Hi Sasha,
On 12/12/11 06:50, Sasha Levin wrote:
> Just set delivery mode directly without going through ugly casting.
>
> This cleans up and simplifies the code.
>
> Signed-off-by: Sasha Levin <[email protected]>
> ---
> tools/kvm/x86/kvm-cpu.c | 10 ++--------
> 1 files changed, 2 insertions(+), 8 deletions(-)
>
> diff --git a/tools/kvm/x86/kvm-cpu.c b/tools/kvm/x86/kvm-cpu.c
> index 27b7a8f..cc1f560 100644
> --- a/tools/kvm/x86/kvm-cpu.c
> +++ b/tools/kvm/x86/kvm-cpu.c
> @@ -81,18 +81,12 @@ static int kvm_cpu__set_lint(struct kvm_cpu *vcpu)
> {
> struct kvm_lapic_state klapic;
> struct local_apic *lapic = (void *)&klapic;
> - u32 lvt;
>
> if (ioctl(vcpu->vcpu_fd, KVM_GET_LAPIC, &klapic))
> return -1;
>
> - lvt = *(u32 *)&lapic->lvt_lint0;
> - lvt = SET_APIC_DELIVERY_MODE(lvt, APIC_MODE_EXTINT);
> - *(u32 *)&lapic->lvt_lint0 = lvt;
> -
> - lvt = *(u32 *)&lapic->lvt_lint1;
> - lvt = SET_APIC_DELIVERY_MODE(lvt, APIC_MODE_NMI);
> - *(u32 *)&lapic->lvt_lint1 = lvt;
> + lapic->lvt_lint0.delivery_mode = APIC_MODE_EXTINT;
> + lapic->lvt_lint1.delivery_mode = APIC_MODE_NMI;
>
> return ioctl(vcpu->vcpu_fd, KVM_SET_LAPIC, &klapic);
> }
I'm getting this on x86-32, gcc 4.4.3:
CC x86/kvm-cpu.o
cc1: warnings being treated as errors
x86/kvm-cpu.c: In function ‘kvm_cpu__set_lint’:
x86/kvm-cpu.c:89: error: dereferencing pointer ‘lapic’ does break
strict-aliasing rules
x86/kvm-cpu.c:88: error: dereferencing pointer ‘lapic’ does break
strict-aliasing rules
x86/kvm-cpu.c:83: note: initialized from here
make: *** [x86/kvm-cpu.o] Error 1
Removing the nasty aliasing (patch below) seems to be a good way to go. What do
you think?
Cheers,
Matt
---
diff --git a/tools/kvm/x86/kvm-cpu.c b/tools/kvm/x86/kvm-cpu.c
index cc1f560..30f1ad6 100644
--- a/tools/kvm/x86/kvm-cpu.c
+++ b/tools/kvm/x86/kvm-cpu.c
@@ -79,16 +79,15 @@ void kvm_cpu__delete(struct kvm_cpu *vcpu)
static int kvm_cpu__set_lint(struct kvm_cpu *vcpu)
{
- struct kvm_lapic_state klapic;
- struct local_apic *lapic = (void *)&klapic;
+ struct local_apic lapic;
- if (ioctl(vcpu->vcpu_fd, KVM_GET_LAPIC, &klapic))
+ if (ioctl(vcpu->vcpu_fd, KVM_GET_LAPIC, &lapic))
return -1;
- lapic->lvt_lint0.delivery_mode = APIC_MODE_EXTINT;
- lapic->lvt_lint1.delivery_mode = APIC_MODE_NMI;
+ lapic.lvt_lint0.delivery_mode = APIC_MODE_EXTINT;
+ lapic.lvt_lint1.delivery_mode = APIC_MODE_NMI;
- return ioctl(vcpu->vcpu_fd, KVM_SET_LAPIC, &klapic);
+ return ioctl(vcpu->vcpu_fd, KVM_SET_LAPIC, &lapic);
}
struct kvm_cpu *kvm_cpu__init(struct kvm *kvm, unsigned long cpu_id)
--
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