x86/vpt: guarantee the return value of pt_update_irq() set in vIRR or PIR

pt_update_irq() is expected to return the vector number of periodic
timer interrupt, which should be set in vIRR of vlapic or in PIR.
Otherwise it would trigger the assertion in vmx_intr_assist(), please
seeing https://lists.xenproject.org/archives/html/xen-devel/2017-10/msg00915.html.

But it fails to achieve that in the following two case:
1. hvm_isa_irq_assert() may not set the corresponding bit in vIRR for
mask field of IOAPIC RTE is set. Please refer to the call tree
vmx_intr_assist() -> pt_update_irq() -> hvm_isa_irq_assert() ->
assert_irq() -> assert_gsi() -> vioapic_irq_positive_edge(). The patch
checks whether the vector is set or not in vIRR of vlapic or PIR before
returning.

2. someone changes the vector field of IOAPIC RTE between asserting
the irq and getting the vector of the irq, leading to setting the
old vector number but returning a different vector number. This patch
allows hvm_isa_irq_assert() to accept a callback which can get the
interrupt vector with irq_lock held. Thus, no one can change the vector
between the two operations.

BTW, the first argument of pi_test_and_set_pir() should be uint8_t
and I take this chance to fix it.

Signed-off-by: Chao Gao <chao.gao@intel.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Release-acked-by: Julien Grall <julien.grall@linaro.org>

diff --git a/xen/arch/x86/hvm/dm.c b/xen/arch/x86/hvm/dm.c
index 32ade9541da9edd7dead09ae6c2cf0a6369753ae..a787f43737ab80637c693d260f317a30a0c3a54c 100644 (file)
--- a/xen/arch/x86/hvm/dm.c
+++ b/xen/arch/x86/hvm/dm.c
@@ -143,7 +143,7 @@ static int set_isa_irq_level(struct domain *d, uint8_t isa_irq,
         hvm_isa_irq_deassert(d, isa_irq);
         break;
     case 1:
-        hvm_isa_irq_assert(d, isa_irq);
+        hvm_isa_irq_assert(d, isa_irq, NULL);
         break;
     default:
         return -EINVAL;

diff --git a/xen/arch/x86/hvm/irq.c b/xen/arch/x86/hvm/irq.c
index e425df913c6264ae30eb8fb4b881bea2490b9df0..0077f68a836ca984930d7487851bba264b010c53 100644 (file)
--- a/xen/arch/x86/hvm/irq.c
+++ b/xen/arch/x86/hvm/irq.c
@@ -168,11 +168,13 @@ void hvm_gsi_deassert(struct domain *d, unsigned int gsi)
     spin_unlock(&d->arch.hvm_domain.irq_lock);
 }
 
-void hvm_isa_irq_assert(
-    struct domain *d, unsigned int isa_irq)
+int hvm_isa_irq_assert(struct domain *d, unsigned int isa_irq,
+                       int (*get_vector)(const struct domain *d,
+                                         unsigned int gsi))
 {
     struct hvm_irq *hvm_irq = hvm_domain_irq(d);
     unsigned int gsi = hvm_isa_irq_to_gsi(isa_irq);
+    int vector = -1;
 
     ASSERT(isa_irq <= 15);
 
@@ -182,7 +184,12 @@ void hvm_isa_irq_assert(
          (hvm_irq->gsi_assert_count[gsi]++ == 0) )
         assert_irq(d, gsi, isa_irq);
 
+    if ( get_vector )
+        vector = get_vector(d, gsi);
+
     spin_unlock(&d->arch.hvm_domain.irq_lock);
+
+    return vector;
 }
 
 void hvm_isa_irq_deassert(

diff --git a/xen/arch/x86/hvm/pmtimer.c b/xen/arch/x86/hvm/pmtimer.c
index b70c299ed35505f2a0e62453fad1357213d768a1..435647ff1e594a64b676b3f659f8323a998add57 100644 (file)
--- a/xen/arch/x86/hvm/pmtimer.c
+++ b/xen/arch/x86/hvm/pmtimer.c
@@ -61,7 +61,7 @@ static void pmt_update_sci(PMTState *s)
     ASSERT(spin_is_locked(&s->lock));
 
     if ( acpi->pm1a_en & acpi->pm1a_sts & SCI_MASK )
-        hvm_isa_irq_assert(s->vcpu->domain, SCI_IRQ);
+        hvm_isa_irq_assert(s->vcpu->domain, SCI_IRQ, NULL);
     else
         hvm_isa_irq_deassert(s->vcpu->domain, SCI_IRQ);
 }

diff --git a/xen/arch/x86/hvm/rtc.c b/xen/arch/x86/hvm/rtc.c
index bcfa1693446f1f6f9f69ab0214f9a72288f83361..cb75b99ed11e7d79e749b57e6ff0b47972d414d6 100644 (file)
--- a/xen/arch/x86/hvm/rtc.c
+++ b/xen/arch/x86/hvm/rtc.c
@@ -75,7 +75,7 @@ static void rtc_update_irq(RTCState *s)
     s->hw.cmos_data[RTC_REG_C] |= RTC_IRQF;
     if ( rtc_mode_is(s, no_ack) )
         hvm_isa_irq_deassert(vrtc_domain(s), RTC_IRQ);
-    hvm_isa_irq_assert(vrtc_domain(s), RTC_IRQ);
+    hvm_isa_irq_assert(vrtc_domain(s), RTC_IRQ, NULL);
 }
 
 /* Called by the VPT code after it's injected a PF interrupt for us.

diff --git a/xen/arch/x86/hvm/vlapic.c b/xen/arch/x86/hvm/vlapic.c
index 4bfc53eab7dbbbeb83691118f850a279babceb7d..50f53bdaef5ab85bdbfeb9230419ed28f9c6da49 100644 (file)
--- a/xen/arch/x86/hvm/vlapic.c
+++ b/xen/arch/x86/hvm/vlapic.c
@@ -137,6 +137,18 @@ static void vlapic_error(struct vlapic *vlapic, unsigned int errmask)
     spin_unlock_irqrestore(&vlapic->esr_lock, flags);
 }
 
+bool vlapic_test_irq(const struct vlapic *vlapic, uint8_t vec)
+{
+    if ( unlikely(vec < 16) )
+        return false;
+
+    if ( hvm_funcs.test_pir &&
+         hvm_funcs.test_pir(const_vlapic_vcpu(vlapic), vec) )
+        return true;
+
+    return vlapic_test_vector(vec, &vlapic->regs->data[APIC_IRR]);
+}
+
 void vlapic_set_irq(struct vlapic *vlapic, uint8_t vec, uint8_t trig)
 {
     struct vcpu *target = vlapic_vcpu(vlapic);

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index c2148701eed94e949cfae5efa69d50149baae431..b18cceab55b2b793976d7c5f8cc6fdd9178e1a0a 100644 (file)
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -2125,6 +2125,11 @@ static void vmx_sync_pir_to_irr(struct vcpu *v)
         vlapic_set_vector(i, &vlapic->regs->data[APIC_IRR]);
 }
 
+static bool vmx_test_pir(const struct vcpu *v, uint8_t vec)
+{
+    return pi_test_pir(vec, &v->arch.hvm_vmx.pi_desc);
+}
+
 static void vmx_handle_eoi(u8 vector)
 {
     unsigned long status;
@@ -2352,6 +2357,7 @@ static struct hvm_function_table __initdata vmx_function_table = {
     .process_isr          = vmx_process_isr,
     .deliver_posted_intr  = vmx_deliver_posted_intr,
     .sync_pir_to_irr      = vmx_sync_pir_to_irr,
+    .test_pir             = vmx_test_pir,
     .handle_eoi           = vmx_handle_eoi,
     .nhvm_hap_walk_L1_p2m = nvmx_hap_walk_L1_p2m,
     .enable_msr_interception = vmx_enable_msr_interception,
@@ -2499,6 +2505,7 @@ const struct hvm_function_table * __init start_vmx(void)
     {
         vmx_function_table.deliver_posted_intr = NULL;
         vmx_function_table.sync_pir_to_irr = NULL;
+        vmx_function_table.test_pir = NULL;
     }
 
     if ( cpu_has_vmx_tsc_scaling )

diff --git a/xen/arch/x86/hvm/vpt.c b/xen/arch/x86/hvm/vpt.c
index 3841140be7711f597c5246fd9a0becbde1f66008..181f4cb6317c524767d1ed9dd47190122abb405d 100644 (file)
--- a/xen/arch/x86/hvm/vpt.c
+++ b/xen/arch/x86/hvm/vpt.c
@@ -252,7 +252,7 @@ int pt_update_irq(struct vcpu *v)
     struct list_head *head = &v->arch.hvm_vcpu.tm_list;
     struct periodic_time *pt, *temp, *earliest_pt;
     uint64_t max_lag;
-    int irq, is_lapic;
+    int irq, is_lapic, pt_vector;
 
     spin_lock(&v->arch.hvm_vcpu.tm_lock);
 
@@ -292,25 +292,38 @@ int pt_update_irq(struct vcpu *v)
 
     spin_unlock(&v->arch.hvm_vcpu.tm_lock);
 
+    /*
+     * If periodic timer interrut is handled by lapic, its vector in
+     * IRR is returned and used to set eoi_exit_bitmap for virtual
+     * interrupt delivery case. Otherwise return -1 to do nothing.
+     */
     if ( is_lapic )
+    {
         vlapic_set_irq(vcpu_vlapic(v), irq, 0);
+        pt_vector = irq;
+    }
     else
     {
         hvm_isa_irq_deassert(v->domain, irq);
-        hvm_isa_irq_assert(v->domain, irq);
+        if ( platform_legacy_irq(irq) && vlapic_accept_pic_intr(v) &&
+             v->domain->arch.hvm_domain.vpic[irq >> 3].int_output )
+        {
+            hvm_isa_irq_assert(v->domain, irq, NULL);
+            pt_vector = -1;
+        }
+        else
+        {
+            pt_vector = hvm_isa_irq_assert(v->domain, irq, vioapic_get_vector);
+            /*
+             * hvm_isa_irq_assert may not set the corresponding bit in vIRR
+             * when mask field of IOAPIC RTE is set. Check it again.
+             */
+            if ( pt_vector < 0 || !vlapic_test_irq(vcpu_vlapic(v), pt_vector) )
+                pt_vector = -1;
+        }
     }
 
-    /*
-     * If periodic timer interrut is handled by lapic, its vector in
-     * IRR is returned and used to set eoi_exit_bitmap for virtual
-     * interrupt delivery case. Otherwise return -1 to do nothing.  
-     */ 
-    if ( !is_lapic &&
-         platform_legacy_irq(irq) && vlapic_accept_pic_intr(v) &&
-         (&v->domain->arch.hvm_domain)->vpic[irq >> 3].int_output )
-        return -1;
-    else 
-        return pt_irq_vector(earliest_pt, hvm_intsrc_lapic);
+    return pt_vector;
 }
 
 static struct periodic_time *is_pt_irq(

diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
index b687e03dce8a1640587ce4803785b98b9c599de2..6ecad33316950abfe3383ce67550a358d1a7626d 100644 (file)
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -195,6 +195,7 @@ struct hvm_function_table {
     void (*process_isr)(int isr, struct vcpu *v);
     void (*deliver_posted_intr)(struct vcpu *v, u8 vector);
     void (*sync_pir_to_irr)(struct vcpu *v);
+    bool (*test_pir)(const struct vcpu *v, uint8_t vector);
     void (*handle_eoi)(u8 vector);
 
     /*Walk nested p2m  */

diff --git a/xen/include/asm-x86/hvm/irq.h b/xen/include/asm-x86/hvm/irq.h
index 3b6b4bd562ae5362a8e9f95fb1687c3e85d7c368..f756cb5a0d85d84de3c322d8d9adf9fcc07e6638 100644 (file)
--- a/xen/include/asm-x86/hvm/irq.h
+++ b/xen/include/asm-x86/hvm/irq.h
@@ -187,8 +187,16 @@ void hvm_pci_intx_assert(struct domain *d, unsigned int device,
 void hvm_pci_intx_deassert(struct domain *d, unsigned int device,
                            unsigned int intx);
 
-/* Modify state of an ISA device's IRQ wire. */
-void hvm_isa_irq_assert(struct domain *d, unsigned int isa_irq);
+/*
+ * Modify state of an ISA device's IRQ wire. For some cases, we are
+ * interested in the interrupt vector of the irq, but once the irq_lock
+ * is released, the vector may be changed by others. get_vector() callback
+ * allows us to get the interrupt vector in the protection of irq_lock.
+ * For most cases, just set get_vector to NULL.
+ */
+int hvm_isa_irq_assert(struct domain *d, unsigned int isa_irq,
+                       int (*get_vector)(const struct domain *d,
+                                         unsigned int gsi));
 void hvm_isa_irq_deassert(struct domain *d, unsigned int isa_irq);
 
 /* Modify state of GSIs. */

diff --git a/xen/include/asm-x86/hvm/vlapic.h b/xen/include/asm-x86/hvm/vlapic.h
index a63fcd56b863106f590bdbe6331ecba5c5f75c55..212c36b5c216a2b17315f8cafc81261f3e93a0c6 100644 (file)
--- a/xen/include/asm-x86/hvm/vlapic.h
+++ b/xen/include/asm-x86/hvm/vlapic.h
@@ -110,6 +110,7 @@ static inline void vlapic_set_reg(
 
 bool_t is_vlapic_lvtpc_enabled(struct vlapic *vlapic);
 
+bool vlapic_test_irq(const struct vlapic *vlapic, uint8_t vec);
 void vlapic_set_irq(struct vlapic *vlapic, uint8_t vec, uint8_t trig);
 
 int vlapic_has_pending_irq(struct vcpu *v);

diff --git a/xen/include/asm-x86/hvm/vmx/vmx.h b/xen/include/asm-x86/hvm/vmx/vmx.h
index 4889a64255d412d380bb4544c8892b3600e3cbe2..7341cb191ef28ef3139a24e35652c10bd117f12e 100644 (file)
--- a/xen/include/asm-x86/hvm/vmx/vmx.h
+++ b/xen/include/asm-x86/hvm/vmx/vmx.h
@@ -104,11 +104,16 @@ void vmx_update_secondary_exec_control(struct vcpu *v);
 
 #define POSTED_INTR_ON  0
 #define POSTED_INTR_SN  1
-static inline int pi_test_and_set_pir(int vector, struct pi_desc *pi_desc)
+static inline int pi_test_and_set_pir(uint8_t vector, struct pi_desc *pi_desc)
 {
     return test_and_set_bit(vector, pi_desc->pir);
 }
 
+static inline int pi_test_pir(uint8_t vector, const struct pi_desc *pi_desc)
+{
+    return test_bit(vector, pi_desc->pir);
+}
+
 static inline int pi_test_and_set_on(struct pi_desc *pi_desc)
 {
     return test_and_set_bit(POSTED_INTR_ON, &pi_desc->control);