Re: [Xen-devel] [RFC Patch v2 45/45] x86/hvm: Always set pending event injection when loading VMC[BS] state.

[Aravind Gopalakrishnan <aravind.gopalakrishnan@xxxxxxx>]

On 8/26/2014 7:46 PM, Wen Congyang wrote:
> At 08/27/2014 12:02 AM, Jan Beulich Write:
> > > > > On 08.08.14 at 09:01, <wency@xxxxxxxxxxxxxx> wrote:
> > > In colo mode, secondary vm is running, so VM_ENTRY_INTR_INFO may
> > > valid before restoring vmcs. If there is no pending event after
> > > restoring vm, we should clear it.
> > >
> > > Signed-off-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
> > >
> > > Also clear pending software exceptions.
> > > Copy the fix to SVM as well.
> > >
> > > Signed-off-by: Tim Deegan <tim@xxxxxxx>
> > I only now realized that it's no surprise we're not getting acks from
> > the VMX maintainers on this - the majority of them wasn't Cc-ed.
> > Now done, but please take care to do so yourself in the future.
> >
> > As to the SVM maintainers - Ping (I Cc-ed you on an earlier reply)?
> Thanks for doing this.
> I have repost it in the bugfix patchset, and cc vmx and svm maintainers
Hi,
Apologies for the delay.

As for the svm changes, the patch seems fairly straightforward and harmless.
However, I am not familiar with 'colo mode', so I'm not sure I 
understand the problem..
Is this a 'fix' we need so that we don't duplicate a pending software 
interrupt on the secondary VM?
Is there a way to test this?

Thanks,
-Aravind.

> > > ---
> > >   xen/arch/x86/hvm/svm/svm.c | 16 +++++++++-------
> > >   xen/arch/x86/hvm/vmx/vmx.c | 25 ++++++++++++-------------
> > >   2 files changed, 21 insertions(+), 20 deletions(-)
> > >
> > > diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
> > > index 71b8a6a..f7a0cb8 100644
> > > --- a/xen/arch/x86/hvm/svm/svm.c
> > > +++ b/xen/arch/x86/hvm/svm/svm.c
> > > @@ -321,16 +321,18 @@ static int svm_vmcb_restore(struct vcpu *v, struct
> > > hvm_hw_cpu *c)
> > >           vmcb_set_h_cr3(vmcb, pagetable_get_paddr(p2m_get_pagetable(p2m)));
> > >       }
> > >   
> > > -    if ( c->pending_valid )
> > > +    if ( c->pending_valid
> > > +         && hvm_event_needs_reinjection(c->pending_type, c->pending_vector) )
> > >       {
> > >           gdprintk(XENLOG_INFO, "Re-injecting %#"PRIx32", %#"PRIx32"\n",
> > >                    c->pending_event, c->error_code);
> > > -
> > > -        if ( hvm_event_needs_reinjection(c->pending_type, c->pending_vector) )
> > > -        {
> > > -            vmcb->eventinj.bytes = c->pending_event;
> > > -            vmcb->eventinj.fields.errorcode = c->error_code;
> > > -        }
> > > +        vmcb->eventinj.bytes = c->pending_event;
> > > +        vmcb->eventinj.fields.errorcode = c->error_code;
> > > +    }
> > > +    else
> > > +    {
> > > +        vmcb->eventinj.bytes = 0;
> > > +        vmcb->eventinj.fields.errorcode = 0;
> > >       }
> > >   
> > >       vmcb->cleanbits.bytes = 0;
> > > diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
> > > index fb65c7d..5f143c0 100644
> > > --- a/xen/arch/x86/hvm/vmx/vmx.c
> > > +++ b/xen/arch/x86/hvm/vmx/vmx.c
> > > @@ -509,23 +509,22 @@ static int vmx_vmcs_restore(struct vcpu *v, struct
> > > hvm_hw_cpu *c)
> > >   
> > >       __vmwrite(GUEST_DR7, c->dr7);
> > >   
> > > -    vmx_vmcs_exit(v);
> > > -
> > > -    paging_update_paging_modes(v);
> > > -
> > > -    if ( c->pending_valid )
> > > +    if ( c->pending_valid
> > > +         && hvm_event_needs_reinjection(c->pending_type, c->pending_vector) )
> > >       {
> > >           gdprintk(XENLOG_INFO, "Re-injecting %#"PRIx32", %#"PRIx32"\n",
> > >                    c->pending_event, c->error_code);
> > > -
> > > -        if ( hvm_event_needs_reinjection(c->pending_type, c->pending_vector) )
> > > -        {
> > > -            vmx_vmcs_enter(v);
> > > -            __vmwrite(VM_ENTRY_INTR_INFO, c->pending_event);
> > > -            __vmwrite(VM_ENTRY_EXCEPTION_ERROR_CODE, c->error_code);
> > > -            vmx_vmcs_exit(v);
> > > -        }
> > > +        __vmwrite(VM_ENTRY_INTR_INFO, c->pending_event);
> > > +        __vmwrite(VM_ENTRY_EXCEPTION_ERROR_CODE, c->error_code);
> > >       }
> > > +    else
> > > +    {
> > > +        __vmwrite(VM_ENTRY_INTR_INFO, 0);
> > > +        __vmwrite(VM_ENTRY_EXCEPTION_ERROR_CODE, 0);
> > > +    }
> > > +    vmx_vmcs_exit(v);
> > > +
> > > +    paging_update_paging_modes(v);
> > >   
> > >       return 0;
> > >   }
> > > --
> > > 1.9.3
> > >
> > >
> > > _______________________________________________
> > > Xen-devel mailing list
> > > Xen-devel@xxxxxxxxxxxxx
> > > http://lists.xen.org/xen-devel
> >
> > .

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