Re: [PATCH v1 06/11] KVM: x86: use hardware-compatible format for APIC ID register

Paolo Bonzini
2016-07-01T08:36:25Z

On 30/06/2016 22:54, Radim Krčmář wrote:
> +static void __kvm_apic_state_fixup(struct kvm_vcpu *vcpu,
> + struct kvm_lapic_state *s, bool set)
> +{
> + if (apic_x2apic_mode(vcpu->arch.apic)) {
> + u32 *id = (u32 *)(s->regs + APIC_ID);
> + if (set)
> + *id >>= 24;
> + else
> + *id <<= 24;
> + }

When setting, this should read from the apic_base being set. So I think
you cannot use apic_x2apic_mode.

With this change, you don't need the struct kvm_vcpu argument now; add a
struct kvm argument instead in patch 10.

> @@ -2780,6 +2780,7 @@ static int kvm_vcpu_ioctl_get_lapic(struct kvm_vcpu *vcpu,
> kvm_x86_ops->sync_pir_to_irr(vcpu);
>
> memcpy(s->regs, vcpu->arch.apic->regs, sizeof *s);
> + kvm_apic_state_get_fixup(vcpu, s);

Instead of kvm_apic_state_get/set_fixup, group the memcpy and
__kvm_apic_state_fixup in a new function kvm_apic_get_state(struct
kvm_lapic *apic, char *regs).

> return 0;
> }
> @@ -2787,6 +2788,7 @@ static int kvm_vcpu_ioctl_get_lapic(struct kvm_vcpu *vcpu,
> static int kvm_vcpu_ioctl_set_lapic(struct kvm_vcpu *vcpu,
> struct kvm_lapic_state *s)
> {
> + kvm_apic_state_set_fixup(vcpu, s);
> kvm_apic_post_state_restore(vcpu, s);

... and likewise merge these two in a refactored
kvm_apic_post_state_restore called kvm_apic_set_state(struct kvm_lapic
*apic, char *regs), by calling __kvm_apic_state_fixup before
kvm_apic_post_state_restore's memcpy.

With these changes I guess there's no need for the underscores in
__kvm_apic_state_fixup. And you can also change the struct
kvm_lapic_state pointer in the function to a char *.

Thanks,

Paolo