KVM: PPC: Book3S HV: XIVE: Set kvm->arch.xive when VPs are allocated (e7d71c94) · Commits · 戴 / test

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: ("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>

arch/powerpc/kvm/book3s_xive.c

+5 −6

Original line number	Diff line number	Diff line
		@@ -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;
		}

arch/powerpc/kvm/book3s_xive_native.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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;
		}

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