Re: [PATCH v5 11/22] KVM: arm64: vgic-its: Interpret MAPD Size field and check related errors

Christoffer Dall
2017-04-27T16:25:31Z

On Fri, Apr 14, 2017 at 12:15:23PM +0200, Eric Auger wrote:
> Up to now the MAPD's ITT size field has been ignored. It encodes
> the number of eventid bit minus 1. It should be used to check
> the eventid when a MAPTI command is issued on a device. Let's
> store the number of eventid bits in the its_device and do the
> check on MAPTI. Also make sure the ITT size field does
> not exceed the GITS_TYPER IDBITS field.
>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>
> ---
> v4 -> v5:
> - its_cmd_get_size macro now returns the actual number of eventid bits
> - use GIC_ENCODE_SZ macro to encode ID_bits
>
> v3 -> v4:
> - VITS_TYPER_IDBITS set to 16 to be homogeneous with VITS_ESZ definition
> and correct users
> - nb_eventid_bits correspond to the actual number of eventid bits
> ---
> include/linux/irqchip/arm-gic-v3.h | 2 ++
> virt/kvm/arm/vgic/vgic-its.c | 15 ++++++++++++++-
> 2 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
> index 54c20bd..0c6798c 100644
> --- a/include/linux/irqchip/arm-gic-v3.h
> +++ b/include/linux/irqchip/arm-gic-v3.h
> @@ -345,9 +345,11 @@
> #define E_ITS_INT_UNMAPPED_INTERRUPT 0x010307
> #define E_ITS_CLEAR_UNMAPPED_INTERRUPT 0x010507
> #define E_ITS_MAPD_DEVICE_OOR 0x010801
> +#define E_ITS_MAPD_ITTSIZE_OOR 0x010802
> #define E_ITS_MAPC_PROCNUM_OOR 0x010902
> #define E_ITS_MAPC_COLLECTION_OOR 0x010903
> #define E_ITS_MAPTI_UNMAPPED_DEVICE 0x010a04
> +#define E_ITS_MAPTI_ID_OOR 0x010a05
> #define E_ITS_MAPTI_PHYSICALID_OOR 0x010a06
> #define E_ITS_INV_UNMAPPED_INTERRUPT 0x010c07
> #define E_ITS_INVALL_UNMAPPED_COLLECTION 0x010d09
> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
> index 1b5797e..0f3c8f3 100644
> --- a/virt/kvm/arm/vgic/vgic-its.c
> +++ b/virt/kvm/arm/vgic/vgic-its.c
> @@ -105,6 +105,7 @@ struct its_device {
>
> /* the head for the list of ITTEs */
> struct list_head itt_head;
> + u32 nb_eventid_bits;

what does nb_ mean?

> u32 device_id;
> };
>
> @@ -191,6 +192,8 @@ static struct its_ite *find_ite(struct vgic_its *its, u32 device_id,
>
> #define GIC_LPI_OFFSET 8192
>
> +#define VITS_TYPER_IDBITS 16
> +
> /*
> * Finds and returns a collection in the ITS collection table.
> * Must be called with the its_lock mutex held.
> @@ -391,7 +394,7 @@ static unsigned long vgic_mmio_read_its_typer(struct kvm *kvm,
> * DevBits low - as least for the time being.
> */
> reg |= 0x0f << GITS_TYPER_DEVBITS_SHIFT;
> - reg |= 0x0f << GITS_TYPER_IDBITS_SHIFT;
> + reg |= GIC_ENCODE_SZ(VITS_TYPER_IDBITS, 5) << GITS_TYPER_IDBITS_SHIFT;
> reg |= GIC_ENCODE_SZ(abi->ite_esz, 4) << GITS_TYPER_ITT_ENTRY_SIZE_SHIFT;
>
> return extract_bytes(reg, addr & 7, len);
> @@ -562,6 +565,7 @@ static u64 its_cmd_mask_field(u64 *its_cmd, int word, int shift, int size)
>
> #define its_cmd_get_command(cmd) its_cmd_mask_field(cmd, 0, 0, 8)
> #define its_cmd_get_deviceid(cmd) its_cmd_mask_field(cmd, 0, 32, 32)
> +#define its_cmd_get_size(cmd) (its_cmd_mask_field(cmd, 1, 0, 5) + 1)
> #define its_cmd_get_id(cmd) its_cmd_mask_field(cmd, 1, 0, 32)
> #define its_cmd_get_physical_id(cmd) its_cmd_mask_field(cmd, 1, 32, 32)
> #define its_cmd_get_collection(cmd) its_cmd_mask_field(cmd, 2, 0, 16)
> @@ -752,6 +756,9 @@ static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its,
> if (!device)
> return E_ITS_MAPTI_UNMAPPED_DEVICE;
>
> + if (event_id >= BIT_ULL(device->nb_eventid_bits))
> + return E_ITS_MAPTI_ID_OOR;
> +
> if (its_cmd_get_command(its_cmd) == GITS_CMD_MAPTI)
> lpi_nr = its_cmd_get_physical_id(its_cmd);
> else
> @@ -832,11 +839,15 @@ static int vgic_its_cmd_handle_mapd(struct kvm *kvm, struct vgic_its *its,
> {
> u32 device_id = its_cmd_get_deviceid(its_cmd);
> bool valid = its_cmd_get_validbit(its_cmd);
> + u8 nb_eventid_bits = its_cmd_get_size(its_cmd);
> struct its_device *device;
>
> if (!vgic_its_check_id(its, its->baser_device_table, device_id))
> return E_ITS_MAPD_DEVICE_OOR;
>
> + if (valid && nb_eventid_bits > VITS_TYPER_IDBITS)
> + return E_ITS_MAPD_ITTSIZE_OOR;
> +
> device = find_its_device(its, device_id);
>
> /*
> @@ -859,6 +870,8 @@ static int vgic_its_cmd_handle_mapd(struct kvm *kvm, struct vgic_its *its,
> return -ENOMEM;
>
> device->device_id = device_id;
> + device->nb_eventid_bits = nb_eventid_bits;
> +
> INIT_LIST_HEAD(&device->itt_head);
>
> list_add_tail(&device->dev_list, &its->device_list);
> --
> 2.5.5
>

Otherwise:

Reviewed-by: Christoffer Dall <cdall@linaro.org>