* [PATCH] x86/vMsi-x: check whether the msixtbl_list has been initialized or not when accessing it
@ 2016-07-29 1:35 Chao Gao
2016-07-29 9:30 ` Andrew Cooper
0 siblings, 1 reply; 3+ messages in thread
From: Chao Gao @ 2016-07-29 1:35 UTC (permalink / raw)
To: xen-devel; +Cc: andrew.cooper3, jbeulich, Chao Gao
MSI-x tables' initialization had been detered in the commit
74c6dc2d0ac4dcab0c6243cdf6ed550c1532b798. If an assigned device does not support
MSI-x, the msixtbl_list won't be initialized. Howerver, both of following paths
XEN_DOMCTL_bind_pt_irq
pt_irq_create_bind
msixtbl_pt_register
and
XEN_DOMCTL_unbind_pt_irq
pt_irq_destroy_bind
msixtbl_pt_unregister
do not check this case and will cause Xen panic consequently.
Signed-off-by: Chao Gao <chao.gao@intel.com>
---
xen/arch/x86/hvm/vmsi.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/xen/arch/x86/hvm/vmsi.c b/xen/arch/x86/hvm/vmsi.c
index e418b98..e0d710b 100644
--- a/xen/arch/x86/hvm/vmsi.c
+++ b/xen/arch/x86/hvm/vmsi.c
@@ -449,7 +449,7 @@ int msixtbl_pt_register(struct domain *d, struct pirq *pirq, uint64_t gtable)
ASSERT(pcidevs_locked());
ASSERT(spin_is_locked(&d->event_lock));
- if ( !has_vlapic(d) )
+ if ( !has_vlapic(d) || !d->arch.hvm_domain.msixtbl_list.next )
return -ENODEV;
/*
@@ -519,7 +519,7 @@ void msixtbl_pt_unregister(struct domain *d, struct pirq *pirq)
ASSERT(pcidevs_locked());
ASSERT(spin_is_locked(&d->event_lock));
- if ( !has_vlapic(d) )
+ if ( !has_vlapic(d) || !d->arch.hvm_domain.msixtbl_list.next )
return;
irq_desc = pirq_spin_lock_irq_desc(pirq, NULL);
--
1.8.3.1
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^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] x86/vMsi-x: check whether the msixtbl_list has been initialized or not when accessing it
2016-07-29 1:35 [PATCH] x86/vMsi-x: check whether the msixtbl_list has been initialized or not when accessing it Chao Gao
@ 2016-07-29 9:30 ` Andrew Cooper
2016-07-30 3:00 ` gao, chao
0 siblings, 1 reply; 3+ messages in thread
From: Andrew Cooper @ 2016-07-29 9:30 UTC (permalink / raw)
To: Chao Gao, xen-devel; +Cc: jbeulich
On 29/07/16 02:35, Chao Gao wrote:
> MSI-x tables' initialization had been detered in the commit
> 74c6dc2d0ac4dcab0c6243cdf6ed550c1532b798. If an assigned device does not support
> MSI-x, the msixtbl_list won't be initialized. Howerver, both of following paths
> XEN_DOMCTL_bind_pt_irq
> pt_irq_create_bind
> msixtbl_pt_register
> and
> XEN_DOMCTL_unbind_pt_irq
> pt_irq_destroy_bind
> msixtbl_pt_unregister
> do not check this case and will cause Xen panic consequently.
>
> Signed-off-by: Chao Gao <chao.gao@intel.com>
This issue was already reported and I provided a fix in
https://xenbits.xen.org/gitweb/?p=xen.git;a=commitdiff;h=db0eee0a071e2e3e18e79d21a9b1d6724edeeeb3
However, looking at your patch, I forgot to fix the
msixtbl_pt_register() path, so your patch is still necessary.
Please rebase this patch onto the staging branch which has the
aformentioned fix in, at which point it can be accepted. Just one note.
> ---
> xen/arch/x86/hvm/vmsi.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/xen/arch/x86/hvm/vmsi.c b/xen/arch/x86/hvm/vmsi.c
> index e418b98..e0d710b 100644
> --- a/xen/arch/x86/hvm/vmsi.c
> +++ b/xen/arch/x86/hvm/vmsi.c
> @@ -449,7 +449,7 @@ int msixtbl_pt_register(struct domain *d, struct pirq *pirq, uint64_t gtable)
> ASSERT(pcidevs_locked());
> ASSERT(spin_is_locked(&d->event_lock));
>
> - if ( !has_vlapic(d) )
> + if ( !has_vlapic(d) || !d->arch.hvm_domain.msixtbl_list.next )
You can drop the vlapic() check, as it is redundant with whether msixtbl
is enabled or not.
~Andrew
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] x86/vMsi-x: check whether the msixtbl_list has been initialized or not when accessing it
2016-07-29 9:30 ` Andrew Cooper
@ 2016-07-30 3:00 ` gao, chao
0 siblings, 0 replies; 3+ messages in thread
From: gao, chao @ 2016-07-30 3:00 UTC (permalink / raw)
To: Andrew Cooper, xen-devel; +Cc: jbeulich
On Fri, Jul 29, 2016 at 10:30:07AM +0100, Andrew Cooper wrote:
>On 29/07/16 02:35, Chao Gao wrote:
>> MSI-x tables' initialization had been detered in the commit
>> 74c6dc2d0ac4dcab0c6243cdf6ed550c1532b798. If an assigned device does not support
>> MSI-x, the msixtbl_list won't be initialized. Howerver, both of following paths
>> XEN_DOMCTL_bind_pt_irq
>> pt_irq_create_bind
>> msixtbl_pt_register
>> and
>> XEN_DOMCTL_unbind_pt_irq
>> pt_irq_destroy_bind
>> msixtbl_pt_unregister
>> do not check this case and will cause Xen panic consequently.
>>
>> Signed-off-by: Chao Gao <chao.gao@intel.com>
>
>This issue was already reported and I provided a fix in
>
>https://xenbits.xen.org/gitweb/?p=xen.git;a=commitdiff;h=db0eee0a071e2e3e18e79d21a9b1d6724edeeeb3
I'm sorry for the mistake.
>However, looking at your patch, I forgot to fix the
>msixtbl_pt_register() path, so your patch is still necessary.
Actually, the msixtbl_pt_register() path never causes a panic unless wrong hypercall
paramters are given. Specially, we assign a msi capable but not msi-x capable device
to guest, but some errors(malwares, etc.) lead to calling XEN_DOMCTL_bind_pt_irq
without a clear gtable.
>Please rebase this patch onto the staging branch which has the
>aformentioned fix in, at which point it can be accepted. Just one note.
Thanks for your advice.
>> ---
>> xen/arch/x86/hvm/vmsi.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/xen/arch/x86/hvm/vmsi.c b/xen/arch/x86/hvm/vmsi.c
>> index e418b98..e0d710b 100644
>> --- a/xen/arch/x86/hvm/vmsi.c
>> +++ b/xen/arch/x86/hvm/vmsi.c
>> @@ -449,7 +449,7 @@ int msixtbl_pt_register(struct domain *d, struct pirq *pirq, uint64_t gtable)
>> ASSERT(pcidevs_locked());
>> ASSERT(spin_is_locked(&d->event_lock));
>>
>> - if ( !has_vlapic(d) )
>> + if ( !has_vlapic(d) || !d->arch.hvm_domain.msixtbl_list.next )
>
>You can drop the vlapic() check, as it is redundant with whether msixtbl
>is enabled or not.
>
>~Andrew
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2016-07-29 1:35 [PATCH] x86/vMsi-x: check whether the msixtbl_list has been initialized or not when accessing it Chao Gao
2016-07-29 9:30 ` Andrew Cooper
2016-07-30 3:00 ` gao, chao
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