KVM: PPC: Add host MMU Support

In order to support 32 bit Book3S, we need to add code to enable our
shadow MMU to actually add shadow PTEs. This is the module enabling
that support.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

arch/powerpc/kvm/book3s_32_mmu_host.c

+/*
+ * Copyright (C) 2010 SUSE Linux Products GmbH. All rights reserved.
+ *
+ * Authors:
+ *     Alexander Graf <agraf@suse.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#include <linux/kvm_host.h>
+
+#include <asm/kvm_ppc.h>
+#include <asm/kvm_book3s.h>
+#include <asm/mmu-hash32.h>
+#include <asm/machdep.h>
+#include <asm/mmu_context.h>
+#include <asm/hw_irq.h>
+
+/* #define DEBUG_MMU */
+/* #define DEBUG_SR */
+
+#ifdef DEBUG_MMU
+#define dprintk_mmu(a, ...) printk(KERN_INFO a, __VA_ARGS__)
+#else
+#define dprintk_mmu(a, ...) do { } while(0)
+#endif
+
+#ifdef DEBUG_SR
+#define dprintk_sr(a, ...) printk(KERN_INFO a, __VA_ARGS__)
+#else
+#define dprintk_sr(a, ...) do { } while(0)
+#endif
+
+#if PAGE_SHIFT != 12
+#error Unknown page size
+#endif
+
+#ifdef CONFIG_SMP
+#error XXX need to grab mmu_hash_lock
+#endif
+
+#ifdef CONFIG_PTE_64BIT
+#error Only 32 bit pages are supported for now
+#endif
+
+static void invalidate_pte(struct kvm_vcpu *vcpu, struct hpte_cache *pte)
+{
+	volatile u32 *pteg;
+
+	dprintk_mmu("KVM: Flushing SPTE: 0x%llx (0x%llx) -> 0x%llx\n",
+		    pte->pte.eaddr, pte->pte.vpage, pte->host_va);
+
+	pteg = (u32*)pte->slot;
+
+	pteg[0] = 0;
+	asm volatile ("sync");
+	asm volatile ("tlbie %0" : : "r" (pte->pte.eaddr) : "memory");
+	asm volatile ("sync");
+	asm volatile ("tlbsync");
+
+	pte->host_va = 0;
+
+	if (pte->pte.may_write)
+		kvm_release_pfn_dirty(pte->pfn);
+	else
+		kvm_release_pfn_clean(pte->pfn);
+}
+
+void kvmppc_mmu_pte_flush(struct kvm_vcpu *vcpu, u64 _guest_ea, u64 _ea_mask)
+{
+	int i;
+	u32 guest_ea = _guest_ea;
+	u32 ea_mask = _ea_mask;
+
+	dprintk_mmu("KVM: Flushing %d Shadow PTEs: 0x%x & 0x%x\n",
+		    vcpu->arch.hpte_cache_offset, guest_ea, ea_mask);
+	BUG_ON(vcpu->arch.hpte_cache_offset > HPTEG_CACHE_NUM);
+
+	guest_ea &= ea_mask;
+	for (i = 0; i < vcpu->arch.hpte_cache_offset; i++) {
+		struct hpte_cache *pte;
+
+		pte = &vcpu->arch.hpte_cache[i];
+		if (!pte->host_va)
+			continue;
+
+		if ((pte->pte.eaddr & ea_mask) == guest_ea) {
+			invalidate_pte(vcpu, pte);
+		}
+	}
+
+	/* Doing a complete flush -> start from scratch */
+	if (!ea_mask)
+		vcpu->arch.hpte_cache_offset = 0;
+}
+
+void kvmppc_mmu_pte_vflush(struct kvm_vcpu *vcpu, u64 guest_vp, u64 vp_mask)
+{
+	int i;
+
+	dprintk_mmu("KVM: Flushing %d Shadow vPTEs: 0x%llx & 0x%llx\n",
+		    vcpu->arch.hpte_cache_offset, guest_vp, vp_mask);
+	BUG_ON(vcpu->arch.hpte_cache_offset > HPTEG_CACHE_NUM);
+
+	guest_vp &= vp_mask;
+	for (i = 0; i < vcpu->arch.hpte_cache_offset; i++) {
+		struct hpte_cache *pte;
+
+		pte = &vcpu->arch.hpte_cache[i];
+		if (!pte->host_va)
+			continue;
+
+		if ((pte->pte.vpage & vp_mask) == guest_vp) {
+			invalidate_pte(vcpu, pte);
+		}
+	}
+}
+
+void kvmppc_mmu_pte_pflush(struct kvm_vcpu *vcpu, u64 pa_start, u64 pa_end)
+{
+	int i;
+
+	dprintk_mmu("KVM: Flushing %d Shadow pPTEs: 0x%llx & 0x%llx\n",
+		    vcpu->arch.hpte_cache_offset, pa_start, pa_end);
+	BUG_ON(vcpu->arch.hpte_cache_offset > HPTEG_CACHE_NUM);
+
+	for (i = 0; i < vcpu->arch.hpte_cache_offset; i++) {
+		struct hpte_cache *pte;
+
+		pte = &vcpu->arch.hpte_cache[i];
+		if (!pte->host_va)
+			continue;
+
+		if ((pte->pte.raddr >= pa_start) &&
+		    (pte->pte.raddr < pa_end)) {
+			invalidate_pte(vcpu, pte);
+		}
+	}
+}
+
+struct kvmppc_pte *kvmppc_mmu_find_pte(struct kvm_vcpu *vcpu, u64 ea, bool data)
+{
+	int i;
+	u64 guest_vp;
+
+	guest_vp = vcpu->arch.mmu.ea_to_vp(vcpu, ea, false);
+	for (i=0; i<vcpu->arch.hpte_cache_offset; i++) {
+		struct hpte_cache *pte;
+
+		pte = &vcpu->arch.hpte_cache[i];
+		if (!pte->host_va)
+			continue;
+
+		if (pte->pte.vpage == guest_vp)
+			return &pte->pte;
+	}
+
+	return NULL;
+}
+
+static int kvmppc_mmu_hpte_cache_next(struct kvm_vcpu *vcpu)
+{
+	if (vcpu->arch.hpte_cache_offset == HPTEG_CACHE_NUM)
+		kvmppc_mmu_pte_flush(vcpu, 0, 0);
+
+	return vcpu->arch.hpte_cache_offset++;
+}
+
+/* We keep 512 gvsid->hvsid entries, mapping the guest ones to the array using
+ * a hash, so we don't waste cycles on looping */
+static u16 kvmppc_sid_hash(struct kvm_vcpu *vcpu, u64 gvsid)
+{
+	return (u16)(((gvsid >> (SID_MAP_BITS * 7)) & SID_MAP_MASK) ^
+		     ((gvsid >> (SID_MAP_BITS * 6)) & SID_MAP_MASK) ^
+		     ((gvsid >> (SID_MAP_BITS * 5)) & SID_MAP_MASK) ^
+		     ((gvsid >> (SID_MAP_BITS * 4)) & SID_MAP_MASK) ^
+		     ((gvsid >> (SID_MAP_BITS * 3)) & SID_MAP_MASK) ^
+		     ((gvsid >> (SID_MAP_BITS * 2)) & SID_MAP_MASK) ^
+		     ((gvsid >> (SID_MAP_BITS * 1)) & SID_MAP_MASK) ^
+		     ((gvsid >> (SID_MAP_BITS * 0)) & SID_MAP_MASK));
+}
+
+
+static struct kvmppc_sid_map *find_sid_vsid(struct kvm_vcpu *vcpu, u64 gvsid)
+{
+	struct kvmppc_sid_map *map;
+	u16 sid_map_mask;
+
+	if (vcpu->arch.msr & MSR_PR)
+		gvsid |= VSID_PR;
+
+	sid_map_mask = kvmppc_sid_hash(vcpu, gvsid);
+	map = &to_book3s(vcpu)->sid_map[sid_map_mask];
+	if (map->guest_vsid == gvsid) {
+		dprintk_sr("SR: Searching 0x%llx -> 0x%llx\n",
+			    gvsid, map->host_vsid);
+		return map;
+	}
+
+	map = &to_book3s(vcpu)->sid_map[SID_MAP_MASK - sid_map_mask];
+	if (map->guest_vsid == gvsid) {
+		dprintk_sr("SR: Searching 0x%llx -> 0x%llx\n",
+			    gvsid, map->host_vsid);
+		return map;
+	}
+
+	dprintk_sr("SR: Searching 0x%llx -> not found\n", gvsid);
+	return NULL;
+}
+
+extern struct hash_pte *Hash;
+extern unsigned long _SDR1;
+
+static u32 *kvmppc_mmu_get_pteg(struct kvm_vcpu *vcpu, u32 vsid, u32 eaddr,
+				bool primary)
+{
+	u32 page, hash, htabmask;
+	ulong pteg = (ulong)Hash;
+
+	page = (eaddr & ~ESID_MASK) >> 12;
+
+	hash = ((vsid ^ page) << 6);
+	if (!primary)
+		hash = ~hash;
+
+	htabmask = ((_SDR1 & 0x1FF) << 16) | 0xFFC0;
+	hash &= htabmask;
+
+	pteg |= hash;
+
+	dprintk_mmu("htab: %p | hash: %x | htabmask: %x | pteg: %lx\n",
+		Hash, hash, htabmask, pteg);
+
+	return (u32*)pteg;
+}
+
+extern char etext[];
+
+int kvmppc_mmu_map_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *orig_pte)
+{
+	pfn_t hpaddr;
+	u64 va;
+	u64 vsid;
+	struct kvmppc_sid_map *map;
+	volatile u32 *pteg;
+	u32 eaddr = orig_pte->eaddr;
+	u32 pteg0, pteg1;
+	register int rr = 0;
+	bool primary = false;
+	bool evict = false;
+	int hpte_id;
+	struct hpte_cache *pte;
+
+	/* Get host physical address for gpa */
+	hpaddr = gfn_to_pfn(vcpu->kvm, orig_pte->raddr >> PAGE_SHIFT);
+	if (kvm_is_error_hva(hpaddr)) {
+		printk(KERN_INFO "Couldn't get guest page for gfn %llx!\n",
+				 orig_pte->eaddr);
+		return -EINVAL;
+	}
+	hpaddr <<= PAGE_SHIFT;
+
+	/* and write the mapping ea -> hpa into the pt */
+	vcpu->arch.mmu.esid_to_vsid(vcpu, orig_pte->eaddr >> SID_SHIFT, &vsid);
+	map = find_sid_vsid(vcpu, vsid);
+	if (!map) {
+		kvmppc_mmu_map_segment(vcpu, eaddr);
+		map = find_sid_vsid(vcpu, vsid);
+	}
+	BUG_ON(!map);
+
+	vsid = map->host_vsid;
+	va = (vsid << SID_SHIFT) | (eaddr & ~ESID_MASK);
+
+next_pteg:
+	if (rr == 16) {
+		primary = !primary;
+		evict = true;
+		rr = 0;
+	}
+
+	pteg = kvmppc_mmu_get_pteg(vcpu, vsid, eaddr, primary);
+
+	/* not evicting yet */
+	if (!evict && (pteg[rr] & PTE_V)) {
+		rr += 2;
+		goto next_pteg;
+	}
+
+	dprintk_mmu("KVM: old PTEG: %p (%d)\n", pteg, rr);
+	dprintk_mmu("KVM:   %08x - %08x\n", pteg[0], pteg[1]);
+	dprintk_mmu("KVM:   %08x - %08x\n", pteg[2], pteg[3]);
+	dprintk_mmu("KVM:   %08x - %08x\n", pteg[4], pteg[5]);
+	dprintk_mmu("KVM:   %08x - %08x\n", pteg[6], pteg[7]);
+	dprintk_mmu("KVM:   %08x - %08x\n", pteg[8], pteg[9]);
+	dprintk_mmu("KVM:   %08x - %08x\n", pteg[10], pteg[11]);
+	dprintk_mmu("KVM:   %08x - %08x\n", pteg[12], pteg[13]);
+	dprintk_mmu("KVM:   %08x - %08x\n", pteg[14], pteg[15]);
+
+	pteg0 = ((eaddr & 0x0fffffff) >> 22) | (vsid << 7) | PTE_V |
+		(primary ? 0 : PTE_SEC);
+	pteg1 = hpaddr | PTE_M | PTE_R | PTE_C;
+
+	if (orig_pte->may_write) {
+		pteg1 |= PP_RWRW;
+		mark_page_dirty(vcpu->kvm, orig_pte->raddr >> PAGE_SHIFT);
+	} else {
+		pteg1 |= PP_RWRX;
+	}
+
+	local_irq_disable();
+
+	if (pteg[rr]) {
+		pteg[rr] = 0;
+		asm volatile ("sync");
+	}
+	pteg[rr + 1] = pteg1;
+	pteg[rr] = pteg0;
+	asm volatile ("sync");
+
+	local_irq_enable();
+
+	dprintk_mmu("KVM: new PTEG: %p\n", pteg);
+	dprintk_mmu("KVM:   %08x - %08x\n", pteg[0], pteg[1]);
+	dprintk_mmu("KVM:   %08x - %08x\n", pteg[2], pteg[3]);
+	dprintk_mmu("KVM:   %08x - %08x\n", pteg[4], pteg[5]);
+	dprintk_mmu("KVM:   %08x - %08x\n", pteg[6], pteg[7]);
+	dprintk_mmu("KVM:   %08x - %08x\n", pteg[8], pteg[9]);
+	dprintk_mmu("KVM:   %08x - %08x\n", pteg[10], pteg[11]);
+	dprintk_mmu("KVM:   %08x - %08x\n", pteg[12], pteg[13]);
+	dprintk_mmu("KVM:   %08x - %08x\n", pteg[14], pteg[15]);
+
+
+	/* Now tell our Shadow PTE code about the new page */
+
+	hpte_id = kvmppc_mmu_hpte_cache_next(vcpu);
+	pte = &vcpu->arch.hpte_cache[hpte_id];
+
+	dprintk_mmu("KVM: %c%c Map 0x%llx: [%lx] 0x%llx (0x%llx) -> %lx\n",
+		    orig_pte->may_write ? 'w' : '-',
+		    orig_pte->may_execute ? 'x' : '-',
+		    orig_pte->eaddr, (ulong)pteg, va,
+		    orig_pte->vpage, hpaddr);
+
+	pte->slot = (ulong)&pteg[rr];
+	pte->host_va = va;
+	pte->pte = *orig_pte;
+	pte->pfn = hpaddr >> PAGE_SHIFT;
+
+	return 0;
+}
+
+static struct kvmppc_sid_map *create_sid_map(struct kvm_vcpu *vcpu, u64 gvsid)
+{
+	struct kvmppc_sid_map *map;
+	struct kvmppc_vcpu_book3s *vcpu_book3s = to_book3s(vcpu);
+	u16 sid_map_mask;
+	static int backwards_map = 0;
+
+	if (vcpu->arch.msr & MSR_PR)
+		gvsid |= VSID_PR;
+
+	/* We might get collisions that trap in preceding order, so let's
+	   map them differently */
+
+	sid_map_mask = kvmppc_sid_hash(vcpu, gvsid);
+	if (backwards_map)
+		sid_map_mask = SID_MAP_MASK - sid_map_mask;
+
+	map = &to_book3s(vcpu)->sid_map[sid_map_mask];
+
+	/* Make sure we're taking the other map next time */
+	backwards_map = !backwards_map;
+
+	/* Uh-oh ... out of mappings. Let's flush! */
+	if (vcpu_book3s->vsid_next >= vcpu_book3s->vsid_max) {
+		vcpu_book3s->vsid_next = vcpu_book3s->vsid_first;
+		memset(vcpu_book3s->sid_map, 0,
+		       sizeof(struct kvmppc_sid_map) * SID_MAP_NUM);
+		kvmppc_mmu_pte_flush(vcpu, 0, 0);
+		kvmppc_mmu_flush_segments(vcpu);
+	}
+	map->host_vsid = vcpu_book3s->vsid_next;
+
+	/* Would have to be 111 to be completely aligned with the rest of
+	   Linux, but that is just way too little space! */
+	vcpu_book3s->vsid_next+=1;
+
+	map->guest_vsid = gvsid;
+	map->valid = true;
+
+	return map;
+}
+
+int kvmppc_mmu_map_segment(struct kvm_vcpu *vcpu, ulong eaddr)
+{
+	u32 esid = eaddr >> SID_SHIFT;
+	u64 gvsid;
+	u32 sr;
+	struct kvmppc_sid_map *map;
+	struct kvmppc_book3s_shadow_vcpu *svcpu = to_svcpu(vcpu);
+
+	if (vcpu->arch.mmu.esid_to_vsid(vcpu, esid, &gvsid)) {
+		/* Invalidate an entry */
+		svcpu->sr[esid] = SR_INVALID;
+		return -ENOENT;
+	}
+
+	map = find_sid_vsid(vcpu, gvsid);
+	if (!map)
+		map = create_sid_map(vcpu, gvsid);
+
+	map->guest_esid = esid;
+	sr = map->host_vsid | SR_KP;
+	svcpu->sr[esid] = sr;
+
+	dprintk_sr("MMU: mtsr %d, 0x%x\n", esid, sr);
+
+	return 0;
+}
+
+void kvmppc_mmu_flush_segments(struct kvm_vcpu *vcpu)
+{
+	int i;
+	struct kvmppc_book3s_shadow_vcpu *svcpu = to_svcpu(vcpu);
+
+	dprintk_sr("MMU: flushing all segments (%d)\n", ARRAY_SIZE(svcpu->sr));
+	for (i = 0; i < ARRAY_SIZE(svcpu->sr); i++)
+		svcpu->sr[i] = SR_INVALID;
+}
+
+void kvmppc_mmu_destroy(struct kvm_vcpu *vcpu)
+{
+	kvmppc_mmu_pte_flush(vcpu, 0, 0);
+	preempt_disable();
+	__destroy_context(to_book3s(vcpu)->context_id);
+	preempt_enable();
+}
+
+/* From mm/mmu_context_hash32.c */
+#define CTX_TO_VSID(ctx) (((ctx) * (897 * 16)) & 0xffffff)
+
+int kvmppc_mmu_init(struct kvm_vcpu *vcpu)
+{
+	struct kvmppc_vcpu_book3s *vcpu3s = to_book3s(vcpu);
+	int err;
+
+	err = __init_new_context();
+	if (err < 0)
+		return -1;
+	vcpu3s->context_id = err;
+
+	vcpu3s->vsid_max = CTX_TO_VSID(vcpu3s->context_id + 1) - 1;
+	vcpu3s->vsid_first = CTX_TO_VSID(vcpu3s->context_id);
+
+#if 0 /* XXX still doesn't guarantee uniqueness */
+	/* We could collide with the Linux vsid space because the vsid
+	 * wraps around at 24 bits. We're safe if we do our own space
+	 * though, so let's always set the highest bit. */
+
+	vcpu3s->vsid_max |= 0x00800000;
+	vcpu3s->vsid_first |= 0x00800000;
+#endif
+	BUG_ON(vcpu3s->vsid_max < vcpu3s->vsid_first);
+
+	vcpu3s->vsid_next = vcpu3s->vsid_first;
+
+	return 0;
+}