# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID f84a333d8aa6e1a25e2b73b07610e95007267f6a
# Parent 05db1d61e031d2fb48e561b185fa42981547db9a
Robustify and add tracing to the IO-APIC update hypercall.
If this patch, and any others that follow it, fix some of the
prblems that various users have been seeing then they may
be good candidates for backporting to 3.0.2 (assuming no
regressions for other users).
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
diff -r 05db1d61e031 -r f84a333d8aa6 xen/arch/x86/io_apic.c
--- a/xen/arch/x86/io_apic.c Fri Apr 7 15:15:44 2006
+++ b/xen/arch/x86/io_apic.c Fri Apr 7 17:41:28 2006
@@ -75,6 +75,7 @@
static struct irq_pin_list {
int apic, pin, next;
} irq_2_pin[PIN_MAP_SIZE];
+static int irq_2_pin_free_entry = NR_IRQS;
int vector_irq[NR_VECTORS] __read_mostly = { [0 ... NR_VECTORS - 1] = -1};
@@ -85,20 +86,52 @@
*/
static void add_pin_to_irq(unsigned int irq, int apic, int pin)
{
- static int first_free_entry = NR_IRQS;
struct irq_pin_list *entry = irq_2_pin + irq;
- while (entry->next)
+ while (entry->next) {
+ BUG_ON((entry->apic == apic) && (entry->pin == pin));
entry = irq_2_pin + entry->next;
+ }
+
+ BUG_ON((entry->apic == apic) && (entry->pin == pin));
if (entry->pin != -1) {
- entry->next = first_free_entry;
+ if (irq_2_pin_free_entry >= PIN_MAP_SIZE)
+ panic("io_apic.c: whoops");
+ entry->next = irq_2_pin_free_entry;
entry = irq_2_pin + entry->next;
- if (++first_free_entry >= PIN_MAP_SIZE)
- panic("io_apic.c: whoops");
+ irq_2_pin_free_entry = entry->next;
+ entry->next = 0;
}
entry->apic = apic;
entry->pin = pin;
+}
+
+static void remove_pin_at_irq(unsigned int irq, int apic, int pin)
+{
+ struct irq_pin_list *entry, *prev;
+ int idx;
+
+ for (entry = &irq_2_pin[irq]; ; entry = &irq_2_pin[entry->next]) {
+ if ((entry->apic == apic) && (entry->pin == pin))
+ break;
+ if (!entry->next)
+ BUG();
+ }
+
+ entry->pin = -1;
+ entry->apic = -1;
+
+ idx = entry - irq_2_pin;
+ if (idx >= NR_IRQS) {
+ while (prev->next != idx)
+ prev = &irq_2_pin[prev->next];
+ prev->next = entry->next;
+ entry->next = irq_2_pin_free_entry;
+ irq_2_pin_free_entry = idx;
+ } else {
+ entry->next = 0;
+ }
}
/*
@@ -958,6 +991,10 @@
irq_2_pin[i].pin = -1;
irq_2_pin[i].next = 0;
}
+
+ /* Initialise dynamic irq_2_pin free list. */
+ for (i = NR_IRQS; i < PIN_MAP_SIZE; i++)
+ irq_2_pin[i].next = i + 1;
/*
* The number of IO-APIC IRQ registers (== #pins):
@@ -1854,11 +1891,18 @@
return 0;
}
+#define WARN_BOGUS_WRITE(f, a...) \
+ printk("%s: apic=%d,pin=%d,oirq=%d,nirq=%d\n" \
+ "%s: oent=%08x:%08x,nent=%08x:%08x\n" \
+ "%s: " f, __FUNCTION__, apic, pin, old_irq, new_irq, \
+ __FUNCTION__, *(u32 *)&old_rte, *((u32 *)&old_rte+1), \
+ *(u32 *)&new_rte, *((u32 *)&new_rte+1), \
+ __FUNCTION__ , ##a )
+
int ioapic_guest_write(unsigned long physbase, unsigned int reg, u32 val)
{
- int apic, pin, irq;
- struct IO_APIC_route_entry rte = { 0 };
- struct irq_pin_list *entry;
+ int apic, pin, old_irq = -1, new_irq = -1;
+ struct IO_APIC_route_entry old_rte = { 0 }, new_rte = { 0 };
unsigned long flags;
if ( (apic = ioapic_physbase_to_id(physbase)) < 0 )
@@ -1870,8 +1914,9 @@
pin = (reg - 0x10) >> 1;
- *(u32 *)&rte = val;
- rte.dest.logical.logical_dest = cpu_mask_to_apicid(TARGET_CPUS);
+ /* Write first half from guest; second half is target info. */
+ *(u32 *)&new_rte = val;
+ new_rte.dest.logical.logical_dest = cpu_mask_to_apicid(TARGET_CPUS);
/*
* What about weird destination types?
@@ -1881,7 +1926,7 @@
* ExtINT: Ignore? Linux only asserts this at start of day.
* For now, print a message and return an error. We can fix up on demand.
*/
- if ( rte.delivery_mode > dest_LowestPrio )
+ if ( new_rte.delivery_mode > dest_LowestPrio )
{
printk("ERROR: Attempt to write weird IOAPIC destination mode!\n");
printk(" APIC=%d/%d, lo-reg=%x\n", apic, pin, val);
@@ -1892,36 +1937,69 @@
* The guest does not know physical APIC arrangement (flat vs. cluster).
* Apply genapic conventions for this platform.
*/
- rte.delivery_mode = INT_DELIVERY_MODE;
- rte.dest_mode = INT_DEST_MODE;
-
- if ( rte.vector >= FIRST_DEVICE_VECTOR )
- {
- /* Is there a valid irq mapped to this vector? */
- irq = vector_irq[rte.vector];
- if ( !IO_APIC_IRQ(irq) )
+ new_rte.delivery_mode = INT_DELIVERY_MODE;
+ new_rte.dest_mode = INT_DEST_MODE;
+
+ spin_lock_irqsave(&ioapic_lock, flags);
+
+ /* Read first (interesting) half of current routing entry. */
+ *(u32 *)&old_rte = io_apic_read(apic, 0x10 + 2 * pin);
+
+ /* No change to the first half of the routing entry? Bail quietly. */
+ if ( *(u32 *)&old_rte == *(u32 *)&new_rte )
+ {
+ spin_unlock_irqrestore(&ioapic_lock, flags);
+ return 0;
+ }
+
+ if ( old_rte.vector >= FIRST_DEVICE_VECTOR )
+ old_irq = vector_irq[old_rte.vector];
+ if ( new_rte.vector >= FIRST_DEVICE_VECTOR )
+ new_irq = vector_irq[new_rte.vector];
+
+ if ( (old_irq != new_irq) && (old_irq != -1) && IO_APIC_IRQ(old_irq) )
+ {
+ if ( irq_desc[IO_APIC_VECTOR(old_irq)].action )
+ {
+ WARN_BOGUS_WRITE("Attempt to remove IO-APIC pin of in-use IRQ!\n");
+ spin_unlock_irqrestore(&ioapic_lock, flags);
return 0;
-
+ }
+
+ remove_pin_at_irq(old_irq, apic, pin);
+ }
+
+ if ( (new_irq != -1) && IO_APIC_IRQ(new_irq) )
+ {
+ if ( irq_desc[IO_APIC_VECTOR(new_irq)].action )
+ {
+ WARN_BOGUS_WRITE("Attempt to %s IO-APIC pin for in-use IRQ!\n",
+ (old_irq != new_irq) ? "add" : "modify");
+ spin_unlock_irqrestore(&ioapic_lock, flags);
+ return 0;
+ }
+
/* Set the correct irq-handling type. */
- irq_desc[IO_APIC_VECTOR(irq)].handler = rte.trigger ?
+ irq_desc[IO_APIC_VECTOR(new_irq)].handler = new_rte.trigger ?
&ioapic_level_type: &ioapic_edge_type;
-
- /* Record the pin<->irq mapping. */
- for ( entry = &irq_2_pin[irq]; ; entry = &irq_2_pin[entry->next] )
- {
- if ( (entry->apic == apic) && (entry->pin == pin) )
- break;
- if ( !entry->next )
- {
- add_pin_to_irq(irq, apic, pin);
- break;
- }
- }
- }
-
- spin_lock_irqsave(&ioapic_lock, flags);
- io_apic_write(apic, 0x10 + 2 * pin, *(((int *)&rte) + 0));
- io_apic_write(apic, 0x11 + 2 * pin, *(((int *)&rte) + 1));
+
+ if ( old_irq != new_irq )
+ add_pin_to_irq(new_irq, apic, pin);
+
+ /* Mask iff level triggered. */
+ new_rte.mask = new_rte.trigger;
+ }
+ else if ( !new_rte.mask )
+ {
+ /* This pin leads nowhere but the guest has not masked it. */
+ WARN_BOGUS_WRITE("Installing bogus unmasked IO-APIC entry!\n");
+ new_rte.mask = 1;
+ }
+
+
+ io_apic_write(apic, 0x10 + 2 * pin, *(((int *)&new_rte) + 0));
+ io_apic_write(apic, 0x11 + 2 * pin, *(((int *)&new_rte) + 1));
+
spin_unlock_irqrestore(&ioapic_lock, flags);
return 0;
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