Use the advertised page size to mask effective and real addrs. */
+		bytes = get_tlb_bytes(tlbe);
+		eaddr &= ~(bytes - 1);
+		gpaddr &= ~(bytes - 1);
+
+		asid = (tlbe->word0 & PPC44x_TLB_TS) | tlbe->tid;
+		flags = tlbe->word2 & 0xffff;
+
+		kvmppc_mmu_map(vcpu, eaddr, gpaddr, asid, flags, bytes, gtlb_index);
+	}
+
+	KVMTRACE_5D(GTLB_WRITE, vcpu, gtlb_index, tlbe->tid, tlbe->word0,
+	            tlbe->word1, tlbe->word2, handler);
+
+	kvmppc_set_exit_type(vcpu, EMULATED_TLBWE_EXITS);
+	return EMULATE_DONE;
+}
+
+int kvmppc_44x_emul_tlbsx(struct kvm_vcpu *vcpu, u8 rt, u8 ra, u8 rb, u8 rc)
+{
+	u32 ea;
+	int gtlb_index;
+	unsigned int as = get_mmucr_sts(vcpu);
+	unsigned int pid = get_mmucr_stid(vcpu);
+
+	ea = vcpu->arch.gpr[rb];
+	if (ra)
+		ea += vcpu->arch.gpr[ra];
+
+	gtlb_index = kvmppc_44x_tlb_index(vcpu, ea, pid, as);
+	if (rc) {
+		if (gtlb_index < 0)
+			vcpu->arch.cr &= ~0x20000000;
+		else
+			vcpu->arch.cr |= 0x20000000;
+	}
+	vcpu->arch.gpr[rt] = gtlb_index;
+
+	kvmppc_set_exit_type(vcpu, EMULATED_TLBSX_EXITS);
+	return EMULATE_DONE;
 }