[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH] Qemu/Xen: Fix early freeing MSIX MMIO memory re
From: |
Stefano Stabellini |
Subject: |
Re: [Qemu-devel] [PATCH] Qemu/Xen: Fix early freeing MSIX MMIO memory region |
Date: |
Mon, 12 Oct 2015 12:09:49 +0100 |
User-agent: |
Alpine 2.02 (DEB 1266 2009-07-14) |
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?
> 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
>