From c5746b021e573184fb92b601a0e93a295485054e Mon Sep 17 00:00:00 2001 From: Matthew Barnes Date: Thu, 20 Jun 2024 16:36:46 +0100 Subject: [PATCH] x86/ioapic: Fix signed shifts in io_apic.c There exists bitshifts in the IOAPIC code where signed integers are shifted to the left by up to 31 bits, which is undefined behaviour. This patch fixes this by changing the integers from signed to unsigned. Signed-off-by: Matthew Barnes Reviewed-by: Jan Beulich Reviewed-by: Andrew Cooper Release-Acked-By: Oleksii Kurochko --- xen/arch/x86/io_apic.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/xen/arch/x86/io_apic.c b/xen/arch/x86/io_apic.c index b48a64246548..d73108558e09 100644 --- a/xen/arch/x86/io_apic.c +++ b/xen/arch/x86/io_apic.c @@ -1692,7 +1692,8 @@ static void cf_check mask_and_ack_level_ioapic_irq(struct irq_desc *desc) !io_apic_level_ack_pending(desc->irq)) move_masked_irq(desc); - if ( !(v & (1 << (i & 0x1f))) ) { + if ( !(v & (1U << (i & 0x1f))) ) + { spin_lock(&ioapic_lock); __edge_IO_APIC_irq(desc->irq); __level_IO_APIC_irq(desc->irq); @@ -1756,7 +1757,8 @@ static void cf_check end_level_ioapic_irq_new(struct irq_desc *desc, u8 vector) !io_apic_level_ack_pending(desc->irq) ) move_native_irq(desc); - if (!(v & (1 << (i & 0x1f)))) { + if ( !(v & (1U << (i & 0x1f))) ) + { spin_lock(&ioapic_lock); __mask_IO_APIC_irq(desc->irq); __edge_IO_APIC_irq(desc->irq);