On Aug 11 23:37, Jinhao Fan wrote:
> When irqfd is enabled, we bypass QEMU's irq emulation and let KVM to
> directly assert the irq. However, KVM is not aware of the device's MSI-x
> masking status. Add MSI-x mask bookkeeping in NVMe emulation and
> detach the corresponding irqfd when the certain vector is masked.
>
> Signed-off-by: Jinhao Fan <fanjinhao...@ict.ac.cn>
> ---
> hw/nvme/ctrl.c | 82 ++++++++++++++++++++++++++++++++++++++++++++
> hw/nvme/nvme.h | 2 ++
> hw/nvme/trace-events | 3 ++
> 3 files changed, 87 insertions(+)
>
> diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c
> index 63f988f2f9..ac5460c7c8 100644
> --- a/hw/nvme/ctrl.c
> +++ b/hw/nvme/ctrl.c
> @@ -7478,10 +7478,84 @@ static int nvme_add_pm_capability(PCIDevice *pci_dev,
> uint8_t offset)
>
> return 0;
> }
> +static int nvme_vector_unmask(PCIDevice *pci_dev, unsigned vector,
> + MSIMessage msg)
> +{
> + NvmeCtrl *n = NVME(pci_dev);
> + int ret;
> +
> + trace_pci_nvme_irq_unmask(vector, msg.address, msg.data);
> +
> + for (uint32_t i = 0; i < n->params.max_ioqpairs + 1; i++) {
This loop is OK for now, but could be done better with a reverse
mapping.
This is just an observation. Don't spend time on doing it since we are
not aware of any host actually doing masking/unmasking.
> + NvmeCQueue *cq = n->cq[i];
> + /*
> + * If this function is called, then irqfd must be available.
> Therefore,
> + * irqfd must be in use if cq->assert_notifier.initialized is true.
> + */
The wording indicates that you want to assert() that assumption instead.
> + if (cq && cq->vector == vector && cq->assert_notifier.initialized) {
> + if (cq->msg.data != msg.data || cq->msg.address != msg.address) {
> + ret = kvm_irqchip_update_msi_route(kvm_state, cq->virq, msg,
> + pci_dev);
> + if (ret < 0) {
> + return ret;
> + }
> + kvm_irqchip_commit_routes(kvm_state);
> + cq->msg = msg;
> + }
> +
> + ret = kvm_irqchip_add_irqfd_notifier_gsi(kvm_state,
> + &cq->assert_notifier,
> + NULL, cq->virq);
> + if (ret < 0) {
> + return ret;
> + }
> + }
> + }
> +
> + return 0;
> +}
> +
> +static void nvme_vector_mask(PCIDevice *pci_dev, unsigned vector)
> +{
> + NvmeCtrl *n = NVME(pci_dev);
> +
> + trace_pci_nvme_irq_mask(vector);
> +
> + for (uint32_t i = 0; i < n->params.max_ioqpairs + 1; i++) {
> + NvmeCQueue *cq = n->cq[i];
> + if (cq && cq->vector == vector && cq->assert_notifier.initialized) {
> + kvm_irqchip_remove_irqfd_notifier_gsi(kvm_state,
> + &cq->assert_notifier,
> + cq->virq);
> + }
> + }
> +}
> +
> +static void nvme_vector_poll(PCIDevice *pci_dev,
> + unsigned int vector_start,
> + unsigned int vector_end)
> +{
> + NvmeCtrl *n = NVME(pci_dev);
> +
> + trace_pci_nvme_irq_poll(vector_start, vector_end);
> +
> + for (uint32_t i = 0; i < n->params.max_ioqpairs + 1; i++) {
> + NvmeCQueue *cq = n->cq[i];
> + if (cq && cq->vector >= vector_start && cq->vector <= vector_end
> + && msix_is_masked(pci_dev, cq->vector)
> + && cq->assert_notifier.initialized) {
> + if (event_notifier_test_and_clear(&cq->assert_notifier)) {
> + msix_set_pending(pci_dev, i);
> + }
> + }
> + }
> +}
I'm a little fuzzy on this - what causes this function to be invoked?
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