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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v5 23/30] ARM: vITS: handle MAPTI command
Hi,
On 06/04/17 01:45, Stefano Stabellini wrote:
> On Thu, 6 Apr 2017, Andre Przywara wrote:
>> The MAPTI commands associates a DeviceID/EventID pair with a LPI/CPU
>> pair and actually instantiates LPI interrupts.
>> We connect the already allocated host LPI to this virtual LPI, so that
>> any triggering LPI on the host can be quickly forwarded to a guest.
>> Beside entering the VCPU and the virtual LPI number in the respective
>> host LPI entry, we also initialize and add the already allocated
>> struct pending_irq to our radix tree, so that we can now easily find it
>> by its virtual LPI number.
>> To be able to later find the targetting VCPU for any given LPI without
>> having to walk *all* ITS tables, we store the VCPU ID in the pending_irq
>> struct as well.
>> This exports the vgic_init_pending_irq() function to be able to
>> initialize a new struct pending_irq.
>> As write_itte() is now eventually used, we can now add the static tag.
>>
>> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
>> ---
>> xen/arch/arm/gic-v3-its.c | 74 ++++++++++++++++++++++++++++++++++++++
>> xen/arch/arm/gic-v3-lpi.c | 18 ++++++++++
>> xen/arch/arm/vgic-v3-its.c | 76
>> ++++++++++++++++++++++++++++++++++++++--
>> xen/arch/arm/vgic.c | 2 +-
>> xen/include/asm-arm/gic_v3_its.h | 6 ++++
>> xen/include/asm-arm/vgic.h | 2 ++
>> 6 files changed, 175 insertions(+), 3 deletions(-)
>>
>> diff --git a/xen/arch/arm/gic-v3-its.c b/xen/arch/arm/gic-v3-its.c
>> index 76b0316..d970119 100644
>> --- a/xen/arch/arm/gic-v3-its.c
>> +++ b/xen/arch/arm/gic-v3-its.c
>> @@ -777,6 +777,80 @@ out:
>> return ret;
>> }
>>
>> +/* Must be called with the its_device_lock held. */
>> +static struct its_devices *get_its_device(struct domain *d, paddr_t
>> vdoorbell,
>> + uint32_t vdevid)
>> +{
>> + struct rb_node *node = d->arch.vgic.its_devices.rb_node;
>> + struct its_devices *dev;
>> +
>> + ASSERT(spin_is_locked(&d->arch.vgic.its_devices_lock));
>> +
>> + while (node)
>> + {
>> + int cmp;
>> +
>> + dev = rb_entry(node, struct its_devices, rbnode);
>> + cmp = compare_its_guest_devices(dev, vdoorbell, vdevid);
>> +
>> + if ( !cmp )
>> + return dev;
>> +
>> + if ( cmp > 0 )
>> + node = node->rb_left;
>> + else
>> + node = node->rb_right;
>> + }
>> +
>> + return NULL;
>> +}
>> +
>> +static uint32_t get_host_lpi(struct its_devices *dev, uint32_t eventid)
>> +{
>> + uint32_t host_lpi = 0;
>> +
>> + if ( dev && (eventid < dev->eventids) )
>> + host_lpi = dev->host_lpi_blocks[eventid / LPI_BLOCK] +
>> + (eventid % LPI_BLOCK);
>> +
>> + return host_lpi;
>> +}
>> +
>> +/*
>> + * Connects the event ID for an already assigned device to the given
>> VCPU/vLPI
>> + * pair. The corresponding physical LPI is already mapped on the host side
>> + * (when assigning the physical device to the guest), so we just connect the
>> + * target VCPU/vLPI pair to that interrupt to inject it properly if it
>> fires.
>> + * Returns a pointer to the already allocated struct pending_irq that is
>> + * meant to be used by that event.
>> + */
>> +struct pending_irq *gicv3_assign_guest_event(struct domain *d,
>> + paddr_t vdoorbell_address,
>> + uint32_t vdevid, uint32_t
>> veventid,
>> + struct vcpu *v, uint32_t
>> virt_lpi)
>> +{
>> + struct its_devices *dev;
>> + struct pending_irq *pirq = NULL;
>> + uint32_t host_lpi = 0;
>> +
>> + spin_lock(&d->arch.vgic.its_devices_lock);
>> + dev = get_its_device(d, vdoorbell_address, vdevid);
>> + if ( dev )
>> + {
>> + host_lpi = get_host_lpi(dev, veventid);
>> + pirq = &dev->pend_irqs[veventid];
>> + }
>> + spin_unlock(&d->arch.vgic.its_devices_lock);
>> +
>> + if ( !host_lpi || !pirq )
>> + return NULL;
>> +
>> + gicv3_lpi_update_host_entry(host_lpi, d->domain_id,
>> + v ? v->vcpu_id : INVALID_VCPU_ID, virt_lpi);
>> +
>> + return pirq;
>> +}
>> +
>> /* 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 7d20986..c997ed5 100644
>> --- a/xen/arch/arm/gic-v3-lpi.c
>> +++ b/xen/arch/arm/gic-v3-lpi.c
>> @@ -216,6 +216,24 @@ void gicv3_do_LPI(unsigned int lpi)
>> rcu_unlock_domain(d);
>> }
>>
>> +void gicv3_lpi_update_host_entry(uint32_t host_lpi, int domain_id,
>> + unsigned int vcpu_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;
>> + hlpi.vcpu_id = vcpu_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 0372ed0..079dd44 100644
>> --- a/xen/arch/arm/vgic-v3-its.c
>> +++ b/xen/arch/arm/vgic-v3-its.c
>> @@ -275,8 +275,8 @@ static bool write_itte_locked(struct virt_its *its,
>> uint32_t devid,
>> * This function takes care of the locking by taking the its_lock itself, so
>> * a caller shall not hold this. Before returning, the lock is dropped
>> again.
>> */
>> -bool write_itte(struct virt_its *its, uint32_t devid, uint32_t evid,
>> - uint32_t collid, uint32_t vlpi, struct vcpu **vcpu_ptr)
>> +static bool write_itte(struct virt_its *its, uint32_t devid, uint32_t evid,
>> + uint32_t collid, uint32_t vlpi, struct vcpu
>> **vcpu_ptr)
>> {
>> bool ret;
>>
>> @@ -440,6 +440,74 @@ static int its_handle_mapd(struct virt_its *its,
>> uint64_t *cmdptr)
>> return ret;
>> }
>>
>> +static int its_handle_mapti(struct virt_its *its, uint64_t *cmdptr)
>> +{
>> + uint32_t devid = its_cmd_get_deviceid(cmdptr);
>> + uint32_t eventid = its_cmd_get_id(cmdptr);
>> + uint32_t intid = its_cmd_get_physical_id(cmdptr), _intid;
>> + uint16_t collid = its_cmd_get_collection(cmdptr);
>> + struct pending_irq *pirq;
>> + struct vcpu *vcpu = NULL;
>> + int ret = 0;
>> +
>> + if ( its_cmd_get_command(cmdptr) == GITS_CMD_MAPI )
>> + intid = eventid;
>> +
>> + spin_lock(&its->its_lock);
>> + /*
>> + * Check whether there is a valid existing mapping. If yes, behavior is
>> + * unpredictable, we choose to ignore this command here.
>> + * This makes sure we start with a pristine pending_irq below.
>> + */
>> + if ( read_itte_locked(its, devid, eventid, &vcpu, &_intid) &&
>> + _intid != INVALID_LPI )
>> + {
>> + spin_unlock(&its->its_lock);
>> + return -1;
>> + }
>> +
>> + /* Enter the mapping in our virtual ITS tables. */
>> + if ( !write_itte_locked(its, devid, eventid, collid, intid, &vcpu) )
>> + {
>> + spin_unlock(&its->its_lock);
>> + return -1;
>> + }
>> +
>> + spin_unlock(&its->its_lock);
>> +
>> + /*
>> + * Connect this virtual LPI to the corresponding host LPI, which is
>> + * determined by the same device ID and event ID on the host side.
>> + * This returns us the corresponding, still unused pending_irq.
>> + */
>> + pirq = gicv3_assign_guest_event(its->d, its->doorbell_address,
>> + devid, eventid, vcpu, intid);
>> + if ( !pirq )
>> + return -1;
>> +
>> + vgic_init_pending_irq(pirq, intid);
>> +
>> + /*
>> + * Now read the guest's property table to initialize our cached state.
>> + * It can't fire at this time, because it is not known to the host yet.
>> + */
>> + ret = update_lpi_property(its->d, intid, pirq);
>> + if ( ret )
>> + return ret;
>> +
>> + pirq->vcpu_id = vcpu->vcpu_id;
>> +
>> + /*
>> + * Now insert the pending_irq into the domain's LPI tree, so that
>> + * it becomes live.
>> + */
>> + write_lock(&its->d->arch.vgic.pend_lpi_tree_lock);
>> + radix_tree_insert(&its->d->arch.vgic.pend_lpi_tree, intid, pirq);
>> + write_unlock(&its->d->arch.vgic.pend_lpi_tree_lock);
>
> It looks like the whole allocation, starting from
> gicv3_assign_guest_event, needs to be protected by pend_lpi_tree_lock.
> Otherwise we risk allocating the same struct twice? Or that is not
> possible thanks to the vcmd_lock (because for two struct pending_irq to
> clash they need to belong to the same vits)?
Yes, the pending_irq's are allocated on MAPD, which uses an ITS and a
device ID, so this is unique. We hold the vcmd_lock, so there can't be
another command handler on this ITS.
Nevertheless I added some lines to check the return value of
radix_tree_insert, so we deal with any error here and rollback the above
actions if that fails because of ENOMEM or EEXISTS.
Cheers,
Andre.
>> + return 0;
>> +}
>> +
>> #define ITS_CMD_BUFFER_SIZE(baser) ((((baser) & 0xff) + 1) << 12)
>>
>> /*
>> @@ -480,6 +548,10 @@ static int vgic_its_handle_cmds(struct domain *d,
>> struct virt_its *its)
>> case GITS_CMD_MAPD:
>> ret = its_handle_mapd(its, command);
>> break;
>> + case GITS_CMD_MAPI:
>> + case GITS_CMD_MAPTI:
>> + ret = its_handle_mapti(its, command);
>> + break;
>> case GITS_CMD_SYNC:
>> /* We handle ITS commands synchronously, so we ignore SYNC. */
>> break;
>> diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
>> index 9b0dc3d..cb1666b 100644
>> --- a/xen/arch/arm/vgic.c
>> +++ b/xen/arch/arm/vgic.c
>> @@ -61,7 +61,7 @@ struct vgic_irq_rank *vgic_rank_irq(struct vcpu *v,
>> unsigned int irq)
>> return vgic_get_rank(v, rank);
>> }
>>
>> -static void vgic_init_pending_irq(struct pending_irq *p, unsigned int virq)
>> +void vgic_init_pending_irq(struct pending_irq *p, unsigned int virq)
>> {
>> INIT_LIST_HEAD(&p->inflight);
>> INIT_LIST_HEAD(&p->lr_queue);
>> diff --git a/xen/include/asm-arm/gic_v3_its.h
>> b/xen/include/asm-arm/gic_v3_its.h
>> index d3f393f..30aa1ef 100644
>> --- a/xen/include/asm-arm/gic_v3_its.h
>> +++ b/xen/include/asm-arm/gic_v3_its.h
>> @@ -174,6 +174,12 @@ int gicv3_its_map_guest_device(struct domain *d,
>> int gicv3_allocate_host_lpi_block(struct domain *d, uint32_t *first_lpi);
>> void gicv3_free_host_lpi_block(uint32_t first_lpi);
>>
>> +struct pending_irq *gicv3_assign_guest_event(struct domain *d, paddr_t
>> doorbell,
>> + uint32_t devid, uint32_t
>> eventid,
>> + struct vcpu *v, uint32_t
>> virt_lpi);
>> +void gicv3_lpi_update_host_entry(uint32_t host_lpi, int domain_id,
>> + unsigned int vcpu_id, uint32_t virt_lpi);
>> +
>> #else
>>
>> static LIST_HEAD(host_its_list);
>> diff --git a/xen/include/asm-arm/vgic.h b/xen/include/asm-arm/vgic.h
>> index 2371960..074afe4 100644
>> --- a/xen/include/asm-arm/vgic.h
>> +++ b/xen/include/asm-arm/vgic.h
>> @@ -83,6 +83,7 @@ struct pending_irq
>> * TODO: when implementing irq migration, taking only the current
>> * vgic lock is not going to be enough. */
>> struct list_head lr_queue;
>> + uint16_t vcpu_id; /* The VCPU for an LPI. */
>> };
>>
>> #define NR_INTERRUPT_PER_RANK 32
>> @@ -303,6 +304,7 @@ extern struct vcpu *vgic_get_target_vcpu(struct vcpu *v,
>> unsigned int virq);
>> extern void vgic_vcpu_inject_irq(struct vcpu *v, unsigned int virq);
>> extern void vgic_vcpu_inject_spi(struct domain *d, unsigned int virq);
>> extern void vgic_clear_pending_irqs(struct vcpu *v);
>> +extern void vgic_init_pending_irq(struct pending_irq *p, unsigned int virq);
>> extern struct pending_irq *irq_to_pending(struct vcpu *v, unsigned int irq);
>> extern struct pending_irq *spi_to_pending(struct domain *d, unsigned int
>> irq);
>> extern struct vgic_irq_rank *vgic_rank_offset(struct vcpu *v, int b, int n,
>> int s);
>> --
>> 2.8.2
>>
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