From a20dde6f0b956aa5697da96f068625a5a75832dd Mon Sep 17 00:00:00 2001 From: "kaf24@firebug.cl.cam.ac.uk" Date: Thu, 20 Apr 2006 14:10:35 +0100 Subject: [PATCH] In both i386 and x86-64 Linux, using a static variable (and thus having the potential of missing synchronization there, as I suspect exists in native Linux) is not needed with the hypercall approach. In the hypervisor, the patch adds the needed synchronization. Signed-off-by: Jan Beulich --- .../arch/i386/kernel/io_apic-xen.c | 8 +++---- .../arch/x86_64/kernel/io_apic-xen.c | 8 +++---- xen/arch/x86/io_apic.c | 24 ++++++++++++++----- 3 files changed, 24 insertions(+), 16 deletions(-) diff --git a/linux-2.6-xen-sparse/arch/i386/kernel/io_apic-xen.c b/linux-2.6-xen-sparse/arch/i386/kernel/io_apic-xen.c index 47edb0524b..88a9f2f6f6 100644 --- a/linux-2.6-xen-sparse/arch/i386/kernel/io_apic-xen.c +++ b/linux-2.6-xen-sparse/arch/i386/kernel/io_apic-xen.c @@ -1205,7 +1205,6 @@ u8 irq_vector[NR_IRQ_VECTORS] __read_mostly; /* = { FIRST_DEVICE_VECTOR , 0 }; * int assign_irq_vector(int irq) { - static int current_vector = FIRST_DEVICE_VECTOR; physdev_op_t op; BUG_ON(irq >= NR_IRQ_VECTORS); @@ -1216,13 +1215,12 @@ int assign_irq_vector(int irq) op.u.irq_op.irq = irq; if (HYPERVISOR_physdev_op(&op)) return -ENOSPC; - current_vector = op.u.irq_op.vector; - vector_irq[current_vector] = irq; + vector_irq[op.u.irq_op.vector] = irq; if (irq != AUTO_ASSIGN) - IO_APIC_VECTOR(irq) = current_vector; + IO_APIC_VECTOR(irq) = op.u.irq_op.vector; - return current_vector; + return op.u.irq_op.vector; } #ifndef CONFIG_XEN diff --git a/linux-2.6-xen-sparse/arch/x86_64/kernel/io_apic-xen.c b/linux-2.6-xen-sparse/arch/x86_64/kernel/io_apic-xen.c index fd72947df7..d71120093e 100644 --- a/linux-2.6-xen-sparse/arch/x86_64/kernel/io_apic-xen.c +++ b/linux-2.6-xen-sparse/arch/x86_64/kernel/io_apic-xen.c @@ -869,7 +869,6 @@ u8 irq_vector[NR_IRQ_VECTORS] __read_mostly; int assign_irq_vector(int irq) { - static int current_vector = FIRST_DEVICE_VECTOR; physdev_op_t op; BUG_ON(irq != AUTO_ASSIGN && (unsigned)irq >= NR_IRQ_VECTORS); @@ -880,13 +879,12 @@ int assign_irq_vector(int irq) op.u.irq_op.irq = irq; if (HYPERVISOR_physdev_op(&op)) return -ENOSPC; - current_vector = op.u.irq_op.vector; - vector_irq[current_vector] = irq; + vector_irq[op.u.irq_op.vector] = irq; if (irq != AUTO_ASSIGN) - IO_APIC_VECTOR(irq) = current_vector; + IO_APIC_VECTOR(irq) = op.u.irq_op.vector; - return current_vector; + return op.u.irq_op.vector; } extern void (*interrupt[NR_IRQS])(void); diff --git a/xen/arch/x86/io_apic.c b/xen/arch/x86/io_apic.c index 4b7b1c5126..4d74e1900c 100644 --- a/xen/arch/x86/io_apic.c +++ b/xen/arch/x86/io_apic.c @@ -48,6 +48,7 @@ atomic_t irq_mis_count; static struct { int pin, apic; } ioapic_i8259 = { -1, -1 }; static DEFINE_SPINLOCK(ioapic_lock); +static DEFINE_SPINLOCK(vector_lock); int skip_ioapic_setup; @@ -661,11 +662,17 @@ u8 irq_vector[NR_IRQ_VECTORS] __read_mostly; int assign_irq_vector(int irq) { - static int current_vector = FIRST_DYNAMIC_VECTOR, offset = 0; + static unsigned current_vector = FIRST_DYNAMIC_VECTOR, offset = 0; + unsigned vector; BUG_ON(irq >= NR_IRQ_VECTORS); - if (irq != AUTO_ASSIGN && IO_APIC_VECTOR(irq) > 0) + spin_lock(&vector_lock); + + if (irq != AUTO_ASSIGN && IO_APIC_VECTOR(irq) > 0) { + spin_unlock(&vector_lock); return IO_APIC_VECTOR(irq); + } + next: current_vector += 8; @@ -679,16 +686,21 @@ next: if (current_vector > LAST_DYNAMIC_VECTOR) { offset++; - if (!(offset%8)) + if (!(offset%8)) { + spin_unlock(&vector_lock); return -ENOSPC; + } current_vector = FIRST_DYNAMIC_VECTOR + offset; } - vector_irq[current_vector] = irq; + vector = current_vector; + vector_irq[vector] = irq; if (irq != AUTO_ASSIGN) - IO_APIC_VECTOR(irq) = current_vector; + IO_APIC_VECTOR(irq) = vector; + + spin_unlock(&vector_lock); - return current_vector; + return vector; } static struct hw_interrupt_type ioapic_level_type; -- 2.30.2