This introduces the ITS command handler for the CLEAR command, which clears the pending state of an LPI. This removes a not-yet injected, but already queued IRQ from a VCPU.
In addition this patch introduces the lookup function which translates a given DeviceID/EventID pair into a pointer to our vITTE structure. Signed-off-by: Andre Przywara <andre.przyw...@arm.com> --- xen/arch/arm/vgic-its.c | 115 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 115 insertions(+) diff --git a/xen/arch/arm/vgic-its.c b/xen/arch/arm/vgic-its.c index 875b992..99d9e9c 100644 --- a/xen/arch/arm/vgic-its.c +++ b/xen/arch/arm/vgic-its.c @@ -61,6 +61,73 @@ struct vits_itte uint64_t collection:16; }; +#define UNMAPPED_COLLECTION ((uint16_t)~0) + +/* Must be called with the ITS lock held. */ +static struct vcpu *get_vcpu_from_collection(struct virt_its *its, int collid) +{ + uint16_t vcpu_id; + + if ( collid >= its->max_collections ) + return NULL; + + vcpu_id = its->coll_table[collid]; + if ( vcpu_id == UNMAPPED_COLLECTION || vcpu_id >= its->d->max_vcpus ) + return NULL; + + return its->d->vcpu[vcpu_id]; +} + +#define DEV_TABLE_ITT_ADDR(x) ((x) & GENMASK(51, 8)) +#define DEV_TABLE_ITT_SIZE(x) (BIT(((x) & GENMASK(7, 0)) + 1)) +#define DEV_TABLE_ENTRY(addr, bits) \ + (((addr) & GENMASK(51, 8)) | (((bits) - 1) & GENMASK(7, 0))) + +static paddr_t get_itte_address(struct virt_its *its, + uint32_t devid, uint32_t evid) +{ + paddr_t addr; + + if ( devid >= its->max_devices ) + return ~0; + + if ( evid >= DEV_TABLE_ITT_SIZE(its->dev_table[devid]) ) + return ~0; + + addr = DEV_TABLE_ITT_ADDR(its->dev_table[devid]); + + return addr + evid * sizeof(struct vits_itte); +} + +/* Looks up a given deviceID/eventID pair on an ITS and returns a pointer to + * the corresponding ITTE. This maps the respective guest page into Xen. + * Once finished with handling the ITTE, call put_devid_evid() to unmap + * the page again. + * Must be called with the ITS lock held. + */ +static struct vits_itte *get_devid_evid(struct virt_its *its, + uint32_t devid, uint32_t evid) +{ + paddr_t addr = get_itte_address(its, devid, evid); + struct vits_itte *itte; + + if (addr == ~0) + return NULL; + + /* TODO: check locking for map_guest_pages() */ + itte = map_guest_pages(its->d, addr & PAGE_MASK, 1); + if ( !itte ) + return NULL; + + return itte + (addr & ~PAGE_MASK) / sizeof(struct vits_itte); +} + +/* Must be called with the ITS lock held. */ +static void put_devid_evid(struct virt_its *its, struct vits_itte *itte) +{ + unmap_guest_pages(itte, 1); +} + /************************************** * Functions that handle ITS commands * **************************************/ @@ -80,6 +147,51 @@ static uint64_t its_cmd_mask_field(uint64_t *its_cmd, #define its_cmd_get_target_addr(cmd) its_cmd_mask_field(cmd, 2, 16, 32) #define its_cmd_get_validbit(cmd) its_cmd_mask_field(cmd, 2, 63, 1) +static int its_handle_clear(struct virt_its *its, uint64_t *cmdptr) +{ + uint32_t devid = its_cmd_get_deviceid(cmdptr); + uint32_t eventid = its_cmd_get_id(cmdptr); + struct pending_irq *pirq; + struct vits_itte *itte; + struct vcpu *vcpu; + uint32_t vlpi; + + spin_lock(&its->its_lock); + + itte = get_devid_evid(its, devid, eventid); + if ( !itte ) + { + spin_unlock(&its->its_lock); + return -1; + } + + vcpu = get_vcpu_from_collection(its, itte->collection); + if ( !vcpu ) + { + spin_unlock(&its->its_lock); + return -1; + } + + vlpi = itte->vlpi; + + put_devid_evid(its, itte); + spin_unlock(&its->its_lock); + + /* Remove a pending, but not yet injected guest IRQ. */ + pirq = lpi_to_pending(vcpu, vlpi, false); + if ( pirq ) + { + clear_bit(GIC_IRQ_GUEST_QUEUED, &pirq->status); + gic_remove_from_queues(vcpu, vlpi); + + /* Mark this pending IRQ struct as availabe again. */ + if ( !test_bit(GIC_IRQ_GUEST_VISIBLE, &pirq->status) ) + pirq->irq = 0; + } + + return 0; +} + #define ITS_CMD_BUFFER_SIZE(baser) ((((baser) & 0xff) + 1) << 12) static int vgic_its_handle_cmds(struct domain *d, struct virt_its *its, @@ -100,6 +212,9 @@ static int vgic_its_handle_cmds(struct domain *d, struct virt_its *its, cmdptr = its->cmdbuf + (its->creadr / sizeof(*its->cmdbuf)); switch (its_cmd_get_command(cmdptr)) { + case GITS_CMD_CLEAR: + its_handle_clear(its, cmdptr); + break; case GITS_CMD_SYNC: /* We handle ITS commands synchronously, so we ignore SYNC. */ break; -- 2.9.0 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel