On Mon, May 25, 2009 at 05:46:22PM -0300, Marcelo Tosatti wrote:
> On Mon, May 25, 2009 at 06:50:33PM +0300, Gleb Natapov wrote:
> > Use it instead of open code "vcpu_id zero is BSP" assumption.
> >
> > Signed-off-by: Gleb Natapov <gleb@xxxxxxxxxx>
> > ---
> > arch/ia64/kvm/kvm-ia64.c | 2 +-
> > arch/ia64/kvm/vcpu.c | 2 +-
> > arch/x86/kvm/i8254.c | 4 ++--
> > arch/x86/kvm/i8259.c | 6 +++---
> > arch/x86/kvm/lapic.c | 7 ++++---
> > arch/x86/kvm/svm.c | 4 ++--
> > arch/x86/kvm/vmx.c | 6 +++---
> > arch/x86/kvm/x86.c | 4 ++--
> > include/linux/kvm_host.h | 5 +++++
> > virt/kvm/ioapic.c | 4 +++-
> > virt/kvm/kvm_main.c | 2 ++
> > 11 files changed, 28 insertions(+), 18 deletions(-)
> >
> > #endif
> > diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
> > index 1eddae9..a8a8252 100644
> > --- a/virt/kvm/ioapic.c
> > +++ b/virt/kvm/ioapic.c
> > @@ -165,7 +165,9 @@ static int ioapic_deliver(struct kvm_ioapic *ioapic, int irq)
> > /* Always delivery PIT interrupt to vcpu 0 */
> > if (irq == 0) {
> > irqe.dest_mode = 0; /* Physical mode. */
> > - irqe.dest_id = ioapic->kvm->vcpus[0]->vcpu_id;
> > + /* need to read apic_id from apic regiest since
> > + * it can be rewritten */
> > + irqe.dest_id = ioapic->kvm->bsp_vcpu->vcpu_id;
> > }
>
> Won't this oops if userspace creates only vcpu 3 and attempts to deliver
> to IRQ0 ? (not directly related to the patchset though).
I doesn't oops since if BSP is not created this code is not reached
(nothing runs eventually). But see below.
>
> Also you said "The code still assumes that boot cpu is created first."
> Where is that?
>
Oops. It should be like this, but this patch series has a bug. In
kvm_vm_ioctl_create_vcpu:
if (id == 0)
kvm->bsp_vcpu = vcpu;
should be:
if (!kvm->bsp_vcpu)
kvm->bsp_vcpu = vcpu;
I really don't want to make acpi_id zero to be special.
> Otherwise, neat!
>
> > #endif
> > return kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe);
> > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> > index de042cb..5a55fe0 100644
> > --- a/virt/kvm/kvm_main.c
> > +++ b/virt/kvm/kvm_main.c
> > @@ -1737,6 +1737,8 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, int n)
> > goto vcpu_destroy;
> > }
> > kvm->vcpus[n] = vcpu;
> > + if (n == 0)
> > + kvm->bsp_vcpu = vcpu;
> > mutex_unlock(&kvm->lock);
> >
> > /* Now it's all set up, let userspace reach it */
> > --
> > 1.6.2.1
> >
> > --
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--
Gleb.
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