[Xen-changelog] [xen-unstable] [HVM] A few cleanups to i8259.c -- in particular change

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID 047669f57e5c1bb7902f55c63dc61eebf7f4a67e
# Parent  fb2751668a4dd2dea5f09f0c9df87001b1505634
[HVM] A few cleanups to i8259.c -- in particular change
ELCR semantics (should not be modified by PIC reset).

This effectively removes Steve Smith's changeset
11586:08a582a98471da30fb86bca620495f3d91d55800
but the real bug here is not that the ELCR was reset to
zero, but that it was touched at all.

Our BIOS code should set the ELCR correctly (level-triggered)
for PCI IRQs.

Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
---
 xen/arch/x86/hvm/i8259.c |   49 +++++++++++++++--------------------------------
 1 files changed, 16 insertions(+), 33 deletions(-)

diff -r fb2751668a4d -r 047669f57e5c xen/arch/x86/hvm/i8259.c
--- a/xen/arch/x86/hvm/i8259.c  Fri Sep 22 20:20:57 2006 +0100
+++ b/xen/arch/x86/hvm/i8259.c  Sat Sep 23 12:39:18 2006 +0100
@@ -35,12 +35,11 @@
 #include <asm/current.h>
 
 /* set irq level. If an edge is detected, then the IRR is set to 1 */
-/* Caller must hold vpic lock */
 static inline void pic_set_irq1(PicState *s, int irq, int level)
 {
     int mask;
 
-    BUG_ON(!spin_is_locked(&s->pics_state->lock));
+    ASSERT(spin_is_locked(&s->pics_state->lock));
 
     mask = 1 << irq;
     if (s->elcr & mask) {
@@ -55,9 +54,8 @@ static inline void pic_set_irq1(PicState
     } else {
         /* edge triggered */
         if (level) {
-            if ((s->last_irr & mask) == 0) {
+            if ((s->last_irr & mask) == 0)
                 s->irr |= mask;
-            }
             s->last_irr |= mask;
         } else {
             s->last_irr &= ~mask;
@@ -67,12 +65,11 @@ static inline void pic_set_irq1(PicState
 
 /* return the highest priority found in mask (highest = smallest
    number). Return 8 if no irq */
-/* Caller must hold vpic lock */
 static inline int get_priority(PicState *s, int mask)
 {
     int priority;
 
-    BUG_ON(!spin_is_locked(&s->pics_state->lock));
+    ASSERT(spin_is_locked(&s->pics_state->lock));
 
     if (mask == 0)
         return 8;
@@ -83,12 +80,11 @@ static inline int get_priority(PicState 
 }
 
 /* return the pic wanted interrupt. return -1 if none */
-/* Caller must hold vpic lock */
 static int pic_get_irq(PicState *s)
 {
     int mask, cur_priority, priority;
 
-    BUG_ON(!spin_is_locked(&s->pics_state->lock));
+    ASSERT(spin_is_locked(&s->pics_state->lock));
 
     mask = s->irr & ~s->imr;
     priority = get_priority(s, mask);
@@ -112,12 +108,11 @@ static int pic_get_irq(PicState *s)
 /* raise irq to CPU if necessary. must be called every time the active
    irq may change */
 /* XXX: should not export it, but it is needed for an APIC kludge */
-/* Caller must hold vpic lock */
 void pic_update_irq(struct hvm_virpic *s)
 {
     int irq2, irq;
 
-    BUG_ON(!spin_is_locked(&s->lock));
+    ASSERT(spin_is_locked(&s->lock));
 
     /* first look at slave pic */
     irq2 = pic_get_irq(&s->pics[1]);
@@ -179,10 +174,9 @@ void pic_set_irq(struct hvm_virpic *isa_
 }
 
 /* acknowledge interrupt 'irq' */
-/* Caller must hold vpic lock */
 static inline void pic_intack(PicState *s, int irq)
 {
-    BUG_ON(!spin_is_locked(&s->pics_state->lock));
+    ASSERT(spin_is_locked(&s->pics_state->lock));
 
     if (s->auto_eoi) {
         if (s->rotate_on_auto_eoi)
@@ -219,7 +213,6 @@ int pic_read_irq(struct hvm_virpic *s)
         }
     } else {
         /* spurious IRQ on host controller */
-        printk("spurious IRQ irq got=%d\n",irq);
         irq = 7;
         intno = s->pics[0].irq_base + irq;
     }
@@ -229,12 +222,11 @@ int pic_read_irq(struct hvm_virpic *s)
     return intno;
 }
 
-/* Caller must hold vpic lock */
 static void update_shared_irr(struct hvm_virpic *s, PicState *c)
 {
     uint8_t *pl, *pe;
 
-    BUG_ON(!spin_is_locked(&s->lock));
+    ASSERT(spin_is_locked(&s->lock));
 
     get_sp(current->domain)->sp_global.pic_elcr = 
         s->pics[0].elcr | ((u16)s->pics[1].elcr << 8);
@@ -250,12 +242,11 @@ static void update_shared_irr(struct hvm
     }
 }
 
-/* Caller must hold vpic lock */
 static void pic_reset(void *opaque)
 {
     PicState *s = opaque;
 
-    BUG_ON(!spin_is_locked(&s->pics_state->lock));
+    ASSERT(spin_is_locked(&s->pics_state->lock));
 
     s->last_irr = 0;
     s->irr = 0;
@@ -271,19 +262,15 @@ static void pic_reset(void *opaque)
     s->rotate_on_auto_eoi = 0;
     s->special_fully_nested_mode = 0;
     s->init4 = 0;
-
-    /* Initialise to level triggered mode, since Linux assumes that in
-       a few places and it doesn't appear to break anything. */
-    s->elcr = 0xff & s->elcr_mask;
-}
-
-/* Caller must hold vpic lock */
+    /* Note: ELCR is not reset */
+}
+
 static void pic_ioport_write(void *opaque, uint32_t addr, uint32_t val)
 {
     PicState *s = opaque;
     int priority, cmd, irq;
 
-    BUG_ON(!spin_is_locked(&s->pics_state->lock));
+    ASSERT(spin_is_locked(&s->pics_state->lock));
 
     addr &= 1;
     if (addr == 0) {
@@ -371,12 +358,11 @@ static void pic_ioport_write(void *opaqu
     }
 }
 
-/* Caller must hold vpic lock */
 static uint32_t pic_poll_read (PicState *s, uint32_t addr1)
 {
     int ret;
 
-    BUG_ON(!spin_is_locked(&s->pics_state->lock));
+    ASSERT(spin_is_locked(&s->pics_state->lock));
 
     ret = pic_get_irq(s);
     if (ret >= 0) {
@@ -396,14 +382,13 @@ static uint32_t pic_poll_read (PicState 
     return ret;
 }
 
-/* Caller must hold vpic lock */
 static uint32_t pic_ioport_read(void *opaque, uint32_t addr1)
 {
     PicState *s = opaque;
     unsigned int addr;
     int ret;
 
-    BUG_ON(!spin_is_locked(&s->pics_state->lock));
+    ASSERT(spin_is_locked(&s->pics_state->lock));
 
     addr = addr1;
     addr &= 1;
@@ -442,11 +427,10 @@ uint32_t pic_intack_read(struct hvm_virp
 }
 
 static void elcr_ioport_write(void *opaque, uint32_t addr, uint32_t val)
-/* Caller must hold vpic lock */
 {
     PicState *s = opaque;
 
-    BUG_ON(!spin_is_locked(&s->pics_state->lock));
+    ASSERT(spin_is_locked(&s->pics_state->lock));
 
     s->elcr = val & s->elcr_mask;
 }
@@ -458,10 +442,9 @@ static uint32_t elcr_ioport_read(void *o
 }
 
 /* XXX: add generic master/slave system */
-/* Caller must hold vpic lock */
 static void pic_init1(int io_addr, int elcr_addr, PicState *s)
 {
-    BUG_ON(!spin_is_locked(&s->pics_state->lock));
+    ASSERT(spin_is_locked(&s->pics_state->lock));
 
     pic_reset(s);
 }

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