On Tue, Oct 17, 2017 at 09:10:04AM +0200, Eric Auger wrote:
> At the moment vgic_its_process_commands() does not
> check the CBASER is valid before processing any command.
> Let's fix that.
> 
> Also rename cbaser local variable into cbaser_pa to avoid
> any confusion with the full register.
> 
> Signed-off-by: Eric Auger <eric.au...@redhat.com>
> ---
>  virt/kvm/arm/vgic/vgic-its.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
> index 3b539d4..e18f1e4 100644
> --- a/virt/kvm/arm/vgic/vgic-its.c
> +++ b/virt/kvm/arm/vgic/vgic-its.c
> @@ -1301,17 +1301,20 @@ static void vgic_mmio_write_its_cbaser(struct kvm 
> *kvm, struct vgic_its *its,
>  /* Must be called with the cmd_lock held. */
>  static void vgic_its_process_commands(struct kvm *kvm, struct vgic_its *its)
>  {
> -     gpa_t cbaser;
> +     gpa_t cbaser_pa;
>       u64 cmd_buf[4];
>  
> -     /* Commands are only processed when the ITS is enabled. */
> -     if (!its->enabled)
> +     /*
> +      * Commands are only processed when the ITS is enabled and
> +      * CBASER is valid
> +      */
> +     if (!its->enabled || (!(its->cbaser & GITS_CBASER_VALID)))

Is it valid to clear the CBASER valid bit after having enabled the ITS?
If not, I think you should check changes to CBASER and then this
shouldn't be necessary.



>               return;
>  
> -     cbaser = CBASER_ADDRESS(its->cbaser);
> +     cbaser_pa = CBASER_ADDRESS(its->cbaser);
>  
>       while (its->cwriter != its->creadr) {
> -             int ret = kvm_read_guest(kvm, cbaser + its->creadr,
> +             int ret = kvm_read_guest(kvm, cbaser_pa + its->creadr,
>                                        cmd_buf, ITS_CMD_SIZE);
>               /*
>                * If kvm_read_guest() fails, this could be due to the guest
> -- 
> 2.5.5
> 

Otherwise, this looks fine.

Thanks,
-Christoffer

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