Currently the virtio-iommu device must be programmed before it allows DMA from any PCI device. This can make the VM entirely unusable when a virtio-iommu driver isn't present, for example in a bootloader that loads the OS from storage.
Similarly to the other vIOMMU implementations, default to DMA bypassing the IOMMU during boot. Add a "boot-bypass" property, defaulting to true, that lets users change this behavior. Replace the VIRTIO_IOMMU_F_BYPASS feature, which didn't support bypass before feature negotiation, with VIRTIO_IOMMU_F_BYPASS_CONFIG. Signed-off-by: Jean-Philippe Brucker <jean-phili...@linaro.org> --- include/hw/virtio/virtio-iommu.h | 1 + hw/virtio/virtio-iommu.c | 51 +++++++++++++++++++++++++++++--- hw/virtio/trace-events | 4 ++- 3 files changed, 51 insertions(+), 5 deletions(-) diff --git a/include/hw/virtio/virtio-iommu.h b/include/hw/virtio/virtio-iommu.h index e2339e5b72..84391f8448 100644 --- a/include/hw/virtio/virtio-iommu.h +++ b/include/hw/virtio/virtio-iommu.h @@ -58,6 +58,7 @@ struct VirtIOIOMMU { GTree *domains; QemuMutex mutex; GTree *endpoints; + bool boot_bypass; }; #endif diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c index aa9c16a17b..ec02029bb6 100644 --- a/hw/virtio/virtio-iommu.c +++ b/hw/virtio/virtio-iommu.c @@ -24,6 +24,7 @@ #include "hw/qdev-properties.h" #include "hw/virtio/virtio.h" #include "sysemu/kvm.h" +#include "sysemu/reset.h" #include "qapi/error.h" #include "qemu/error-report.h" #include "trace.h" @@ -728,8 +729,7 @@ static IOMMUTLBEntry virtio_iommu_translate(IOMMUMemoryRegion *mr, hwaddr addr, .perm = IOMMU_NONE, }; - bypass_allowed = virtio_vdev_has_feature(&s->parent_obj, - VIRTIO_IOMMU_F_BYPASS); + bypass_allowed = s->config.bypass; sid = virtio_iommu_get_bdf(sdev); @@ -831,13 +831,37 @@ static void virtio_iommu_get_config(VirtIODevice *vdev, uint8_t *config_data) out_config->domain_range.start = cpu_to_le32(dev_config->domain_range.start); out_config->domain_range.end = cpu_to_le32(dev_config->domain_range.end); out_config->probe_size = cpu_to_le32(dev_config->probe_size); + out_config->bypass = dev_config->bypass; trace_virtio_iommu_get_config(dev_config->page_size_mask, dev_config->input_range.start, dev_config->input_range.end, dev_config->domain_range.start, dev_config->domain_range.end, - dev_config->probe_size); + dev_config->probe_size, + dev_config->bypass); +} + +static void virtio_iommu_set_config(VirtIODevice *vdev, + const uint8_t *config_data) +{ + VirtIOIOMMU *dev = VIRTIO_IOMMU(vdev); + struct virtio_iommu_config *dev_config = &dev->config; + const struct virtio_iommu_config *in_config = (void *)config_data; + + if (in_config->bypass != dev_config->bypass) { + if (!virtio_vdev_has_feature(vdev, VIRTIO_IOMMU_F_BYPASS_CONFIG)) { + virtio_error(vdev, "cannot set config.bypass"); + return; + } else if (in_config->bypass != 0 && in_config->bypass != 1) { + virtio_error(vdev, "invalid config.bypass value '%u'", + in_config->bypass); + return; + } + dev_config->bypass = in_config->bypass; + } + + trace_virtio_iommu_set_config(in_config->bypass); } static uint64_t virtio_iommu_get_features(VirtIODevice *vdev, uint64_t f, @@ -963,6 +987,19 @@ static int virtio_iommu_set_page_size_mask(IOMMUMemoryRegion *mr, return 0; } +static void virtio_iommu_system_reset(void *opaque) +{ + VirtIOIOMMU *s = opaque; + + trace_virtio_iommu_system_reset(); + + /* + * config.bypass is sticky across device reset, but should be restored on + * system reset + */ + s->config.bypass = s->boot_bypass; +} + static void virtio_iommu_device_realize(DeviceState *dev, Error **errp) { VirtIODevice *vdev = VIRTIO_DEVICE(dev); @@ -988,9 +1025,9 @@ static void virtio_iommu_device_realize(DeviceState *dev, Error **errp) virtio_add_feature(&s->features, VIRTIO_IOMMU_F_INPUT_RANGE); virtio_add_feature(&s->features, VIRTIO_IOMMU_F_DOMAIN_RANGE); virtio_add_feature(&s->features, VIRTIO_IOMMU_F_MAP_UNMAP); - virtio_add_feature(&s->features, VIRTIO_IOMMU_F_BYPASS); virtio_add_feature(&s->features, VIRTIO_IOMMU_F_MMIO); virtio_add_feature(&s->features, VIRTIO_IOMMU_F_PROBE); + virtio_add_feature(&s->features, VIRTIO_IOMMU_F_BYPASS_CONFIG); qemu_mutex_init(&s->mutex); @@ -1001,6 +1038,8 @@ static void virtio_iommu_device_realize(DeviceState *dev, Error **errp) } else { error_setg(errp, "VIRTIO-IOMMU is not attached to any PCI bus!"); } + + qemu_register_reset(virtio_iommu_system_reset, s); } static void virtio_iommu_device_unrealize(DeviceState *dev) @@ -1008,6 +1047,8 @@ static void virtio_iommu_device_unrealize(DeviceState *dev) VirtIODevice *vdev = VIRTIO_DEVICE(dev); VirtIOIOMMU *s = VIRTIO_IOMMU(dev); + qemu_unregister_reset(virtio_iommu_system_reset, s); + g_hash_table_destroy(s->as_by_busptr); if (s->domains) { g_tree_destroy(s->domains); @@ -1164,6 +1205,7 @@ static const VMStateDescription vmstate_virtio_iommu = { static Property virtio_iommu_properties[] = { DEFINE_PROP_LINK("primary-bus", VirtIOIOMMU, primary_bus, "PCI", PCIBus *), + DEFINE_PROP_BOOL("boot-bypass", VirtIOIOMMU, boot_bypass, true), DEFINE_PROP_END_OF_LIST(), }; @@ -1180,6 +1222,7 @@ static void virtio_iommu_class_init(ObjectClass *klass, void *data) vdc->unrealize = virtio_iommu_device_unrealize; vdc->reset = virtio_iommu_device_reset; vdc->get_config = virtio_iommu_get_config; + vdc->set_config = virtio_iommu_set_config; vdc->get_features = virtio_iommu_get_features; vdc->set_status = virtio_iommu_set_status; vdc->vmsd = &vmstate_virtio_iommu_device; diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events index f7ad6be5fb..a5102eac9e 100644 --- a/hw/virtio/trace-events +++ b/hw/virtio/trace-events @@ -89,9 +89,11 @@ virtio_mmio_setting_irq(int level) "virtio_mmio setting IRQ %d" # virtio-iommu.c virtio_iommu_device_reset(void) "reset!" +virtio_iommu_system_reset(void) "system reset!" virtio_iommu_get_features(uint64_t features) "device supports features=0x%"PRIx64 virtio_iommu_device_status(uint8_t status) "driver status = %d" -virtio_iommu_get_config(uint64_t page_size_mask, uint64_t start, uint64_t end, uint32_t domain_start, uint32_t domain_end, uint32_t probe_size) "page_size_mask=0x%"PRIx64" input range start=0x%"PRIx64" input range end=0x%"PRIx64" domain range start=%d domain range end=%d probe_size=0x%x" +virtio_iommu_get_config(uint64_t page_size_mask, uint64_t start, uint64_t end, uint32_t domain_start, uint32_t domain_end, uint32_t probe_size, uint8_t bypass) "page_size_mask=0x%"PRIx64" input range start=0x%"PRIx64" input range end=0x%"PRIx64" domain range start=%d domain range end=%d probe_size=0x%x bypass=0x%x" +virtio_iommu_set_config(uint8_t bypass) "bypass=0x%x" virtio_iommu_attach(uint32_t domain_id, uint32_t ep_id) "domain=%d endpoint=%d" virtio_iommu_detach(uint32_t domain_id, uint32_t ep_id) "domain=%d endpoint=%d" virtio_iommu_map(uint32_t domain_id, uint64_t virt_start, uint64_t virt_end, uint64_t phys_start, uint32_t flags) "domain=%d virt_start=0x%"PRIx64" virt_end=0x%"PRIx64 " phys_start=0x%"PRIx64" flags=%d" -- 2.34.1