On 09.01.2024 16:38, Alejandro Vallejo wrote:
> --- a/xen/arch/x86/domain.c
> +++ b/xen/arch/x86/domain.c
> @@ -288,7 +288,10 @@ void update_guest_memory_policy(struct vcpu *v,
> static void cpu_policy_updated(struct vcpu *v)
> {
> if ( is_hvm_vcpu(v) )
> + {
> hvm_cpuid_policy_changed(v);
> + vlapic_cpu_policy_changed(v);
> + }
> }
This is a layering violation imo; hvm_cpuid_policy_changed() wants
to call vlapic_cpu_policy_changed().
> @@ -1083,6 +1083,22 @@ static void set_x2apic_id(struct vlapic *vlapic)
> vlapic_set_reg(vlapic, APIC_LDR, apic_ldr);
> }
>
> +void vlapic_cpu_policy_changed(struct vcpu *v)
> +{
> + struct vlapic *vlapic = vcpu_vlapic(v);
> + struct cpu_policy *cp = v->domain->arch.cpu_policy;
const please
> @@ -1514,6 +1530,13 @@ static void lapic_load_fixup(struct vlapic *vlapic)
> const struct vcpu *v = vlapic_vcpu(vlapic);
> uint32_t good_ldr = x2apic_ldr_from_id(vlapic->loaded.id);
>
> + /*
> + * Guest with hardcoded assumptions about x2apic_id <-> vcpu_id
> + * mappings. Recreate the mapping it used to have in old host.
> + */
> + if ( !vlapic->hw.x2apic_id )
> + vlapic->hw.x2apic_id = v->vcpu_id * 2;
This looks to depend upon it only ever being vCPU which may get a (new
style) APIC ID of 0. I think such at least wants mentioning in the
comment.
> --- a/xen/include/public/arch-x86/hvm/save.h
> +++ b/xen/include/public/arch-x86/hvm/save.h
> @@ -394,6 +394,8 @@ struct hvm_hw_lapic {
> uint32_t disabled; /* VLAPIC_xx_DISABLED */
> uint32_t timer_divisor;
> uint64_t tdt_msr;
> + uint32_t x2apic_id;
> + uint32_t rsvd_zero;
> };
I can't spot any checking of this last field indeed being zero.
Jan
