diff options
| -rw-r--r-- | include/kvm/arm_vgic.h | 3 | ||||
| -rw-r--r-- | virt/kvm/arm/vgic/vgic-mmio-v2.c | 16 |
2 files changed, 18 insertions, 1 deletions
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h index c661d0ee6628..c134790be32c 100644 --- a/include/kvm/arm_vgic.h +++ b/include/kvm/arm_vgic.h @@ -221,6 +221,9 @@ struct vgic_dist { /* Implementation revision as reported in the GICD_IIDR */ u32 implementation_rev; + /* Userspace can write to GICv2 IGROUPR */ + bool v2_groups_user_writable; + /* Do injected MSIs require an additional device ID? */ bool msis_require_devid; diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c index ee164f831401..26654f4140ed 100644 --- a/virt/kvm/arm/vgic/vgic-mmio-v2.c +++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c @@ -85,6 +85,18 @@ static int vgic_mmio_uaccess_write_v2_misc(struct kvm_vcpu *vcpu, case GIC_DIST_IIDR: if (val != vgic_mmio_read_v2_misc(vcpu, addr, len)) return -EINVAL; + + /* + * If we observe a write to GICD_IIDR we know that userspace + * has been updated and has had a chance to cope with older + * kernels (VGICv2 IIDR.Revision == 0) incorrectly reporting + * interrupts as group 1, and therefore we now allow groups to + * be user writable. Doing this by default would break + * migration from old kernels to new kernels with legacy + * userspace. + */ + vcpu->kvm->arch.vgic.v2_groups_user_writable = true; + return 0; } vgic_mmio_write_v2_misc(vcpu, addr, len, val); @@ -95,7 +107,9 @@ static int vgic_mmio_uaccess_write_v2_group(struct kvm_vcpu *vcpu, gpa_t addr, unsigned int len, unsigned long val) { - /* Ignore writes from userspace */ + if (vcpu->kvm->arch.vgic.v2_groups_user_writable) + vgic_mmio_write_group(vcpu, addr, len, val); + return 0; } |