From 660c97eef6f8f416c5dc24d3798e29f9f9f698fb Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Thu, 9 Jul 2015 15:50:13 +0200 Subject: ivshmem: use kvm irqfd for msi notifications MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Use irqfd for improving context switch when notifying the guest. If the host doesn't support kvm irqfd, regular msi notifications are still supported. Note: the ivshmem implementation doesn't allow switching between MSI and IO interrupts, this patch doesn't either. Signed-off-by: Marc-André Lureau Reviewed-by: Paolo Bonzini --- hw/misc/ivshmem.c | 180 ++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 174 insertions(+), 6 deletions(-) diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c index c6be33c2ef..e9dae834da 100644 --- a/hw/misc/ivshmem.c +++ b/hw/misc/ivshmem.c @@ -19,6 +19,7 @@ #include "hw/hw.h" #include "hw/i386/pc.h" #include "hw/pci/pci.h" +#include "hw/pci/msi.h" #include "hw/pci/msix.h" #include "sysemu/kvm.h" #include "migration/migration.h" @@ -68,6 +69,7 @@ typedef struct Peer { typedef struct MSIVector { PCIDevice *pdev; + int virq; } MSIVector; typedef struct IVShmemState { @@ -293,13 +295,73 @@ static void fake_irqfd(void *opaque, const uint8_t *buf, int size) { msix_notify(pdev, vector); } +static int ivshmem_vector_unmask(PCIDevice *dev, unsigned vector, + MSIMessage msg) +{ + IVShmemState *s = IVSHMEM(dev); + EventNotifier *n = &s->peers[s->vm_id].eventfds[vector]; + MSIVector *v = &s->msi_vectors[vector]; + int ret; + + IVSHMEM_DPRINTF("vector unmask %p %d\n", dev, vector); + + ret = kvm_irqchip_update_msi_route(kvm_state, v->virq, msg, dev); + if (ret < 0) { + return ret; + } + + return kvm_irqchip_add_irqfd_notifier_gsi(kvm_state, n, NULL, v->virq); +} + +static void ivshmem_vector_mask(PCIDevice *dev, unsigned vector) +{ + IVShmemState *s = IVSHMEM(dev); + EventNotifier *n = &s->peers[s->vm_id].eventfds[vector]; + int ret; + + IVSHMEM_DPRINTF("vector mask %p %d\n", dev, vector); + + ret = kvm_irqchip_remove_irqfd_notifier_gsi(kvm_state, n, + s->msi_vectors[vector].virq); + if (ret != 0) { + error_report("remove_irqfd_notifier_gsi failed"); + } +} + +static void ivshmem_vector_poll(PCIDevice *dev, + unsigned int vector_start, + unsigned int vector_end) +{ + IVShmemState *s = IVSHMEM(dev); + unsigned int vector; + + IVSHMEM_DPRINTF("vector poll %p %d-%d\n", dev, vector_start, vector_end); + + vector_end = MIN(vector_end, s->vectors); + + for (vector = vector_start; vector < vector_end; vector++) { + EventNotifier *notifier = &s->peers[s->vm_id].eventfds[vector]; + + if (!msix_is_masked(dev, vector)) { + continue; + } + + if (event_notifier_test_and_clear(notifier)) { + msix_set_pending(dev, vector); + } + } +} + static CharDriverState* create_eventfd_chr_device(void * opaque, EventNotifier *n, int vector) { /* create a event character device based on the passed eventfd */ IVShmemState *s = opaque; - CharDriverState * chr; + PCIDevice *pdev = PCI_DEVICE(s); int eventfd = event_notifier_get_fd(n); + CharDriverState *chr; + + s->msi_vectors[vector].pdev = pdev; chr = qemu_chr_open_eventfd(eventfd); @@ -484,6 +546,58 @@ static bool fifo_update_and_get(IVShmemState *s, const uint8_t *buf, int size, return true; } +static int ivshmem_add_kvm_msi_virq(IVShmemState *s, int vector) +{ + PCIDevice *pdev = PCI_DEVICE(s); + MSIMessage msg = msix_get_message(pdev, vector); + int ret; + + IVSHMEM_DPRINTF("ivshmem_add_kvm_msi_virq vector:%d\n", vector); + + if (s->msi_vectors[vector].pdev != NULL) { + return 0; + } + + ret = kvm_irqchip_add_msi_route(kvm_state, msg, pdev); + if (ret < 0) { + error_report("ivshmem: kvm_irqchip_add_msi_route failed"); + return -1; + } + + s->msi_vectors[vector].virq = ret; + s->msi_vectors[vector].pdev = pdev; + + return 0; +} + +static void setup_interrupt(IVShmemState *s, int vector) +{ + EventNotifier *n = &s->peers[s->vm_id].eventfds[vector]; + bool with_irqfd = kvm_msi_via_irqfd_enabled() && + ivshmem_has_feature(s, IVSHMEM_MSI); + PCIDevice *pdev = PCI_DEVICE(s); + + IVSHMEM_DPRINTF("setting up interrupt for vector: %d\n", vector); + + if (!with_irqfd) { + IVSHMEM_DPRINTF("with eventfd"); + s->eventfd_chr[vector] = create_eventfd_chr_device(s, n, vector); + } else if (msix_enabled(pdev)) { + IVSHMEM_DPRINTF("with irqfd"); + if (ivshmem_add_kvm_msi_virq(s, vector) < 0) { + return; + } + + if (!msix_is_masked(pdev, vector)) { + kvm_irqchip_add_irqfd_notifier_gsi(kvm_state, n, NULL, + s->msi_vectors[vector].virq); + } + } else { + /* it will be delayed until msix is enabled, in write_config */ + IVSHMEM_DPRINTF("with irqfd, delayed until msix enabled"); + } +} + static void ivshmem_read(void *opaque, const uint8_t *buf, int size) { IVShmemState *s = opaque; @@ -586,11 +700,10 @@ static void ivshmem_read(void *opaque, const uint8_t *buf, int size) IVSHMEM_DPRINTF("eventfds[%ld][%d] = %d\n", incoming_posn, new_eventfd, incoming_fd); event_notifier_init_fd(&peer->eventfds[new_eventfd], incoming_fd); + fcntl_setfl(incoming_fd, O_NONBLOCK); /* msix/irqfd poll non block */ if (incoming_posn == s->vm_id) { - s->eventfd_chr[new_eventfd] = create_eventfd_chr_device(s, - &s->peers[s->vm_id].eventfds[new_eventfd], - new_eventfd); + setup_interrupt(s, new_eventfd); } if (ivshmem_has_feature(s, IVSHMEM_IOEVENTFD)) { @@ -665,10 +778,65 @@ static int ivshmem_setup_msi(IVShmemState * s) return 0; } -static void ivshmem_write_config(PCIDevice *pci_dev, uint32_t address, +static void ivshmem_enable_irqfd(IVShmemState *s) +{ + PCIDevice *pdev = PCI_DEVICE(s); + int i; + + for (i = 0; i < s->peers[s->vm_id].nb_eventfds; i++) { + ivshmem_add_kvm_msi_virq(s, i); + } + + if (msix_set_vector_notifiers(pdev, + ivshmem_vector_unmask, + ivshmem_vector_mask, + ivshmem_vector_poll)) { + error_report("ivshmem: msix_set_vector_notifiers failed"); + } +} + +static void ivshmem_remove_kvm_msi_virq(IVShmemState *s, int vector) +{ + IVSHMEM_DPRINTF("ivshmem_remove_kvm_msi_virq vector:%d\n", vector); + + if (s->msi_vectors[vector].pdev == NULL) { + return; + } + + /* it was cleaned when masked in the frontend. */ + kvm_irqchip_release_virq(kvm_state, s->msi_vectors[vector].virq); + + s->msi_vectors[vector].pdev = NULL; +} + +static void ivshmem_disable_irqfd(IVShmemState *s) +{ + PCIDevice *pdev = PCI_DEVICE(s); + int i; + + for (i = 0; i < s->peers[s->vm_id].nb_eventfds; i++) { + ivshmem_remove_kvm_msi_virq(s, i); + } + + msix_unset_vector_notifiers(pdev); +} + +static void ivshmem_write_config(PCIDevice *pdev, uint32_t address, uint32_t val, int len) { - pci_default_write_config(pci_dev, address, val, len); + IVShmemState *s = IVSHMEM(pdev); + int is_enabled, was_enabled = msix_enabled(pdev); + + pci_default_write_config(pdev, address, val, len); + is_enabled = msix_enabled(pdev); + + if (kvm_msi_via_irqfd_enabled() && s->vm_id != -1) { + if (!was_enabled && is_enabled) { + ivshmem_enable_irqfd(s); + } else if (was_enabled && !is_enabled) { + ivshmem_disable_irqfd(s); + } + } } static void pci_ivshmem_realize(PCIDevice *dev, Error **errp) -- cgit v1.2.3