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KVM: PPC: Book3S HV: XIVE: Set kvm->arch.xive when VPs are allocated 

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: 5422e95103 ("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>
alistair/sunxi64-5.5-dsi
Greg Kurz 2019-09-27 13:53:38 +02:00 committed by Paul Mackerras
parent f41c4989c8
commit e7d71c9430
2 changed files with 6 additions and 7 deletions
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11
arch/powerpc/kvm/book3s_xive.c
View File

@ -2005,6 +2005,10 @@ 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)
@ -2039,6 +2037,7 @@ static int kvmppc_xive_create(struct kvm_device *dev, u32 type)
if (ret)
return ret;
kvm->arch.xive = xive;
return 0;
}

2
arch/powerpc/kvm/book3s_xive_native.c
View File

@ -1081,7 +1081,6 @@ static int kvmppc_xive_native_create(struct kvm_device *dev, u32 type)
dev->private = xive;
xive->dev = dev;
xive->kvm = kvm;
kvm->arch.xive = xive;
mutex_init(&xive->mapping_lock);
mutex_init(&xive->lock);
@ -1102,6 +1101,7 @@ static int kvmppc_xive_native_create(struct kvm_device *dev, u32 type)
if (ret)
return ret;
kvm->arch.xive = xive;
return 0;
}