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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v12 25/34] ARM: vITS: handle MAPD command
On Wed, 14 Jun 2017, Andre Przywara wrote:
> The MAPD command maps a device by associating a memory region for
> storing ITEs with a certain device ID. Since it features a valid bit,
> MAPD also covers the "unmap" functionality, which we also cover here.
> We store the given guest physical address in the device table, and, if
> this command comes from Dom0, tell the host ITS driver about this new
> mapping, so it can issue the corresponding host MAPD command and create
> the required tables. We take care of rolling back actions should one
> step fail.
> Upon unmapping a device we make sure we clean up all associated
> resources and release the memory again.
> We use our existing guest memory access function to find the right ITT
> entry and store the mapping there (in guest memory).
>
> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> ---
> xen/arch/arm/gic-v3-its.c | 17 +++++
> xen/arch/arm/gic-v3-lpi.c | 17 +++++
> xen/arch/arm/vgic-v3-its.c | 142
> +++++++++++++++++++++++++++++++++++++++
> xen/include/asm-arm/gic_v3_its.h | 5 ++
> 4 files changed, 181 insertions(+)
>
> diff --git a/xen/arch/arm/gic-v3-its.c b/xen/arch/arm/gic-v3-its.c
> index 38f0840..8864e0b 100644
> --- a/xen/arch/arm/gic-v3-its.c
> +++ b/xen/arch/arm/gic-v3-its.c
> @@ -859,6 +859,23 @@ struct pending_irq
> *gicv3_its_get_event_pending_irq(struct domain *d,
> return get_event_pending_irq(d, vdoorbell_address, vdevid, eventid,
> NULL);
> }
>
> +int gicv3_remove_guest_event(struct domain *d, paddr_t vdoorbell_address,
> + uint32_t vdevid, uint32_t eventid)
> +{
> + uint32_t host_lpi = INVALID_LPI;
> +
> + if ( !get_event_pending_irq(d, vdoorbell_address, vdevid, eventid,
> + &host_lpi) )
> + return -EINVAL;
> +
> + if ( host_lpi == INVALID_LPI )
> + return -EINVAL;
> +
> + gicv3_lpi_update_host_entry(host_lpi, d->domain_id, INVALID_LPI);
> +
> + return 0;
> +}
> +
> /* Scan the DT for any ITS nodes and create a list of host ITSes out of it.
> */
> void gicv3_its_dt_init(const struct dt_device_node *node)
> {
> diff --git a/xen/arch/arm/gic-v3-lpi.c b/xen/arch/arm/gic-v3-lpi.c
> index dc936fa..c3474f5 100644
> --- a/xen/arch/arm/gic-v3-lpi.c
> +++ b/xen/arch/arm/gic-v3-lpi.c
> @@ -215,6 +215,23 @@ out:
> irq_exit();
> }
>
> +void gicv3_lpi_update_host_entry(uint32_t host_lpi, int domain_id,
> + uint32_t virt_lpi)
> +{
> + union host_lpi *hlpip, hlpi;
> +
> + ASSERT(host_lpi >= LPI_OFFSET);
> +
> + host_lpi -= LPI_OFFSET;
> +
> + hlpip = &lpi_data.host_lpis[host_lpi / HOST_LPIS_PER_PAGE][host_lpi %
> HOST_LPIS_PER_PAGE];
> +
> + hlpi.virt_lpi = virt_lpi;
> + hlpi.dom_id = domain_id;
> +
> + write_u64_atomic(&hlpip->data, hlpi.data);
> +}
> +
> static int gicv3_lpi_allocate_pendtable(uint64_t *reg)
> {
> uint64_t val;
> diff --git a/xen/arch/arm/vgic-v3-its.c b/xen/arch/arm/vgic-v3-its.c
> index 4552bc9..d236bbe 100644
> --- a/xen/arch/arm/vgic-v3-its.c
> +++ b/xen/arch/arm/vgic-v3-its.c
> @@ -159,6 +159,21 @@ static struct vcpu *get_vcpu_from_collection(struct
> virt_its *its,
> return its->d->vcpu[vcpu_id];
> }
>
> +/* Set the address of an ITT for a given device ID. */
> +static int its_set_itt_address(struct virt_its *its, uint32_t devid,
> + paddr_t itt_address, uint32_t nr_bits)
> +{
> + paddr_t addr = get_baser_phys_addr(its->baser_dev);
> + dev_table_entry_t itt_entry = DEV_TABLE_ENTRY(itt_address, nr_bits);
> +
> + if ( devid >= its->max_devices )
> + return -ENOENT;
> +
> + return vgic_access_guest_memory(its->d,
> + addr + devid * sizeof(dev_table_entry_t),
> + &itt_entry, sizeof(itt_entry), true);
> +}
> +
> /*
> * Lookup the address of the Interrupt Translation Table associated with
> * that device ID.
> @@ -375,6 +390,130 @@ out_unlock:
> return ret;
> }
>
> +/* Must be called with the ITS lock held. */
> +static int its_discard_event(struct virt_its *its,
> + uint32_t vdevid, uint32_t vevid)
> +{
> + struct pending_irq *p;
> + unsigned long flags;
> + struct vcpu *vcpu;
> + uint32_t vlpi;
> +
> + ASSERT(spin_is_locked(&its->its_lock));
> +
> + if ( !read_itte(its, vdevid, vevid, &vcpu, &vlpi) )
> + return -ENOENT;
> +
> + if ( vlpi == INVALID_LPI )
> + return -ENOENT;
> +
> + /*
> + * TODO: This relies on the VCPU being correct in the ITS tables.
> + * This can be fixed by either using a per-IRQ lock or by using
> + * the VCPU ID from the pending_irq instead.
> + */
> + spin_lock_irqsave(&vcpu->arch.vgic.lock, flags);
> +
> + /* Remove the pending_irq from the tree. */
> + write_lock(&its->d->arch.vgic.pend_lpi_tree_lock);
> + p = radix_tree_delete(&its->d->arch.vgic.pend_lpi_tree, vlpi);
> + write_unlock(&its->d->arch.vgic.pend_lpi_tree_lock);
> +
> + if ( !p )
> + {
> + spin_unlock_irqrestore(&vcpu->arch.vgic.lock, flags);
> +
> + return -ENOENT;
> + }
> +
> + /* Cleanup the pending_irq and disconnect it from the LPI. */
> + gic_remove_irq_from_queues(vcpu, p);
> + vgic_init_pending_irq(p, INVALID_LPI);
> +
> + spin_unlock_irqrestore(&vcpu->arch.vgic.lock, flags);
> +
> + /* Remove the corresponding host LPI entry */
> + return gicv3_remove_guest_event(its->d, its->doorbell_address,
> + vdevid, vevid);
> +}
> +
> +static void its_unmap_device(struct virt_its *its, uint32_t devid)
> +{
> + dev_table_entry_t itt;
> + uint64_t evid;
> +
> + spin_lock(&its->its_lock);
> +
> + if ( its_get_itt(its, devid, &itt) )
> + goto out;
> +
> + /*
> + * For DomUs we need to check that the number of events per device
> + * is really limited, otherwise looping over all events can take too
> + * long for a guest. This ASSERT can then be removed if that is
> + * covered.
> + */
> + ASSERT(is_hardware_domain(its->d));
> +
> + for ( evid = 0; evid < DEV_TABLE_ITT_SIZE(itt); evid++ )
> + /* Don't care about errors here, clean up as much as possible. */
> + its_discard_event(its, devid, evid);
> +
> +out:
> + spin_unlock(&its->its_lock);
> +}
> +
> +static int its_handle_mapd(struct virt_its *its, uint64_t *cmdptr)
> +{
> + /* size and devid get validated by the functions called below. */
> + uint32_t devid = its_cmd_get_deviceid(cmdptr);
> + unsigned int size = its_cmd_get_size(cmdptr) + 1;
> + bool valid = its_cmd_get_validbit(cmdptr);
> + paddr_t itt_addr = its_cmd_get_ittaddr(cmdptr);
> + int ret;
> +
> + /* Sanitize the number of events. */
> + if ( valid && (size > its->evid_bits) )
> + return -1;
> +
> + if ( !valid )
> + /* Discard all events and remove pending LPIs. */
> + its_unmap_device(its, devid);
> +
> + /*
> + * There is no easy and clean way for Xen to know the ITS device ID of a
> + * particular (PCI) device, so we have to rely on the guest telling
> + * us about it. For *now* we are just using the device ID *Dom0* uses,
> + * because the driver there has the actual knowledge.
> + * Eventually this will be replaced with a dedicated hypercall to
> + * announce pass-through of devices.
> + */
> + if ( is_hardware_domain(its->d) )
> + {
> +
> + /*
> + * Dom0's ITSes are mapped 1:1, so both addresses are the same.
> + * Also the device IDs are equal.
> + */
> + ret = gicv3_its_map_guest_device(its->d, its->doorbell_address,
> devid,
> + its->doorbell_address, devid,
> + BIT(size), valid);
> + if ( ret && valid )
> + return ret;
> + }
> +
> + spin_lock(&its->its_lock);
> +
> + if ( valid )
> + ret = its_set_itt_address(its, devid, itt_addr, size);
> + else
> + ret = its_set_itt_address(its, devid, INVALID_PADDR, 1);
> +
> + spin_unlock(&its->its_lock);
> +
> + return ret;
> +}
> +
> #define ITS_CMD_BUFFER_SIZE(baser) ((((baser) & 0xff) + 1) << 12)
> #define ITS_CMD_OFFSET(reg) ((reg) & GENMASK(19, 5))
>
> @@ -420,6 +559,9 @@ static int vgic_its_handle_cmds(struct domain *d, struct
> virt_its *its)
> case GITS_CMD_MAPC:
> ret = its_handle_mapc(its, command);
> break;
> + case GITS_CMD_MAPD:
> + ret = its_handle_mapd(its, command);
> + break;
> case GITS_CMD_SYNC:
> /* We handle ITS commands synchronously, so we ignore SYNC. */
> break;
> diff --git a/xen/include/asm-arm/gic_v3_its.h
> b/xen/include/asm-arm/gic_v3_its.h
> index be67726..0089ac2 100644
> --- a/xen/include/asm-arm/gic_v3_its.h
> +++ b/xen/include/asm-arm/gic_v3_its.h
> @@ -175,6 +175,11 @@ struct pending_irq
> *gicv3_its_get_event_pending_irq(struct domain *d,
> paddr_t
> vdoorbell_address,
> uint32_t vdevid,
> uint32_t eventid);
> +int gicv3_remove_guest_event(struct domain *d, paddr_t vdoorbell_address,
> + uint32_t vdevid, uint32_t eventid);
> +void gicv3_lpi_update_host_entry(uint32_t host_lpi, int domain_id,
> + uint32_t virt_lpi);
> +
> #else
>
> static inline void gicv3_its_dt_init(const struct dt_device_node *node)
> --
> 2.9.0
>
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