Re: [Xen-devel] [RFC PATCH 17/24] ARM: vITS: handle MAPTI command

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 28 Sep 2016, Andre Przywara wrote:
> The MAPTI commands associates a DeviceID/EventID pair with a LPI/CPU
> pair and actually instantiates LPI interrupts.
> We allocate a new host LPI and connect that one to this virtual LPI,
> so that any triggering IRQ on the host can be quickly forwarded to
> a guest.
> 
> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
> ---
>  xen/arch/arm/vgic-its.c | 53 
> +++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 53 insertions(+)
> 
> diff --git a/xen/arch/arm/vgic-its.c b/xen/arch/arm/vgic-its.c
> index 83d47e1..70897dd 100644
> --- a/xen/arch/arm/vgic-its.c
> +++ b/xen/arch/arm/vgic-its.c
> @@ -278,6 +278,55 @@ static int its_handle_mapd(struct virt_its *its, 
> uint64_t *cmdptr)
>      return 0;
>  }
>  
> +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);
> +    int collid = its_cmd_get_collection(cmdptr);
> +    struct vits_itte *itte;
> +    uint32_t host_lpi;
> +    struct vcpu *vcpu;
> +    int ret = -1;
> +
> +    if ( its_cmd_get_command(cmdptr) == GITS_CMD_MAPI )
> +        intid = eventid;
> +
> +    if ( collid >= its->max_collections )
> +        return -1;
> +
> +    spin_lock(&its->its_lock);
> +    vcpu = get_vcpu_from_collection(its, collid);
> +    if ( !vcpu )
> +        goto out_unlock;
> +
> +    itte = get_devid_evid(its, devid, eventid);
> +    if ( !itte )
> +        goto out_unlock;
> +
> +    if ( itte->hlpi )
> +        goto out_unmap;

get_vcpu_from_collection and get_devid_evid take care of checking the
validity of devid, eventid and collid. Do we need to also check that
devid, eventid and intid are valid from a host perspective, given that
we are calling gicv3_lpi_allocate_host_lpi?


> +    host_lpi = gicv3_lpi_allocate_host_lpi(its->hw_its,
> +                                           devid, eventid,
> +                                           vcpu, intid);
> +    if ( host_lpi >= 0 )
> +        itte->hlpi = host_lpi;
> +
> +    itte->vlpi = intid;
> +    itte->collection = collid;
> +
> +    ret = 0;
> +
> +out_unmap:
> +    put_devid_evid(its, itte);
> +
> +out_unlock:
> +    spin_unlock(&its->its_lock);
> +    
> +    return ret;
> +}
> +
>  #define ITS_CMD_BUFFER_SIZE(baser)      ((((baser) & 0xff) + 1) << 12)
>  
>  static int vgic_its_handle_cmds(struct domain *d, struct virt_its *its,
> @@ -310,6 +359,10 @@ static int vgic_its_handle_cmds(struct domain *d, struct 
> virt_its *its,
>          case GITS_CMD_MAPD:
>              its_handle_mapd(its, cmdptr);
>           break;
> +        case GITS_CMD_MAPI:
> +        case GITS_CMD_MAPTI:
> +            its_handle_mapti(its, cmdptr);
> +            break;
>          case GITS_CMD_SYNC:
>              /* We handle ITS commands synchronously, so we ignore SYNC. */
>           break;
> -- 
> 2.9.0
> 

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