Re: [PATCH v6 13/24] KVM: arm64: vgic-its: Check the device id matches TYPER DEVBITS range

Christoffer Dall
2017-05-04T17:19:26Z

On Thu, May 04, 2017 at 01:44:33PM +0200, Eric Auger wrote:
> On MAPD we currently check the device id can be stored in the device table.
> Let's first check it can be encoded within the range defined by TYPER
> DEVBITS.
>
> Also check the collection ID belongs to the 16 bit range as GITS_TYPER
> CIL field equals to 0.
>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>
> ---
>
> v4 -> v5:
> - use GIC_ENCODE_SZ macro
>
> v3 -> v4:
> - VITS_TYPER_DEVBITS set to 16 for homogeneity
> - use BIT_ULL
> ---
> virt/kvm/arm/vgic/vgic-its.c | 25 ++++++++++++++++++++-----
> 1 file changed, 20 insertions(+), 5 deletions(-)
>
> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
> index 6da548d..e7bb86a 100644
> --- a/virt/kvm/arm/vgic/vgic-its.c
> +++ b/virt/kvm/arm/vgic/vgic-its.c
> @@ -204,6 +204,7 @@ static struct its_ite *find_ite(struct vgic_its *its, u32 device_id,
> #define GIC_LPI_OFFSET 8192
>
> #define VITS_TYPER_IDBITS 16
> +#define VITS_TYPER_DEVBITS 16
>
> /*
> * Finds and returns a collection in the ITS collection table.
> @@ -404,7 +405,7 @@ static unsigned long vgic_mmio_read_its_typer(struct kvm *kvm,
> * To avoid memory waste in the guest, we keep the number of IDBits and
> * DevBits low - as least for the time being.
> */
> - reg |= 0x0f << GITS_TYPER_DEVBITS_SHIFT;
> + reg |= GIC_ENCODE_SZ(VITS_TYPER_DEVBITS, 5) << GITS_TYPER_DEVBITS_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;
>
> @@ -646,16 +647,30 @@ static int vgic_its_cmd_handle_movi(struct kvm *kvm, struct vgic_its *its,
> * Check whether an ID can be stored into the corresponding guest table.
> * For a direct table this is pretty easy, but gets a bit nasty for
> * indirect tables. We check whether the resulting guest physical address
> - * is actually valid (covered by a memslot and guest accessbible).
> + * is actually valid (covered by a memslot and guest accessible).
> * For this we have to read the respective first level entry.
> */
> -static bool vgic_its_check_id(struct vgic_its *its, u64 baser, int id)
> +static bool vgic_its_check_id(struct vgic_its *its, u64 baser, u32 id)
> {
> int l1_tbl_size = GITS_BASER_NR_PAGES(baser) * SZ_64K;
> + u64 indirect_ptr, type = GITS_BASER_TYPE(baser);
> + int esz = GITS_BASER_ENTRY_SIZE(baser);
> int index;
> - u64 indirect_ptr;
> gfn_t gfn;
> - int esz = GITS_BASER_ENTRY_SIZE(baser);
> +
> + switch (type) {
> + case GITS_BASER_TYPE_DEVICE:
> + if (id >= BIT_ULL(VITS_TYPER_DEVBITS))
> + return false;
> + break;
> + case GITS_BASER_TYPE_COLLECTION:
> + /* as GITS_TYPER.CID == 0, ITS supports 16-bit collection ID */

nit: GITS_TYPE.CIL

> + if (id >= BIT_ULL(16))
> + return false;
> + break;
> + default:
> + return false;
> + }
>
> if (!(baser & GITS_BASER_INDIRECT)) {
> phys_addr_t addr;
> --
> 2.5.5
>

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