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Re: [Qemu-devel] [PATCH] Qemu/Xen: Fix early freeing MSIX MMIO memory re
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH] Qemu/Xen: Fix early freeing MSIX MMIO memory region |
Date: |
Mon, 12 Oct 2015 14:01:22 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 |
On 12/10/2015 13:09, Stefano Stabellini wrote:
> On Sun, 11 Oct 2015, Lan Tianyu wrote:
>> From: <address@hidden>>
>>
>> msix->mmio is added to XenPCIPassthroughState's object as property.
>> object_finalize_child_property is called for XenPCIPassthroughState's
>> object, which calls object_property_del_all, which is going to try to
>> delete msix->mmio. object_finalize_child_property() will access
>> msix->mmio's obj. But the whole msix struct has already been freed
>> by xen_pt_msix_delete. This will cause segment fault when msix->mmio
>> has been overwritten.
>>
>> This patch is to fix the issue.
>>
>> Signed-off-by: Lan Tianyu <address@hidden>
>
> Looks good to me. Paolo?
Also looks good to me. Thanks!
Paolo
>> hw/xen/xen_pt.c | 8 ++++++++
>> hw/xen/xen_pt.h | 1 +
>> hw/xen/xen_pt_config_init.c | 2 +-
>> hw/xen/xen_pt_msi.c | 13 ++++++++++++-
>> 4 files changed, 22 insertions(+), 2 deletions(-)
>>
>> diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c
>> index 2b54f52..aa96288 100644
>> --- a/hw/xen/xen_pt.c
>> +++ b/hw/xen/xen_pt.c
>> @@ -938,10 +938,18 @@ static void xen_pci_passthrough_class_init(ObjectClass
>> *klass, void *data)
>> dc->props = xen_pci_passthrough_properties;
>> };
>>
>> +static void xen_pci_passthrough_finalize(Object *obj)
>> +{
>> + XenPCIPassthroughState *s = XEN_PT_DEVICE(obj);
>> +
>> + xen_pt_msix_delete(s);
>> +}
>> +
>> static const TypeInfo xen_pci_passthrough_info = {
>> .name = TYPE_XEN_PT_DEVICE,
>> .parent = TYPE_PCI_DEVICE,
>> .instance_size = sizeof(XenPCIPassthroughState),
>> + .instance_finalize = xen_pci_passthrough_finalize,
>> .class_init = xen_pci_passthrough_class_init,
>> };
>>
>> diff --git a/hw/xen/xen_pt.h b/hw/xen/xen_pt.h
>> index 3bc22eb..c545280 100644
>> --- a/hw/xen/xen_pt.h
>> +++ b/hw/xen/xen_pt.h
>> @@ -305,6 +305,7 @@ void xen_pt_msi_disable(XenPCIPassthroughState *s);
>>
>> int xen_pt_msix_init(XenPCIPassthroughState *s, uint32_t base);
>> void xen_pt_msix_delete(XenPCIPassthroughState *s);
>> +void xen_pt_msix_unmap(XenPCIPassthroughState *s);
>> int xen_pt_msix_update(XenPCIPassthroughState *s);
>> int xen_pt_msix_update_remap(XenPCIPassthroughState *s, int bar_index);
>> void xen_pt_msix_disable(XenPCIPassthroughState *s);
>> diff --git a/hw/xen/xen_pt_config_init.c b/hw/xen/xen_pt_config_init.c
>> index 4a5bc11..0efee11 100644
>> --- a/hw/xen/xen_pt_config_init.c
>> +++ b/hw/xen/xen_pt_config_init.c
>> @@ -2079,7 +2079,7 @@ void xen_pt_config_delete(XenPCIPassthroughState *s)
>>
>> /* free MSI/MSI-X info table */
>> if (s->msix) {
>> - xen_pt_msix_delete(s);
>> + xen_pt_msix_unmap(s);
>> }
>> g_free(s->msi);
>>
>> diff --git a/hw/xen/xen_pt_msi.c b/hw/xen/xen_pt_msi.c
>> index e3d7194..82de2bc 100644
>> --- a/hw/xen/xen_pt_msi.c
>> +++ b/hw/xen/xen_pt_msi.c
>> @@ -610,7 +610,7 @@ error_out:
>> return rc;
>> }
>>
>> -void xen_pt_msix_delete(XenPCIPassthroughState *s)
>> +void xen_pt_msix_unmap(XenPCIPassthroughState *s)
>> {
>> XenPTMSIX *msix = s->msix;
>>
>> @@ -627,6 +627,17 @@ void xen_pt_msix_delete(XenPCIPassthroughState *s)
>> }
>>
>> memory_region_del_subregion(&s->bar[msix->bar_index], &msix->mmio);
>> +}
>> +
>> +void xen_pt_msix_delete(XenPCIPassthroughState *s)
>> +{
>> + XenPTMSIX *msix = s->msix;
>> +
>> + if (!msix) {
>> + return;
>> + }
>> +
>> + object_unparent(OBJECT(&msix->mmio));
>>
>> g_free(s->msix);
>> s->msix = NULL;
>> --
>> 1.7.9.5
>>