Re: [PATCH for-5.2 1/5] spapr/xive: Fix xive->fd if kvm_create_device() fails

[David Gibson]

On Wed, Aug 05, 2020 at 07:35:22PM +0200, Greg Kurz wrote:
> If the creation of the KVM XIVE device fails for some reasons, the
> negative errno ends up in xive->fd, but the rest of the code assumes
> that xive->fd either contains an open fd, ie. positive value, or -1.
> 
> This doesn't cause any misbehavior except kvmppc_xive_disconnect()
> that will try to close(xive->fd) during rollback and likely be
> rewarded with an EBADF.
> 
> Only set xive->fd with a open fd.
> 
> Signed-off-by: Greg Kurz <groug@kaod.org>

Applied to ppc-for-5.2.

> ---
>  hw/intc/spapr_xive_kvm.c |    8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/intc/spapr_xive_kvm.c b/hw/intc/spapr_xive_kvm.c
> index edb7ee0e74f1..d55ea4670e0e 100644
> --- a/hw/intc/spapr_xive_kvm.c
> +++ b/hw/intc/spapr_xive_kvm.c
> @@ -745,6 +745,7 @@ int kvmppc_xive_connect(SpaprInterruptController *intc, 
> uint32_t nr_servers,
>      size_t esb_len = (1ull << xsrc->esb_shift) * xsrc->nr_irqs;
>      size_t tima_len = 4ull << TM_SHIFT;
>      CPUState *cs;
> +    int fd;
>  
>      /*
>       * The KVM XIVE device already in use. This is the case when
> @@ -760,11 +761,12 @@ int kvmppc_xive_connect(SpaprInterruptController *intc, 
> uint32_t nr_servers,
>      }
>  
>      /* First, create the KVM XIVE device */
> -    xive->fd = kvm_create_device(kvm_state, KVM_DEV_TYPE_XIVE, false);
> -    if (xive->fd < 0) {
> -        error_setg_errno(errp, -xive->fd, "XIVE: error creating KVM device");
> +    fd = kvm_create_device(kvm_state, KVM_DEV_TYPE_XIVE, false);
> +    if (fd < 0) {
> +        error_setg_errno(errp, -fd, "XIVE: error creating KVM device");
>          return -1;
>      }
> +    xive->fd = fd;
>  
>      /* Tell KVM about the # of VCPUs we may have */
>      if (kvm_device_check_attr(xive->fd, KVM_DEV_XIVE_GRP_CTRL,
> 
> 

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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