On Wed, 2 Jul 2025 at 17:31, Eric Auger <eric.au...@redhat.com> wrote:
>
> From: Haibo Xu <haibo...@linaro.org>
>
> Allow virt arm machine to set the interrupt ID for the KVM
> GIC maintenance interrupt.
>
> This setting must be done before the KVM_DEV_ARM_VGIC_CTRL_INIT
> hence the choice to perform the setting in the GICv3 realize
> instead of proceeding the same way as kvm_arm_pmu_set_irq().
>
> Signed-off-by: Haibo Xu <haibo...@linaro.org>
> Signed-off-by: Miguel Luis <miguel.l...@oracle.com>
> Signed-off-by: Eric Auger <eric.au...@redhat.com>
> @@ -231,6 +231,7 @@ struct GICv3State {
> uint32_t num_cpu;
> uint32_t num_irq;
> uint32_t revision;
> + uint32_t maint_irq;
> bool lpi_enable;
> bool nmi_support;
> bool security_extn;
> + if (s->maint_irq) {
> + int ret;
> +
> + ret = kvm_device_check_attr(s->dev_fd,
> + KVM_DEV_ARM_VGIC_GRP_MAINT_IRQ, 0);
> + if (!ret) {
> + error_setg_errno(errp, errno,
> + "VGICv3 setting maintenance IRQ is not "
> + "supported by this host kernel");
> + return;
> + }
> +
> + ret = kvm_device_access(s->dev_fd, KVM_DEV_ARM_VGIC_GRP_MAINT_IRQ, 0,
> + &s->maint_irq, true, errp);
This doesn't seem to line up with what the kernel documents
for KVM_DEV_ARM_VGIC_GRP_MAINT_IRQ:
https://www.kernel.org/doc/Documentation/virt/kvm/devices/arm-vgic-v3.rst
says
# KVM_DEV_ARM_VGIC_GRP_MAINT_IRQ
# Attributes:
#
# The attr field of kvm_device_attr encodes the following values:
#
# bits: | 31 .... 5 | 4 .... 0 |
# values: | RES0 | vINTID |
#
# The vINTID specifies which interrupt is generated when the vGIC
# must generate a maintenance interrupt. This must be a PPI.
but this code sets kvmattr.addr to 0 and kvmaddr.addr to
the address of a uint32_t with the vINTID in it.
Looking at the kernel code in vgic_v3_attr_regs_access() it
looks like maybe the kernel docs are wrong, but I'm not sure.
thanks
-- PMM
