From 90d83dc3d49f5101addae962ccc1b4aff66b68d8 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Mon, 19 Apr 2010 17:41:23 +0800 Subject: [PATCH] KVM: use the correct RCU API for PROVE_RCU=y The RCU/SRCU API have already changed for proving RCU usage. I got the following dmesg when PROVE_RCU=y because we used incorrect API. This patch coverts rcu_deference() to srcu_dereference() or family API. =================================================== [ INFO: suspicious rcu_dereference_check() usage. ] --------------------------------------------------- arch/x86/kvm/mmu.c:3020 invoked rcu_dereference_check() without protection! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 0 2 locks held by qemu-system-x86/8550: #0: (&kvm->slots_lock){+.+.+.}, at: [] kvm_set_memory_region+0x29/0x50 [kvm] #1: (&(&kvm->mmu_lock)->rlock){+.+...}, at: [] kvm_arch_commit_memory_region+0xa6/0xe2 [kvm] stack backtrace: Pid: 8550, comm: qemu-system-x86 Not tainted 2.6.34-rc4-tip-01028-g939eab1 #27 Call Trace: [] lockdep_rcu_dereference+0xaa/0xb3 [] kvm_mmu_calculate_mmu_pages+0x44/0x7d [kvm] [] kvm_arch_commit_memory_region+0xb7/0xe2 [kvm] [] __kvm_set_memory_region+0x636/0x6e2 [kvm] [] kvm_set_memory_region+0x37/0x50 [kvm] [] vmx_set_tss_addr+0x46/0x5a [kvm_intel] [] kvm_arch_vm_ioctl+0x17a/0xcf8 [kvm] [] ? unlock_page+0x27/0x2c [] ? __do_fault+0x3a9/0x3e1 [] kvm_vm_ioctl+0x364/0x38d [kvm] [] ? up_read+0x23/0x3d [] vfs_ioctl+0x32/0xa6 [] do_vfs_ioctl+0x495/0x4db [] ? fget_light+0xc2/0x241 [] ? do_sys_open+0x104/0x116 [] ? retint_swapgs+0xe/0x13 [] sys_ioctl+0x47/0x6a [] system_call_fastpath+0x16/0x1b Signed-off-by: Lai Jiangshan Signed-off-by: Avi Kivity --- arch/ia64/kvm/kvm-ia64.c | 2 +- arch/s390/kvm/kvm-s390.h | 2 +- arch/x86/kvm/mmu.c | 7 ++++--- arch/x86/kvm/vmx.c | 2 +- arch/x86/kvm/x86.c | 4 ++-- arch/x86/kvm/x86.h | 7 +++++++ include/linux/kvm_host.h | 7 +++++++ virt/kvm/iommu.c | 4 ++-- virt/kvm/kvm_main.c | 13 ++++++++----- 9 files changed, 33 insertions(+), 15 deletions(-) diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c index d7bac1f..d5f4e91 100644 --- a/arch/ia64/kvm/kvm-ia64.c +++ b/arch/ia64/kvm/kvm-ia64.c @@ -1381,7 +1381,7 @@ static void kvm_release_vm_pages(struct kvm *kvm) int i, j; unsigned long base_gfn; - slots = rcu_dereference(kvm->memslots); + slots = kvm_memslots(kvm); for (i = 0; i < slots->nmemslots; i++) { memslot = &slots->memslots[i]; base_gfn = memslot->base_gfn; diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h index 60f09ab..cfa9d17 100644 --- a/arch/s390/kvm/kvm-s390.h +++ b/arch/s390/kvm/kvm-s390.h @@ -72,7 +72,7 @@ static inline void kvm_s390_vcpu_set_mem(struct kvm_vcpu *vcpu) struct kvm_memslots *memslots; idx = srcu_read_lock(&vcpu->kvm->srcu); - memslots = rcu_dereference(vcpu->kvm->memslots); + memslots = kvm_memslots(vcpu->kvm); mem = &memslots->memslots[0]; diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 7a17db1..0682a393 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -787,7 +787,7 @@ static int kvm_handle_hva(struct kvm *kvm, unsigned long hva, int retval = 0; struct kvm_memslots *slots; - slots = rcu_dereference(kvm->memslots); + slots = kvm_memslots(kvm); for (i = 0; i < slots->nmemslots; i++) { struct kvm_memory_slot *memslot = &slots->memslots[i]; @@ -3016,7 +3016,8 @@ unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm) unsigned int nr_pages = 0; struct kvm_memslots *slots; - slots = rcu_dereference(kvm->memslots); + slots = kvm_memslots(kvm); + for (i = 0; i < slots->nmemslots; i++) nr_pages += slots->memslots[i].npages; @@ -3292,7 +3293,7 @@ static int count_rmaps(struct kvm_vcpu *vcpu) int i, j, k, idx; idx = srcu_read_lock(&kvm->srcu); - slots = rcu_dereference(kvm->memslots); + slots = kvm_memslots(kvm); for (i = 0; i < KVM_MEMORY_SLOTS; ++i) { struct kvm_memory_slot *m = &slots->memslots[i]; struct kvm_rmap_desc *d; diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 0b896ac..d0a10b5 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -1558,7 +1558,7 @@ static gva_t rmode_tss_base(struct kvm *kvm) struct kvm_memslots *slots; gfn_t base_gfn; - slots = rcu_dereference(kvm->memslots); + slots = kvm_memslots(kvm); base_gfn = kvm->memslots->memslots[0].base_gfn + kvm->memslots->memslots[0].npages - 3; return base_gfn << PAGE_SHIFT; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 58a96e6..638248c 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2497,7 +2497,7 @@ gfn_t unalias_gfn_instantiation(struct kvm *kvm, gfn_t gfn) struct kvm_mem_alias *alias; struct kvm_mem_aliases *aliases; - aliases = rcu_dereference(kvm->arch.aliases); + aliases = kvm_aliases(kvm); for (i = 0; i < aliases->naliases; ++i) { alias = &aliases->aliases[i]; @@ -2516,7 +2516,7 @@ gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn) struct kvm_mem_alias *alias; struct kvm_mem_aliases *aliases; - aliases = rcu_dereference(kvm->arch.aliases); + aliases = kvm_aliases(kvm); for (i = 0; i < aliases->naliases; ++i) { alias = &aliases->aliases[i]; diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h index b7a4047..f4b5445 100644 --- a/arch/x86/kvm/x86.h +++ b/arch/x86/kvm/x86.h @@ -65,6 +65,13 @@ static inline int is_paging(struct kvm_vcpu *vcpu) return kvm_read_cr0_bits(vcpu, X86_CR0_PG); } +static inline struct kvm_mem_aliases *kvm_aliases(struct kvm *kvm) +{ + return rcu_dereference_check(kvm->arch.aliases, + srcu_read_lock_held(&kvm->srcu) + || lockdep_is_held(&kvm->slots_lock)); +} + void kvm_before_handle_nmi(struct kvm_vcpu *vcpu); void kvm_after_handle_nmi(struct kvm_vcpu *vcpu); diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 5583063..1ed030b 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -250,6 +250,13 @@ void kvm_exit(void); void kvm_get_kvm(struct kvm *kvm); void kvm_put_kvm(struct kvm *kvm); +static inline struct kvm_memslots *kvm_memslots(struct kvm *kvm) +{ + return rcu_dereference_check(kvm->memslots, + srcu_read_lock_held(&kvm->srcu) + || lockdep_is_held(&kvm->slots_lock)); +} + #define HPA_MSB ((sizeof(hpa_t) * 8) - 1) #define HPA_ERR_MASK ((hpa_t)1 << HPA_MSB) static inline int is_error_hpa(hpa_t hpa) { return hpa >> HPA_MSB; } diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c index 80fd3ad..37ca71e 100644 --- a/virt/kvm/iommu.c +++ b/virt/kvm/iommu.c @@ -78,7 +78,7 @@ static int kvm_iommu_map_memslots(struct kvm *kvm) int i, r = 0; struct kvm_memslots *slots; - slots = rcu_dereference(kvm->memslots); + slots = kvm_memslots(kvm); for (i = 0; i < slots->nmemslots; i++) { r = kvm_iommu_map_pages(kvm, &slots->memslots[i]); @@ -217,7 +217,7 @@ static int kvm_iommu_unmap_memslots(struct kvm *kvm) int i; struct kvm_memslots *slots; - slots = rcu_dereference(kvm->memslots); + slots = kvm_memslots(kvm); for (i = 0; i < slots->nmemslots; i++) { kvm_iommu_put_pages(kvm, slots->memslots[i].base_gfn, diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index d6351a3..4901ec5 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -834,7 +834,7 @@ EXPORT_SYMBOL_GPL(kvm_is_error_hva); struct kvm_memory_slot *gfn_to_memslot_unaliased(struct kvm *kvm, gfn_t gfn) { int i; - struct kvm_memslots *slots = rcu_dereference(kvm->memslots); + struct kvm_memslots *slots = kvm_memslots(kvm); for (i = 0; i < slots->nmemslots; ++i) { struct kvm_memory_slot *memslot = &slots->memslots[i]; @@ -856,7 +856,7 @@ struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn) int kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn) { int i; - struct kvm_memslots *slots = rcu_dereference(kvm->memslots); + struct kvm_memslots *slots = kvm_memslots(kvm); gfn = unalias_gfn_instantiation(kvm, gfn); for (i = 0; i < KVM_MEMORY_SLOTS; ++i) { @@ -900,7 +900,7 @@ out: int memslot_id(struct kvm *kvm, gfn_t gfn) { int i; - struct kvm_memslots *slots = rcu_dereference(kvm->memslots); + struct kvm_memslots *slots = kvm_memslots(kvm); struct kvm_memory_slot *memslot = NULL; gfn = unalias_gfn(kvm, gfn); @@ -1994,7 +1994,9 @@ int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, int len, const void *val) { int i; - struct kvm_io_bus *bus = rcu_dereference(kvm->buses[bus_idx]); + struct kvm_io_bus *bus; + + bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu); for (i = 0; i < bus->dev_count; i++) if (!kvm_iodevice_write(bus->devs[i], addr, len, val)) return 0; @@ -2006,8 +2008,9 @@ int kvm_io_bus_read(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, int len, void *val) { int i; - struct kvm_io_bus *bus = rcu_dereference(kvm->buses[bus_idx]); + struct kvm_io_bus *bus; + bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu); for (i = 0; i < bus->dev_count; i++) if (!kvm_iodevice_read(bus->devs[i], addr, len, val)) return 0; -- 2.7.4