Merge branch 'next' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM changes from Avi Kivity:
 "Changes include additional instruction emulation, page-crossing MMIO,
  faster dirty logging, preventing the watchdog from killing a stopped
  guest, module autoload, a new MSI ABI, and some minor optimizations
  and fixes.  Outside x86 we have a small s390 and a very large ppc
  update.

  Regarding the new (for kvm) rebaseless workflow, some of the patches
  that were merged before we switch trees had to be rebased, while
  others are true pulls.  In either case the signoffs should be correct
  now."

Fix up trivial conflicts in Documentation/feature-removal-schedule.txt
arch/powerpc/kvm/book3s_segment.S and arch/x86/include/asm/kvm_para.h.

I suspect the kvm_para.h resolution ends up doing the "do I have cpuid"
check effectively twice (it was done differently in two different
commits), but better safe than sorry ;)

* 'next' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (125 commits)
  KVM: make asm-generic/kvm_para.h have an ifdef __KERNEL__ block
  KVM: s390: onereg for timer related registers
  KVM: s390: epoch difference and TOD programmable field
  KVM: s390: KVM_GET/SET_ONEREG for s390
  KVM: s390: add capability indicating COW support
  KVM: Fix mmu_reload() clash with nested vmx event injection
  KVM: MMU: Don't use RCU for lockless shadow walking
  KVM: VMX: Optimize %ds, %es reload
  KVM: VMX: Fix %ds/%es clobber
  KVM: x86 emulator: convert bsf/bsr instructions to emulate_2op_SrcV_nobyte()
  KVM: VMX: unlike vmcs on fail path
  KVM: PPC: Emulator: clean up SPR reads and writes
  KVM: PPC: Emulator: clean up instruction parsing
  kvm/powerpc: Add new ioctl to retreive server MMU infos
  kvm/book3s: Make kernel emulated H_PUT_TCE available for "PR" KVM
  KVM: PPC: bookehv: Fix r8/r13 storing in level exception handler
  KVM: PPC: Book3S: Enable IRQs during exit handling
  KVM: PPC: Fix PR KVM on POWER7 bare metal
  KVM: PPC: Fix stbux emulation
  KVM: PPC: bookehv: Use lwz/stw instead of PPC_LL/PPC_STL for 32-bit fields
  ...

1 files changed, 197 insertions, 148 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 4cb1642..72102e0 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -135,8 +135,6 @@ module_param(dbg, bool, 0644);
 #define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK \
 			| PT64_NX_MASK)
 
-#define PTE_LIST_EXT 4
-
 #define ACC_EXEC_MASK    1
 #define ACC_WRITE_MASK   PT_WRITABLE_MASK
 #define ACC_USER_MASK    PT_USER_MASK
@@ -151,6 +149,9 @@ module_param(dbg, bool, 0644);
 
 #define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)
 
+/* make pte_list_desc fit well in cache line */
+#define PTE_LIST_EXT 3
+
 struct pte_list_desc {
 	u64 *sptes[PTE_LIST_EXT];
 	struct pte_list_desc *more;
@@ -550,19 +551,29 @@ static u64 mmu_spte_get_lockless(u64 *sptep)
 
 static void walk_shadow_page_lockless_begin(struct kvm_vcpu *vcpu)
 {
-	rcu_read_lock();
-	atomic_inc(&vcpu->kvm->arch.reader_counter);
-
-	/* Increase the counter before walking shadow page table */
-	smp_mb__after_atomic_inc();
+	/*
+	 * Prevent page table teardown by making any free-er wait during
+	 * kvm_flush_remote_tlbs() IPI to all active vcpus.
+	 */
+	local_irq_disable();
+	vcpu->mode = READING_SHADOW_PAGE_TABLES;
+	/*
+	 * Make sure a following spte read is not reordered ahead of the write
+	 * to vcpu->mode.
+	 */
+	smp_mb();
 }
 
 static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu)
 {
-	/* Decrease the counter after walking shadow page table finished */
-	smp_mb__before_atomic_dec();
-	atomic_dec(&vcpu->kvm->arch.reader_counter);
-	rcu_read_unlock();
+	/*
+	 * Make sure the write to vcpu->mode is not reordered in front of
+	 * reads to sptes.  If it does, kvm_commit_zap_page() can see us
+	 * OUTSIDE_GUEST_MODE and proceed to free the shadow page table.
+	 */
+	smp_mb();
+	vcpu->mode = OUTSIDE_GUEST_MODE;
+	local_irq_enable();
 }
 
 static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
@@ -841,32 +852,6 @@ static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte,
 	return count;
 }
 
-static u64 *pte_list_next(unsigned long *pte_list, u64 *spte)
-{
-	struct pte_list_desc *desc;
-	u64 *prev_spte;
-	int i;
-
-	if (!*pte_list)
-		return NULL;
-	else if (!(*pte_list & 1)) {
-		if (!spte)
-			return (u64 *)*pte_list;
-		return NULL;
-	}
-	desc = (struct pte_list_desc *)(*pte_list & ~1ul);
-	prev_spte = NULL;
-	while (desc) {
-		for (i = 0; i < PTE_LIST_EXT && desc->sptes[i]; ++i) {
-			if (prev_spte == spte)
-				return desc->sptes[i];
-			prev_spte = desc->sptes[i];
-		}
-		desc = desc->more;
-	}
-	return NULL;
-}
-
 static void
 pte_list_desc_remove_entry(unsigned long *pte_list, struct pte_list_desc *desc,
 			   int i, struct pte_list_desc *prev_desc)
@@ -987,11 +972,6 @@ static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
 	return pte_list_add(vcpu, spte, rmapp);
 }
 
-static u64 *rmap_next(unsigned long *rmapp, u64 *spte)
-{
-	return pte_list_next(rmapp, spte);
-}
-
 static void rmap_remove(struct kvm *kvm, u64 *spte)
 {
 	struct kvm_mmu_page *sp;
@@ -1004,106 +984,201 @@ static void rmap_remove(struct kvm *kvm, u64 *spte)
 	pte_list_remove(spte, rmapp);
 }
 
+/*
+ * Used by the following functions to iterate through the sptes linked by a
+ * rmap.  All fields are private and not assumed to be used outside.
+ */
+struct rmap_iterator {
+	/* private fields */
+	struct pte_list_desc *desc;	/* holds the sptep if not NULL */
+	int pos;			/* index of the sptep */
+};
+
+/*
+ * Iteration must be started by this function.  This should also be used after
+ * removing/dropping sptes from the rmap link because in such cases the
+ * information in the itererator may not be valid.
+ *
+ * Returns sptep if found, NULL otherwise.
+ */
+static u64 *rmap_get_first(unsigned long rmap, struct rmap_iterator *iter)
+{
+	if (!rmap)
+		return NULL;
+
+	if (!(rmap & 1)) {
+		iter->desc = NULL;
+		return (u64 *)rmap;
+	}
+
+	iter->desc = (struct pte_list_desc *)(rmap & ~1ul);
+	iter->pos = 0;
+	return iter->desc->sptes[iter->pos];
+}
+
+/*
+ * Must be used with a valid iterator: e.g. after rmap_get_first().
+ *
+ * Returns sptep if found, NULL otherwise.
+ */
+static u64 *rmap_get_next(struct rmap_iterator *iter)
+{
+	if (iter->desc) {
+		if (iter->pos < PTE_LIST_EXT - 1) {
+			u64 *sptep;
+
+			++iter->pos;
+			sptep = iter->desc->sptes[iter->pos];
+			if (sptep)
+				return sptep;
+		}
+
+		iter->desc = iter->desc->more;
+
+		if (iter->desc) {
+			iter->pos = 0;
+			/* desc->sptes[0] cannot be NULL */
+			return iter->desc->sptes[iter->pos];
+		}
+	}
+
+	return NULL;
+}
+
 static void drop_spte(struct kvm *kvm, u64 *sptep)
 {
 	if (mmu_spte_clear_track_bits(sptep))
 		rmap_remove(kvm, sptep);
 }
 
-int kvm_mmu_rmap_write_protect(struct kvm *kvm, u64 gfn,
-			       struct kvm_memory_slot *slot)
+static int __rmap_write_protect(struct kvm *kvm, unsigned long *rmapp, int level)
 {
-	unsigned long *rmapp;
-	u64 *spte;
-	int i, write_protected = 0;
-
-	rmapp = __gfn_to_rmap(gfn, PT_PAGE_TABLE_LEVEL, slot);
-	spte = rmap_next(rmapp, NULL);
-	while (spte) {
-		BUG_ON(!(*spte & PT_PRESENT_MASK));
-		rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
-		if (is_writable_pte(*spte)) {
-			mmu_spte_update(spte, *spte & ~PT_WRITABLE_MASK);
-			write_protected = 1;
+	u64 *sptep;
+	struct rmap_iterator iter;
+	int write_protected = 0;
+
+	for (sptep = rmap_get_first(*rmapp, &iter); sptep;) {
+		BUG_ON(!(*sptep & PT_PRESENT_MASK));
+		rmap_printk("rmap_write_protect: spte %p %llx\n", sptep, *sptep);
+
+		if (!is_writable_pte(*sptep)) {
+			sptep = rmap_get_next(&iter);
+			continue;
 		}
-		spte = rmap_next(rmapp, spte);
-	}
 
-	/* check for huge page mappings */
-	for (i = PT_DIRECTORY_LEVEL;
-	     i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
-		rmapp = __gfn_to_rmap(gfn, i, slot);
-		spte = rmap_next(rmapp, NULL);
-		while (spte) {
-			BUG_ON(!(*spte & PT_PRESENT_MASK));
-			BUG_ON(!is_large_pte(*spte));
-			pgprintk("rmap_write_protect(large): spte %p %llx %lld\n", spte, *spte, gfn);
-			if (is_writable_pte(*spte)) {
-				drop_spte(kvm, spte);
-				--kvm->stat.lpages;
-				spte = NULL;
-				write_protected = 1;
-			}
-			spte = rmap_next(rmapp, spte);
+		if (level == PT_PAGE_TABLE_LEVEL) {
+			mmu_spte_update(sptep, *sptep & ~PT_WRITABLE_MASK);
+			sptep = rmap_get_next(&iter);
+		} else {
+			BUG_ON(!is_large_pte(*sptep));
+			drop_spte(kvm, sptep);
+			--kvm->stat.lpages;
+			sptep = rmap_get_first(*rmapp, &iter);
 		}
+
+		write_protected = 1;
 	}
 
 	return write_protected;
 }
 
+/**
+ * kvm_mmu_write_protect_pt_masked - write protect selected PT level pages
+ * @kvm: kvm instance
+ * @slot: slot to protect
+ * @gfn_offset: start of the BITS_PER_LONG pages we care about
+ * @mask: indicates which pages we should protect
+ *
+ * Used when we do not need to care about huge page mappings: e.g. during dirty
+ * logging we do not have any such mappings.
+ */
+void kvm_mmu_write_protect_pt_masked(struct kvm *kvm,
+				     struct kvm_memory_slot *slot,
+				     gfn_t gfn_offset, unsigned long mask)
+{
+	unsigned long *rmapp;
+
+	while (mask) {
+		rmapp = &slot->rmap[gfn_offset + __ffs(mask)];
+		__rmap_write_protect(kvm, rmapp, PT_PAGE_TABLE_LEVEL);
+
+		/* clear the first set bit */
+		mask &= mask - 1;
+	}
+}
+
 static int rmap_write_protect(struct kvm *kvm, u64 gfn)
 {
 	struct kvm_memory_slot *slot;
+	unsigned long *rmapp;
+	int i;
+	int write_protected = 0;
 
 	slot = gfn_to_memslot(kvm, gfn);
-	return kvm_mmu_rmap_write_protect(kvm, gfn, slot);
+
+	for (i = PT_PAGE_TABLE_LEVEL;
+	     i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
+		rmapp = __gfn_to_rmap(gfn, i, slot);
+		write_protected |= __rmap_write_protect(kvm, rmapp, i);
+	}
+
+	return write_protected;
 }
 
 static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp,
 			   unsigned long data)
 {
-	u64 *spte;
+	u64 *sptep;
+	struct rmap_iterator iter;
 	int need_tlb_flush = 0;
 
-	while ((spte = rmap_next(rmapp, NULL))) {
-		BUG_ON(!(*spte & PT_PRESENT_MASK));
-		rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", spte, *spte);
-		drop_spte(kvm, spte);
+	while ((sptep = rmap_get_first(*rmapp, &iter))) {
+		BUG_ON(!(*sptep & PT_PRESENT_MASK));
+		rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", sptep, *sptep);
+
+		drop_spte(kvm, sptep);
 		need_tlb_flush = 1;
 	}
+
 	return need_tlb_flush;
 }
 
 static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp,
 			     unsigned long data)
 {
+	u64 *sptep;
+	struct rmap_iterator iter;
 	int need_flush = 0;
-	u64 *spte, new_spte;
+	u64 new_spte;
 	pte_t *ptep = (pte_t *)data;
 	pfn_t new_pfn;
 
 	WARN_ON(pte_huge(*ptep));
 	new_pfn = pte_pfn(*ptep);
-	spte = rmap_next(rmapp, NULL);
-	while (spte) {
-		BUG_ON(!is_shadow_present_pte(*spte));
-		rmap_printk("kvm_set_pte_rmapp: spte %p %llx\n", spte, *spte);
+
+	for (sptep = rmap_get_first(*rmapp, &iter); sptep;) {
+		BUG_ON(!is_shadow_present_pte(*sptep));
+		rmap_printk("kvm_set_pte_rmapp: spte %p %llx\n", sptep, *sptep);
+
 		need_flush = 1;
+
 		if (pte_write(*ptep)) {
-			drop_spte(kvm, spte);
-			spte = rmap_next(rmapp, NULL);
+			drop_spte(kvm, sptep);
+			sptep = rmap_get_first(*rmapp, &iter);
 		} else {
-			new_spte = *spte &~ (PT64_BASE_ADDR_MASK);
+			new_spte = *sptep & ~PT64_BASE_ADDR_MASK;
 			new_spte |= (u64)new_pfn << PAGE_SHIFT;
 
 			new_spte &= ~PT_WRITABLE_MASK;
 			new_spte &= ~SPTE_HOST_WRITEABLE;
 			new_spte &= ~shadow_accessed_mask;
-			mmu_spte_clear_track_bits(spte);
-			mmu_spte_set(spte, new_spte);
-			spte = rmap_next(rmapp, spte);
+
+			mmu_spte_clear_track_bits(sptep);
+			mmu_spte_set(sptep, new_spte);
+			sptep = rmap_get_next(&iter);
 		}
 	}
+
 	if (need_flush)
 		kvm_flush_remote_tlbs(kvm);
 
@@ -1162,7 +1237,8 @@ void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
 static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
 			 unsigned long data)
 {
-	u64 *spte;
+	u64 *sptep;
+	struct rmap_iterator iter;
 	int young = 0;
 
 	/*
@@ -1175,25 +1251,24 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
 	if (!shadow_accessed_mask)
 		return kvm_unmap_rmapp(kvm, rmapp, data);
 
-	spte = rmap_next(rmapp, NULL);
-	while (spte) {
-		int _young;
-		u64 _spte = *spte;
-		BUG_ON(!(_spte & PT_PRESENT_MASK));
-		_young = _spte & PT_ACCESSED_MASK;
-		if (_young) {
+	for (sptep = rmap_get_first(*rmapp, &iter); sptep;
+	     sptep = rmap_get_next(&iter)) {
+		BUG_ON(!(*sptep & PT_PRESENT_MASK));
+
+		if (*sptep & PT_ACCESSED_MASK) {
 			young = 1;
-			clear_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte);
+			clear_bit(PT_ACCESSED_SHIFT, (unsigned long *)sptep);
 		}
-		spte = rmap_next(rmapp, spte);
 	}
+
 	return young;
 }
 
 static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
 			      unsigned long data)
 {
-	u64 *spte;
+	u64 *sptep;
+	struct rmap_iterator iter;
 	int young = 0;
 
 	/*
@@ -1204,16 +1279,14 @@ static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
 	if (!shadow_accessed_mask)
 		goto out;
 
-	spte = rmap_next(rmapp, NULL);
-	while (spte) {
-		u64 _spte = *spte;
-		BUG_ON(!(_spte & PT_PRESENT_MASK));
-		young = _spte & PT_ACCESSED_MASK;
-		if (young) {
+	for (sptep = rmap_get_first(*rmapp, &iter); sptep;
+	     sptep = rmap_get_next(&iter)) {
+		BUG_ON(!(*sptep & PT_PRESENT_MASK));
+
+		if (*sptep & PT_ACCESSED_MASK) {
 			young = 1;
 			break;
 		}
-		spte = rmap_next(rmapp, spte);
 	}
 out:
 	return young;
@@ -1865,10 +1938,11 @@ static void kvm_mmu_put_page(struct kvm_mmu_page *sp, u64 *parent_pte)
 
 static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp)
 {
-	u64 *parent_pte;
+	u64 *sptep;
+	struct rmap_iterator iter;
 
-	while ((parent_pte = pte_list_next(&sp->parent_ptes, NULL)))
-		drop_parent_pte(sp, parent_pte);
+	while ((sptep = rmap_get_first(sp->parent_ptes, &iter)))
+		drop_parent_pte(sp, sptep);
 }
 
 static int mmu_zap_unsync_children(struct kvm *kvm,
@@ -1925,30 +1999,6 @@ static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
 	return ret;
 }
 
-static void kvm_mmu_isolate_pages(struct list_head *invalid_list)
-{
-	struct kvm_mmu_page *sp;
-
-	list_for_each_entry(sp, invalid_list, link)
-		kvm_mmu_isolate_page(sp);
-}
-
-static void free_pages_rcu(struct rcu_head *head)
-{
-	struct kvm_mmu_page *next, *sp;
-
-	sp = container_of(head, struct kvm_mmu_page, rcu);
-	while (sp) {
-		if (!list_empty(&sp->link))
-			next = list_first_entry(&sp->link,
-				      struct kvm_mmu_page, link);
-		else
-			next = NULL;
-		kvm_mmu_free_page(sp);
-		sp = next;
-	}
-}
-
 static void kvm_mmu_commit_zap_page(struct kvm *kvm,
 				    struct list_head *invalid_list)
 {
@@ -1957,17 +2007,17 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm,
 	if (list_empty(invalid_list))
 		return;
 
-	kvm_flush_remote_tlbs(kvm);
-
-	if (atomic_read(&kvm->arch.reader_counter)) {
-		kvm_mmu_isolate_pages(invalid_list);
-		sp = list_first_entry(invalid_list, struct kvm_mmu_page, link);
-		list_del_init(invalid_list);
+	/*
+	 * wmb: make sure everyone sees our modifications to the page tables
+	 * rmb: make sure we see changes to vcpu->mode
+	 */
+	smp_mb();
 
-		trace_kvm_mmu_delay_free_pages(sp);
-		call_rcu(&sp->rcu, free_pages_rcu);
-		return;
-	}
+	/*
+	 * Wait for all vcpus to exit guest mode and/or lockless shadow
+	 * page table walks.
+	 */
+	kvm_flush_remote_tlbs(kvm);
 
 	do {
 		sp = list_first_entry(invalid_list, struct kvm_mmu_page, link);
@@ -1975,7 +2025,6 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm,
 		kvm_mmu_isolate_page(sp);
 		kvm_mmu_free_page(sp);
 	} while (!list_empty(invalid_list));
-
 }
 
 /*
@@ -3554,7 +3603,7 @@ static bool detect_write_flooding(struct kvm_mmu_page *sp)
 	 * Skip write-flooding detected for the sp whose level is 1, because
 	 * it can become unsync, then the guest page is not write-protected.
 	 */
-	if (sp->role.level == 1)
+	if (sp->role.level == PT_PAGE_TABLE_LEVEL)
 		return false;
 
 	return ++sp->write_flooding_count >= 3;