Re: [Qemu-devel] [RFC v9 06/17] virtio-iommu: Endpoint and domains structs and helpers

[Bharat Bhushan]

Hi Eric,

> -----Original Message-----
> From: Auger Eric <address@hidden>
> Sent: Friday, November 23, 2018 1:23 PM
> To: Bharat Bhushan <address@hidden>;
> address@hidden; address@hidden; qemu-
> address@hidden; address@hidden; address@hidden; jean-
> address@hidden
> Cc: address@hidden; address@hidden; address@hidden
> Subject: Re: [Qemu-devel] [RFC v9 06/17] virtio-iommu: Endpoint and
> domains structs and helpers
> 
> Hi Bharat,
> 
> On 11/23/18 7:38 AM, Bharat Bhushan wrote:
> > Hi Eric,
> >
> >> -----Original Message-----
> >> From: Eric Auger <address@hidden>
> >> Sent: Thursday, November 22, 2018 10:45 PM
> >> To: address@hidden; address@hidden; qemu-
> >> address@hidden; address@hidden; address@hidden;
> >> address@hidden; address@hidden
> >> Cc: address@hidden; address@hidden; Bharat Bhushan
> >> <address@hidden>; address@hidden
> >> Subject: [RFC v9 06/17] virtio-iommu: Endpoint and domains structs
> >> and helpers
> >>
> >> This patch introduce domain and endpoint internal datatypes. Both are
> >> stored in RB trees. The domain owns a list of endpoints attached to it.
> >>
> >> Helpers to get/put end points and domains are introduced.
> >> get() helpers will become static in subsequent patches.
> >>
> >> Signed-off-by: Eric Auger <address@hidden>
> >>
> >> ---
> >>
> >> v6 -> v7:
> >> - on virtio_iommu_find_add_as the bus number computation may
> >>   not be finalized yet so we cannot register the EPs at that time.
> >>   Hence, let's remove the get_endpoint and also do not use the
> >>   bus number for building the memory region name string (only
> >>   used for debug though).
> >
> > Endpoint registration from virtio_iommu_find_add_as to PROBE request.
> > It is mentioned that " the bus number computation may not be finalized ".
> Can you please give some more information.
> > I am asking this because from vfio perspective translate/replay will be
> called much before the PROBE request and endpoint needed to be
> registered by that time.
> When from virtio_iommu_find_add() gets called, there are cases where the
> BDF of the device is not yet computed, typically if the EP is plugged on a
> secondary bus. That's why I postponed the registration. Do you have idea
> When you would need the registration to happen?

We want the endpoint registeration before replay/translate() is called for both 
virtio/vfio and I am trying to understand when we should register the endpoint.
I am looking at amd iommu, there pci_setup_iommu() provides the callback 
function which is called with "devfn" from pci_device_iommu_address_space(). 
Are you saying that devfn provided by pci_device_iommu_address_space() can be 
invalid? 

Thanks
-Bharat

> 
> Thanks
> 
> Eric
> >
> >
> > Thanks
> > -Bharat
> >
> >>
> >> v4 -> v5:
> >> - initialize as->endpoint_list
> >>
> >> v3 -> v4:
> >> - new separate patch
> >> ---
> >>  hw/virtio/trace-events   |   4 ++
> >>  hw/virtio/virtio-iommu.c | 125
> >> ++++++++++++++++++++++++++++++++++++++-
> >>  2 files changed, 128 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events index
> >> 9270b0463e..4b15086872 100644
> >> --- a/hw/virtio/trace-events
> >> +++ b/hw/virtio/trace-events
> >> @@ -61,3 +61,7 @@ virtio_iommu_map(uint32_t domain_id, uint64_t
> >> virt_start, uint64_t virt_end, uin  virtio_iommu_unmap(uint32_t
> >> domain_id, uint64_t virt_start, uint64_t virt_end) "domain=%d
> virt_start=0x%"PRIx64"
> >> virt_end=0x%"PRIx64  virtio_iommu_translate(const char *name,
> >> uint32_t rid, uint64_t iova, int flag) "mr=%s rid=%d addr=0x%"PRIx64"
> flag=%d"
> >>  virtio_iommu_init_iommu_mr(char *iommu_mr) "init %s"
> >> +virtio_iommu_get_endpoint(uint32_t ep_id) "Alloc endpoint=%d"
> >> +virtio_iommu_put_endpoint(uint32_t ep_id) "Free endpoint=%d"
> >> +virtio_iommu_get_domain(uint32_t domain_id) "Alloc domain=%d"
> >> +virtio_iommu_put_domain(uint32_t domain_id) "Free domain=%d"
> >> diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
> >> index
> >> dead062baf..1b9c3ba416 100644
> >> --- a/hw/virtio/virtio-iommu.c
> >> +++ b/hw/virtio/virtio-iommu.c
> >> @@ -33,20 +33,124 @@
> >>  #include "hw/virtio/virtio-bus.h"
> >>  #include "hw/virtio/virtio-access.h"
> >>  #include "hw/virtio/virtio-iommu.h"
> >> +#include "hw/pci/pci_bus.h"
> >> +#include "hw/pci/pci.h"
> >>
> >>  /* Max size */
> >>  #define VIOMMU_DEFAULT_QUEUE_SIZE 256
> >>
> >> +typedef struct viommu_domain {
> >> +    uint32_t id;
> >> +    GTree *mappings;
> >> +    QLIST_HEAD(, viommu_endpoint) endpoint_list; } viommu_domain;
> >> +
> >> +typedef struct viommu_endpoint {
> >> +    uint32_t id;
> >> +    viommu_domain *domain;
> >> +    QLIST_ENTRY(viommu_endpoint) next;
> >> +    VirtIOIOMMU *viommu;
> >> +} viommu_endpoint;
> >> +
> >> +typedef struct viommu_interval {
> >> +    uint64_t low;
> >> +    uint64_t high;
> >> +} viommu_interval;
> >> +
> >>  static inline uint16_t virtio_iommu_get_sid(IOMMUDevice *dev)  {
> >>      return PCI_BUILD_BDF(pci_bus_num(dev->bus), dev->devfn);  }
> >>
> >> +static gint interval_cmp(gconstpointer a, gconstpointer b, gpointer
> >> +user_data) {
> >> +    viommu_interval *inta = (viommu_interval *)a;
> >> +    viommu_interval *intb = (viommu_interval *)b;
> >> +
> >> +    if (inta->high <= intb->low) {
> >> +        return -1;
> >> +    } else if (intb->high <= inta->low) {
> >> +        return 1;
> >> +    } else {
> >> +        return 0;
> >> +    }
> >> +}
> >> +
> >> +static void
> >> virtio_iommu_detach_endpoint_from_domain(viommu_endpoint
> >> +*ep) {
> >> +    QLIST_REMOVE(ep, next);
> >> +    ep->domain = NULL;
> >> +}
> >> +
> >> +viommu_endpoint *virtio_iommu_get_endpoint(VirtIOIOMMU *s,
> >> uint32_t
> >> +ep_id); viommu_endpoint *virtio_iommu_get_endpoint(VirtIOIOMMU
> *s,
> >> +uint32_t ep_id) {
> >> +    viommu_endpoint *ep;
> >> +
> >> +    ep = g_tree_lookup(s->endpoints, GUINT_TO_POINTER(ep_id));
> >> +    if (ep) {
> >> +        return ep;
> >> +    }
> >> +    ep = g_malloc0(sizeof(*ep));
> >> +    ep->id = ep_id;
> >> +    ep->viommu = s;
> >> +    trace_virtio_iommu_get_endpoint(ep_id);
> >> +    g_tree_insert(s->endpoints, GUINT_TO_POINTER(ep_id), ep);
> >> +    return ep;
> >> +}
> >> +
> >> +static void virtio_iommu_put_endpoint(gpointer data) {
> >> +    viommu_endpoint *ep = (viommu_endpoint *)data;
> >> +
> >> +    if (ep->domain) {
> >> +        virtio_iommu_detach_endpoint_from_domain(ep);
> >> +        g_tree_unref(ep->domain->mappings);
> >> +    }
> >> +
> >> +    trace_virtio_iommu_put_endpoint(ep->id);
> >> +    g_free(ep);
> >> +}
> >> +
> >> +viommu_domain *virtio_iommu_get_domain(VirtIOIOMMU *s,
> uint32_t
> >> +domain_id); viommu_domain
> *virtio_iommu_get_domain(VirtIOIOMMU
> >> *s,
> >> +uint32_t domain_id) {
> >> +    viommu_domain *domain;
> >> +
> >> +    domain = g_tree_lookup(s->domains,
> GUINT_TO_POINTER(domain_id));
> >> +    if (domain) {
> >> +        return domain;
> >> +    }
> >> +    domain = g_malloc0(sizeof(*domain));
> >> +    domain->id = domain_id;
> >> +    domain->mappings =
> >> g_tree_new_full((GCompareDataFunc)interval_cmp,
> >> +                                   NULL, (GDestroyNotify)g_free,
> >> +                                   (GDestroyNotify)g_free);
> >> +    g_tree_insert(s->domains, GUINT_TO_POINTER(domain_id),
> domain);
> >> +    QLIST_INIT(&domain->endpoint_list);
> >> +    trace_virtio_iommu_get_domain(domain_id);
> >> +    return domain;
> >> +}
> >> +
> >> +static void virtio_iommu_put_domain(gpointer data) {
> >> +    viommu_domain *domain = (viommu_domain *)data;
> >> +    viommu_endpoint *iter, *tmp;
> >> +
> >> +    QLIST_FOREACH_SAFE(iter, &domain->endpoint_list, next, tmp) {
> >> +        virtio_iommu_detach_endpoint_from_domain(iter);
> >> +    }
> >> +    g_tree_destroy(domain->mappings);
> >> +    trace_virtio_iommu_put_domain(domain->id);
> >> +    g_free(domain);
> >> +}
> >> +
> >>  static AddressSpace *virtio_iommu_find_add_as(PCIBus *bus, void
> >> *opaque,
> >>                                                int devfn)  {
> >>      VirtIOIOMMU *s = opaque;
> >>      IOMMUPciBus *sbus = g_hash_table_lookup(s->as_by_busptr, bus);
> >> +    static uint32_t mr_index;
> >>      IOMMUDevice *sdev;
> >>
> >>      if (!sbus) {
> >> @@ -60,7 +164,7 @@ static AddressSpace
> >> *virtio_iommu_find_add_as(PCIBus *bus, void *opaque,
> >>      if (!sdev) {
> >>          char *name = g_strdup_printf("%s-%d-%d",
> >>                                       TYPE_VIRTIO_IOMMU_MEMORY_REGION,
> >> -                                     pci_bus_num(bus), devfn);
> >> +                                     mr_index++, devfn);
> >>          sdev = sbus->pbdev[devfn] = g_malloc0(sizeof(IOMMUDevice));
> >>
> >>          sdev->viommu = s;
> >> @@ -75,6 +179,7 @@ static AddressSpace
> >> *virtio_iommu_find_add_as(PCIBus *bus, void *opaque,
> >>                                   UINT64_MAX);
> >>          address_space_init(&sdev->as,
> >>                             MEMORY_REGION(&sdev->iommu_mr),
> >> TYPE_VIRTIO_IOMMU);
> >> +        g_free(name);
> >>      }
> >>
> >>      return &sdev->as;
> >> @@ -332,6 +437,13 @@ static const VMStateDescription
> >> vmstate_virtio_iommu_device = {
> >>      },
> >>  };
> >>
> >> +static gint int_cmp(gconstpointer a, gconstpointer b, gpointer
> >> +user_data) {
> >> +    uint ua = GPOINTER_TO_UINT(a);
> >> +    uint ub = GPOINTER_TO_UINT(b);
> >> +    return (ua > ub) - (ua < ub);
> >> +}
> >> +
> >>  static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
> {
> >>      VirtIODevice *vdev = VIRTIO_DEVICE(dev); @@ -356,6 +468,8 @@
> >> static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
> >>      virtio_add_feature(&s->features, VIRTIO_IOMMU_F_MAP_UNMAP);
> >>      virtio_add_feature(&s->features, VIRTIO_IOMMU_F_BYPASS);
> >>
> >> +    qemu_mutex_init(&s->mutex);
> >> +
> >>      memset(s->as_by_bus_num, 0, sizeof(s->as_by_bus_num));
> >>      s->as_by_busptr = g_hash_table_new(NULL, NULL);
> >>
> >> @@ -364,11 +478,20 @@ static void
> >> virtio_iommu_device_realize(DeviceState *dev, Error **errp)
> >>      } else {
> >>          error_setg(errp, "VIRTIO-IOMMU is not attached to any PCI bus!");
> >>      }
> >> +
> >> +    s->domains = g_tree_new_full((GCompareDataFunc)int_cmp,
> >> +                                 NULL, NULL, virtio_iommu_put_domain);
> >> +    s->endpoints = g_tree_new_full((GCompareDataFunc)int_cmp,
> >> +                                   NULL, NULL,
> >> + virtio_iommu_put_endpoint);
> >>  }
> >>
> >>  static void virtio_iommu_device_unrealize(DeviceState *dev, Error
> >> **errp) {
> >>      VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> >> +    VirtIOIOMMU *s = VIRTIO_IOMMU(dev);
> >> +
> >> +    g_tree_destroy(s->domains);
> >> +    g_tree_destroy(s->endpoints);
> >>
> >>      virtio_cleanup(vdev);
> >>  }
> >> --
> >> 2.17.2
> >
> >