[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v8 15/27] ARM: vITS: handle CLEAR command
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. As read_itte() is now eventually used, we add the static keyword. Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx> --- xen/arch/arm/vgic-v3-its.c | 52 ++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 50 insertions(+), 2 deletions(-) diff --git a/xen/arch/arm/vgic-v3-its.c b/xen/arch/arm/vgic-v3-its.c index 632ab84..e24ab60 100644 --- a/xen/arch/arm/vgic-v3-its.c +++ b/xen/arch/arm/vgic-v3-its.c @@ -227,8 +227,8 @@ static bool read_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 read_itte(struct virt_its *its, uint32_t devid, uint32_t evid, - struct vcpu **vcpu_ptr, uint32_t *vlpi_ptr) +static bool read_itte(struct virt_its *its, uint32_t devid, uint32_t evid, + struct vcpu **vcpu_ptr, uint32_t *vlpi_ptr) { bool ret; @@ -297,6 +297,51 @@ static uint64_t its_cmd_mask_field(uint64_t *its_cmd, unsigned int word, #define its_cmd_get_validbit(cmd) its_cmd_mask_field(cmd, 2, 63, 1) #define its_cmd_get_ittaddr(cmd) (its_cmd_mask_field(cmd, 2, 8, 44) << 8) +/* + * CLEAR removes the pending state from an LPI. */ +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 *p; + struct vcpu *vcpu; + uint32_t vlpi; + unsigned long flags; + + /* Translate the DevID/EvID pair into a vCPU/vLPI pair. */ + if ( !read_itte(its, devid, eventid, &vcpu, &vlpi) ) + return -1; + + spin_lock_irqsave(&vcpu->arch.vgic.lock, flags); + + p = its->d->arch.vgic.handler->lpi_to_pending(its->d, vlpi); + if ( !p ) + { + spin_unlock_irqrestore(&vcpu->arch.vgic.lock, flags); + return -1; + } + + /* + * If the LPI is already visible on the guest, it is too late to + * clear the pending state. However this is a benign race that can + * happen on real hardware, too: If the LPI has already been forwarded + * to a CPU interface, a CLEAR request reaching the redistributor has + * no effect on that LPI anymore. Since LPIs are edge triggered and + * have no active state, we don't need to care about this here. + */ + if ( !test_bit(GIC_IRQ_GUEST_VISIBLE, &p->status) ) + { + /* Remove a pending, but not yet injected guest IRQ. */ + clear_bit(GIC_IRQ_GUEST_QUEUED, &p->status); + list_del_init(&p->inflight); + list_del_init(&p->lr_queue); + } + + spin_unlock_irqrestore(&vcpu->arch.vgic.lock, flags); + + return 0; +} + #define ITS_CMD_BUFFER_SIZE(baser) ((((baser) & 0xff) + 1) << 12) #define ITS_CMD_OFFSET(reg) ((reg) & GENMASK(19, 5)) @@ -326,6 +371,9 @@ static int vgic_its_handle_cmds(struct domain *d, struct virt_its *its) switch ( its_cmd_get_command(command) ) { + case GITS_CMD_CLEAR: + ret = its_handle_clear(its, command); + break; case GITS_CMD_SYNC: /* We handle ITS commands synchronously, so we ignore SYNC. */ break; -- 2.8.2 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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