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: [<ffffffffa011a6ac>] kvm_set_memory_region+0x29/0x50 [kvm]
 #1:  (&(&kvm->mmu_lock)->rlock){+.+...}, at: [<ffffffffa012262d>] 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:
 [<ffffffff8106c59e>] lockdep_rcu_dereference+0xaa/0xb3
 [<ffffffffa012f6c1>] kvm_mmu_calculate_mmu_pages+0x44/0x7d [kvm]
 [<ffffffffa012263e>] kvm_arch_commit_memory_region+0xb7/0xe2 [kvm]
 [<ffffffffa011a5d7>] __kvm_set_memory_region+0x636/0x6e2 [kvm]
 [<ffffffffa011a6ba>] kvm_set_memory_region+0x37/0x50 [kvm]
 [<ffffffffa015e956>] vmx_set_tss_addr+0x46/0x5a [kvm_intel]
 [<ffffffffa0126592>] kvm_arch_vm_ioctl+0x17a/0xcf8 [kvm]
 [<ffffffff810a8692>] ? unlock_page+0x27/0x2c
 [<ffffffff810bf879>] ? __do_fault+0x3a9/0x3e1
 [<ffffffffa011b12f>] kvm_vm_ioctl+0x364/0x38d [kvm]
 [<ffffffff81060cfa>] ? up_read+0x23/0x3d
 [<ffffffff810f3587>] vfs_ioctl+0x32/0xa6
 [<ffffffff810f3b19>] do_vfs_ioctl+0x495/0x4db
 [<ffffffff810e6b2f>] ? fget_light+0xc2/0x241
 [<ffffffff810e416c>] ? do_sys_open+0x104/0x116
 [<ffffffff81382d6d>] ? retint_swapgs+0xe/0x13
 [<ffffffff810f3ba6>] sys_ioctl+0x47/0x6a
 [<ffffffff810021db>] system_call_fastpath+0x16/0x1b

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index d7bac1f75af0acf0132f0f12a582da3cfbe36e11..d5f4e9161201f648dbaf90ec96c300ec63d6536b 100644 (file)
--- 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 60f09ab3672c9d26453395f70addbb45f6a77d6c..cfa9d1777457894ab96679cfe571084e24ba790f 100644 (file)
--- 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 7a17db1cdcd6c7f4cc5e9e1556f0f423217d0732..0682a393ad9050f96e2ea7ed364d56ff6cbccbc6 100644 (file)
--- 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 0b896ac7e4bb45186072032602782404209be7e5..d0a10b5612e90ab3c97280385d4c791cb3464d7b 100644 (file)
--- 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 58a96e6a234cdae8c2ac9744eb4028087f3fcd10..638248c969994bd968b9600df0120ed82b569537 100644 (file)
--- 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 b7a404722d2b791efa2a9ae12d636ec2e5fd0a83..f4b54458285b0d122e7bb9b0868042924bdf323f 100644 (file)
--- 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 55830638aeb15895fb72ad031f1d62af3fe49c25..1ed030bad59e00d523160671b27306745e341784 100644 (file)
--- 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 80fd3ad3b2de77d246fe8cb9a5df5714609735c3..37ca71ebdba88645ad3a79eec1197998fcbc7dd5 100644 (file)
--- 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 d6351a34b297763f946ccb9e3e90e54a7039b73e..4901ec5061ba3986fa04458d437eccb647200ae6 100644 (file)
--- 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;