On 04/05/17 12:44, Eric Auger wrote:
> GITS_CREADR needs to be restored so let's implement the associated
> uaccess_write_its callback. The write only is allowed if the its
> is disabled.
> 
> Signed-off-by: Eric Auger <[email protected]>
> 
> ---
> v5 -> v6:
> - remove usage of update_64bit_reg and check alignment of cmd offset
> 
> v4 -> v5:
> - keep Stalled bit
> - vgic_mmio_uaccess_write_its_creadr can now return an error
> 
> v3 -> v4:
> - REGISTER_ITS_DESC_UACCESS now introduced in this patch
> - we now check the its is disabled
> ---
>  virt/kvm/arm/vgic/vgic-its.c | 43 +++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 41 insertions(+), 2 deletions(-)
> 
> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
> index 222fad5..18588ef 100644
> --- a/virt/kvm/arm/vgic/vgic-its.c
> +++ b/virt/kvm/arm/vgic/vgic-its.c
> @@ -1213,6 +1213,34 @@ static unsigned long vgic_mmio_read_its_creadr(struct 
> kvm *kvm,
>       return extract_bytes(its->creadr, addr & 0x7, len);
>  }
>  
> +static int vgic_mmio_uaccess_write_its_creadr(struct kvm *kvm,
> +                                           struct vgic_its *its,
> +                                           gpa_t addr, unsigned int len,
> +                                           unsigned long val)
> +{
> +     u32 cmd_offset;
> +     int ret = 0;
> +
> +     mutex_lock(&its->cmd_lock);
> +
> +     if (its->enabled) {
> +             ret = -EBUSY;
> +             goto out;
> +     }
> +
> +     cmd_offset = ITS_CMD_OFFSET(val);
> +     if ((cmd_offset >= ITS_CMD_BUFFER_SIZE(its->cbaser)) ||
> +         (cmd_offset & 0x1F)) {

nit: In general, and for alignments that aren't completely obvious, you
can write something like IS_ALIGNED(cmd_offset, sizeof(struct its_cmd)).

Unfortunately, we don't have a struct its_cmd, and maybe we should fix
that at a later time.

> +             ret = -EINVAL;
> +             goto out;
> +     }
> +
> +     its->creadr = val;
> +out:
> +     mutex_unlock(&its->cmd_lock);
> +     return ret;
> +}
> +
>  #define BASER_INDEX(addr) (((addr) / sizeof(u64)) & 0x7)
>  static unsigned long vgic_mmio_read_its_baser(struct kvm *kvm,
>                                             struct vgic_its *its,
> @@ -1317,6 +1345,16 @@ static void vgic_mmio_write_its_ctlr(struct kvm *kvm, 
> struct vgic_its *its,
>       .its_write = wr,                                        \
>  }
>  
> +#define REGISTER_ITS_DESC_UACCESS(off, rd, wr, uwr, length, acc)\
> +{                                                            \
> +     .reg_offset = off,                                      \
> +     .len = length,                                          \
> +     .access_flags = acc,                                    \
> +     .its_read = rd,                                         \
> +     .its_write = wr,                                        \
> +     .uaccess_its_write = uwr,                               \
> +}
> +
>  static void its_mmio_write_wi(struct kvm *kvm, struct vgic_its *its,
>                             gpa_t addr, unsigned int len, unsigned long val)
>  {
> @@ -1339,8 +1377,9 @@ static struct vgic_register_region its_registers[] = {
>       REGISTER_ITS_DESC(GITS_CWRITER,
>               vgic_mmio_read_its_cwriter, vgic_mmio_write_its_cwriter, 8,
>               VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
> -     REGISTER_ITS_DESC(GITS_CREADR,
> -             vgic_mmio_read_its_creadr, its_mmio_write_wi, 8,
> +     REGISTER_ITS_DESC_UACCESS(GITS_CREADR,
> +             vgic_mmio_read_its_creadr, its_mmio_write_wi,
> +             vgic_mmio_uaccess_write_its_creadr, 8,
>               VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
>       REGISTER_ITS_DESC(GITS_BASER,
>               vgic_mmio_read_its_baser, vgic_mmio_write_its_baser, 0x40,
> 

Otherwise:

Acked-by: Marc Zyngier <[email protected]>

Thanks,

        M.
-- 
Jazz is not dead. It just smells funny...
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