lkml.org 
[lkml]   [2019]   [Dec]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.3 078/105] KVM: PPC: Book3S HV: XIVE: Set kvm->arch.xive when VPs are allocated
    Date
    From: Greg Kurz <groug@kaod.org>

    commit e7d71c943040c23f2fd042033d319f56e84f845b upstream.

    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 release method isn't called in this case. Any
    subsequent tentative to create a XIVE or XICS-on-XIVE for this VM will
    thus always fail (DoS). 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 much slower 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.

    Cc: stable@vger.kernel.org # v5.2
    Fixes: 5422e95103cf ("KVM: PPC: Book3S HV: XIVE: Replace the 'destroy' method by a 'release' method")
    Signed-off-by: Greg Kurz <groug@kaod.org>
    Reviewed-by: Cédric Le Goater <clg@kaod.org>
    Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    arch/powerpc/kvm/book3s_xive.c | 11 +++++------
    arch/powerpc/kvm/book3s_xive_native.c | 2 +-
    2 files changed, 6 insertions(+), 7 deletions(-)

    --- a/arch/powerpc/kvm/book3s_xive.c
    +++ b/arch/powerpc/kvm/book3s_xive.c
    @@ -2005,6 +2005,10 @@ static int kvmppc_xive_create(struct kvm

    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
    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)
    @@ -2039,6 +2037,7 @@ static int kvmppc_xive_create(struct kvm
    if (ret)
    return ret;

    + kvm->arch.xive = xive;
    return 0;
    }

    --- a/arch/powerpc/kvm/book3s_xive_native.c
    +++ b/arch/powerpc/kvm/book3s_xive_native.c
    @@ -1095,7 +1095,6 @@ static int kvmppc_xive_native_create(str
    dev->private = xive;
    xive->dev = dev;
    xive->kvm = kvm;
    - kvm->arch.xive = xive;
    mutex_init(&xive->mapping_lock);
    mutex_init(&xive->lock);

    @@ -1116,6 +1115,7 @@ static int kvmppc_xive_native_create(str
    if (ret)
    return ret;

    + kvm->arch.xive = xive;
    return 0;
    }


    \
     
     \ /
      Last update: 2019-12-11 16:57    [W:4.031 / U:0.072 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site