On 23/09/2019 17:43, Greg Kurz wrote:
> If we cannot allocate the XIVE VPs in OPAL, the creation of a XIVE or
> XICS-on-XIVE device is aborted as expected, but we leave kvm->arch.xive
> set forever since the relase method isn't called in this case. Any
release
> subsequent tentative to create a XIVE or XICS-on-XIVE for this VM will
> thus always fail. This is a problem for QEMU since it destroys and
> re-creates these devices when the VM is reset: the VM would be
> restricted to using the emulated XIVE or XICS forever.
>
> As an alternative to adding rollback, do not assign kvm->arch.xive before
> making sure the XIVE VPs are allocated in OPAL.
>
> Fixes: 5422e95103cf ("KVM: PPC: Book3S HV: XIVE: Replace the 'destroy' method by a 'release' method")
> Signed-off-by: Greg Kurz <groug@xxxxxxxx>
Reviewed-by: Cédric Le Goater <clg@xxxxxxxx>
C.
> ---
> arch/powerpc/kvm/book3s_xive.c | 11 +++++------
> arch/powerpc/kvm/book3s_xive_native.c | 2 +-
> 2 files changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c
> index cd2006bfcd3e..2ef43d037a4f 100644
> --- a/arch/powerpc/kvm/book3s_xive.c
> +++ b/arch/powerpc/kvm/book3s_xive.c
> @@ -2006,6 +2006,10 @@ static int kvmppc_xive_create(struct kvm_device *dev, u32 type)
>
> pr_devel("Creating xive for partition\n");
>
> + /* Already there ? */
> + if (kvm->arch.xive)
> + return -EEXIST;
> +
> xive = kvmppc_xive_get_device(kvm, type);
> if (!xive)
> return -ENOMEM;
> @@ -2014,12 +2018,6 @@ static int kvmppc_xive_create(struct kvm_device *dev, u32 type)
> xive->kvm = kvm;
> mutex_init(&xive->lock);
>
> - /* Already there ? */
> - if (kvm->arch.xive)
> - ret = -EEXIST;
> - else
> - kvm->arch.xive = xive;
> -
> /* We use the default queue size set by the host */
> xive->q_order = xive_native_default_eq_shift();
> if (xive->q_order < PAGE_SHIFT)
> @@ -2040,6 +2038,7 @@ static int kvmppc_xive_create(struct kvm_device *dev, u32 type)
> return ret;
>
> dev->private = xive;
> + kvm->arch.xive = xive;
> return 0;
> }
>
> diff --git a/arch/powerpc/kvm/book3s_xive_native.c b/arch/powerpc/kvm/book3s_xive_native.c
> index e9cbb42de424..84a354b90f60 100644
> --- a/arch/powerpc/kvm/book3s_xive_native.c
> +++ b/arch/powerpc/kvm/book3s_xive_native.c
> @@ -1087,7 +1087,6 @@ static int kvmppc_xive_native_create(struct kvm_device *dev, u32 type)
>
> xive->dev = dev;
> xive->kvm = kvm;
> - kvm->arch.xive = xive;
> mutex_init(&xive->mapping_lock);
> mutex_init(&xive->lock);
>
> @@ -1109,6 +1108,7 @@ static int kvmppc_xive_native_create(struct kvm_device *dev, u32 type)
> return ret;
>
> dev->private = xive;
> + kvm->arch.xive = xive;
> return 0;
> }
>
>
