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SubjectRe: [patch] kvm: suppress KVM_SET_GSI_ROUTING allocation failure
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On 02/08/2018 10:35 PM, David Rientjes wrote:
> The KVM_SET_GSI_ROUTING ioctl does a vmalloc() of
> sizeof(struct kvm_irq_routing_entry) multiplied by a user-supplied value.
> This can be up to 4096 entries on architectures such as arm64 and s390
> (and the upper bound may be increased on s390 eventually).
>
> This can produce a vmalloc allocation failure warning:
>
[...]
> kvm_vm_ioctl+0x910/0x15e0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:4153

^^^^^

> @@ -3063,7 +3063,8 @@ static long kvm_vm_ioctl(struct file *filp,

^^^^^


Are you sure that you got the right vmalloc?


> goto out;
> if (routing.nr) {
> r = -ENOMEM;
> - entries = vmalloc(routing.nr * sizeof(*entries));
> + entries = __vmalloc(routing.nr * sizeof(*entries),
> + GFP_KERNEL | __GFP_NOWARN, PAGE_KERNEL);
> if (!entries)
> goto out;
> r = -EFAULT;
>
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