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authorLinus Torvalds <torvalds@linux-foundation.org>2017-01-13 17:06:24 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-01-13 17:06:24 -0800
commit406732c932d47715395345ba036a3d58341cad55 (patch)
treeea4060958d1a6d18417d6088a523d47f72656ffb
parenta65c92597dc7556eaa219a70336d66c058a9627c (diff)
parent33ab91103b3415e12457e3104f0e4517ce12d0f3 (diff)
downloadlinux-406732c932d47715395345ba036a3d58341cad55.tar.bz2
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM fixes from Paolo Bonzini: - fix for module unload vs deferred jump labels (note: there might be other buggy modules!) - two NULL pointer dereferences from syzkaller - also syzkaller: fix emulation of fxsave/fxrstor/sgdt/sidt, problem made worse during this merge window, "just" kernel memory leak on releases - fix emulation of "mov ss" - somewhat serious on AMD, less so on Intel * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: x86: fix emulation of "MOV SS, null selector" KVM: x86: fix NULL deref in vcpu_scan_ioapic KVM: eventfd: fix NULL deref irqbypass consumer KVM: x86: Introduce segmented_write_std KVM: x86: flush pending lapic jump label updates on module unload jump_labels: API for flushing deferred jump label updates
-rw-r--r--arch/x86/kvm/emulate.c70
-rw-r--r--arch/x86/kvm/lapic.c6
-rw-r--r--arch/x86/kvm/lapic.h1
-rw-r--r--arch/x86/kvm/x86.c3
-rw-r--r--include/linux/jump_label_ratelimit.h5
-rw-r--r--kernel/jump_label.c7
-rw-r--r--virt/lib/irqbypass.c4
7 files changed, 80 insertions, 16 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 56628a44668b..cedbba0f3402 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -818,6 +818,20 @@ static int segmented_read_std(struct x86_emulate_ctxt *ctxt,
return ctxt->ops->read_std(ctxt, linear, data, size, &ctxt->exception);
}
+static int segmented_write_std(struct x86_emulate_ctxt *ctxt,
+ struct segmented_address addr,
+ void *data,
+ unsigned int size)
+{
+ int rc;
+ ulong linear;
+
+ rc = linearize(ctxt, addr, size, true, &linear);
+ if (rc != X86EMUL_CONTINUE)
+ return rc;
+ return ctxt->ops->write_std(ctxt, linear, data, size, &ctxt->exception);
+}
+
/*
* Prefetch the remaining bytes of the instruction without crossing page
* boundary if they are not in fetch_cache yet.
@@ -1571,7 +1585,6 @@ static int write_segment_descriptor(struct x86_emulate_ctxt *ctxt,
&ctxt->exception);
}
-/* Does not support long mode */
static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
u16 selector, int seg, u8 cpl,
enum x86_transfer_type transfer,
@@ -1608,20 +1621,34 @@ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
rpl = selector & 3;
- /* NULL selector is not valid for TR, CS and SS (except for long mode) */
- if ((seg == VCPU_SREG_CS
- || (seg == VCPU_SREG_SS
- && (ctxt->mode != X86EMUL_MODE_PROT64 || rpl != cpl))
- || seg == VCPU_SREG_TR)
- && null_selector)
- goto exception;
-
/* TR should be in GDT only */
if (seg == VCPU_SREG_TR && (selector & (1 << 2)))
goto exception;
- if (null_selector) /* for NULL selector skip all following checks */
+ /* NULL selector is not valid for TR, CS and (except for long mode) SS */
+ if (null_selector) {
+ if (seg == VCPU_SREG_CS || seg == VCPU_SREG_TR)
+ goto exception;
+
+ if (seg == VCPU_SREG_SS) {
+ if (ctxt->mode != X86EMUL_MODE_PROT64 || rpl != cpl)
+ goto exception;
+
+ /*
+ * ctxt->ops->set_segment expects the CPL to be in
+ * SS.DPL, so fake an expand-up 32-bit data segment.
+ */
+ seg_desc.type = 3;
+ seg_desc.p = 1;
+ seg_desc.s = 1;
+ seg_desc.dpl = cpl;
+ seg_desc.d = 1;
+ seg_desc.g = 1;
+ }
+
+ /* Skip all following checks */
goto load;
+ }
ret = read_segment_descriptor(ctxt, selector, &seg_desc, &desc_addr);
if (ret != X86EMUL_CONTINUE)
@@ -1737,6 +1764,21 @@ static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
u16 selector, int seg)
{
u8 cpl = ctxt->ops->cpl(ctxt);
+
+ /*
+ * None of MOV, POP and LSS can load a NULL selector in CPL=3, but
+ * they can load it at CPL<3 (Intel's manual says only LSS can,
+ * but it's wrong).
+ *
+ * However, the Intel manual says that putting IST=1/DPL=3 in
+ * an interrupt gate will result in SS=3 (the AMD manual instead
+ * says it doesn't), so allow SS=3 in __load_segment_descriptor
+ * and only forbid it here.
+ */
+ if (seg == VCPU_SREG_SS && selector == 3 &&
+ ctxt->mode == X86EMUL_MODE_PROT64)
+ return emulate_exception(ctxt, GP_VECTOR, 0, true);
+
return __load_segment_descriptor(ctxt, selector, seg, cpl,
X86_TRANSFER_NONE, NULL);
}
@@ -3685,8 +3727,8 @@ static int emulate_store_desc_ptr(struct x86_emulate_ctxt *ctxt,
}
/* Disable writeback. */
ctxt->dst.type = OP_NONE;
- return segmented_write(ctxt, ctxt->dst.addr.mem,
- &desc_ptr, 2 + ctxt->op_bytes);
+ return segmented_write_std(ctxt, ctxt->dst.addr.mem,
+ &desc_ptr, 2 + ctxt->op_bytes);
}
static int em_sgdt(struct x86_emulate_ctxt *ctxt)
@@ -3932,7 +3974,7 @@ static int em_fxsave(struct x86_emulate_ctxt *ctxt)
else
size = offsetof(struct fxregs_state, xmm_space[0]);
- return segmented_write(ctxt, ctxt->memop.addr.mem, &fx_state, size);
+ return segmented_write_std(ctxt, ctxt->memop.addr.mem, &fx_state, size);
}
static int fxrstor_fixup(struct x86_emulate_ctxt *ctxt,
@@ -3974,7 +4016,7 @@ static int em_fxrstor(struct x86_emulate_ctxt *ctxt)
if (rc != X86EMUL_CONTINUE)
return rc;
- rc = segmented_read(ctxt, ctxt->memop.addr.mem, &fx_state, 512);
+ rc = segmented_read_std(ctxt, ctxt->memop.addr.mem, &fx_state, 512);
if (rc != X86EMUL_CONTINUE)
return rc;
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 5fe290c1b7d8..2f6ef5121a4c 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2426,3 +2426,9 @@ void kvm_lapic_init(void)
jump_label_rate_limit(&apic_hw_disabled, HZ);
jump_label_rate_limit(&apic_sw_disabled, HZ);
}
+
+void kvm_lapic_exit(void)
+{
+ static_key_deferred_flush(&apic_hw_disabled);
+ static_key_deferred_flush(&apic_sw_disabled);
+}
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index e0c80233b3e1..ff8039d61672 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -110,6 +110,7 @@ static inline bool kvm_hv_vapic_assist_page_enabled(struct kvm_vcpu *vcpu)
int kvm_lapic_enable_pv_eoi(struct kvm_vcpu *vcpu, u64 data);
void kvm_lapic_init(void);
+void kvm_lapic_exit(void);
#define VEC_POS(v) ((v) & (32 - 1))
#define REG_POS(v) (((v) >> 5) << 4)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2f22810a7e0c..57d8a856cdc5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3342,6 +3342,8 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
switch (cap->cap) {
case KVM_CAP_HYPERV_SYNIC:
+ if (!irqchip_in_kernel(vcpu->kvm))
+ return -EINVAL;
return kvm_hv_activate_synic(vcpu);
default:
return -EINVAL;
@@ -6045,6 +6047,7 @@ out:
void kvm_arch_exit(void)
{
+ kvm_lapic_exit();
perf_unregister_guest_info_callbacks(&kvm_guest_cbs);
if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC))
diff --git a/include/linux/jump_label_ratelimit.h b/include/linux/jump_label_ratelimit.h
index 089f70f83e97..23da3af459fe 100644
--- a/include/linux/jump_label_ratelimit.h
+++ b/include/linux/jump_label_ratelimit.h
@@ -14,6 +14,7 @@ struct static_key_deferred {
#ifdef HAVE_JUMP_LABEL
extern void static_key_slow_dec_deferred(struct static_key_deferred *key);
+extern void static_key_deferred_flush(struct static_key_deferred *key);
extern void
jump_label_rate_limit(struct static_key_deferred *key, unsigned long rl);
@@ -26,6 +27,10 @@ static inline void static_key_slow_dec_deferred(struct static_key_deferred *key)
STATIC_KEY_CHECK_USE();
static_key_slow_dec(&key->key);
}
+static inline void static_key_deferred_flush(struct static_key_deferred *key)
+{
+ STATIC_KEY_CHECK_USE();
+}
static inline void
jump_label_rate_limit(struct static_key_deferred *key,
unsigned long rl)
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 93ad6c1fb9b6..a9b8cf500591 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -182,6 +182,13 @@ void static_key_slow_dec_deferred(struct static_key_deferred *key)
}
EXPORT_SYMBOL_GPL(static_key_slow_dec_deferred);
+void static_key_deferred_flush(struct static_key_deferred *key)
+{
+ STATIC_KEY_CHECK_USE();
+ flush_delayed_work(&key->work);
+}
+EXPORT_SYMBOL_GPL(static_key_deferred_flush);
+
void jump_label_rate_limit(struct static_key_deferred *key,
unsigned long rl)
{
diff --git a/virt/lib/irqbypass.c b/virt/lib/irqbypass.c
index 52abac4bb6a2..6d2fcd6fcb25 100644
--- a/virt/lib/irqbypass.c
+++ b/virt/lib/irqbypass.c
@@ -195,7 +195,7 @@ int irq_bypass_register_consumer(struct irq_bypass_consumer *consumer)
mutex_lock(&lock);
list_for_each_entry(tmp, &consumers, node) {
- if (tmp->token == consumer->token) {
+ if (tmp->token == consumer->token || tmp == consumer) {
mutex_unlock(&lock);
module_put(THIS_MODULE);
return -EBUSY;
@@ -245,7 +245,7 @@ void irq_bypass_unregister_consumer(struct irq_bypass_consumer *consumer)
mutex_lock(&lock);
list_for_each_entry(tmp, &consumers, node) {
- if (tmp->token != consumer->token)
+ if (tmp != consumer)
continue;
list_for_each_entry(producer, &producers, node) {