Re: [Xen-devel] [PATCH V3] x86/vm_event: block interrupt injection for sync vm_events

[Julien Grall <julien.grall@xxxxxxx>]

Hi,

On 14/01/2019 09:34, Razvan Cojocaru wrote:
> On 1/12/19 12:04 AM, Boris Ostrovsky wrote:
> > On 12/14/18 6:49 AM, Razvan Cojocaru wrote:
> > > Block interrupts (in vmx_intr_assist()) for the duration of
> > > processing a sync vm_event (similarly to the strategy
> > > currently used for single-stepping). Otherwise, attempting
> > > to emulate an instruction when requested by a vm_event
> > > reply may legitimately need to call e.g.
> > > hvm_inject_page_fault(), which then overwrites the active
> > > interrupt in the VMCS.
> > >
> > > The sync vm_event handling path on x86/VMX is (roughly):
> > > monitor_traps() -> process vm_event -> vmx_intr_assist()
> > > (possibly writing VM_ENTRY_INTR_INFO) ->
> > > hvm_vm_event_do_resume() -> hvm_emulate_one_vm_event()
> > > (possibly overwriting the VM_ENTRY_INTR_INFO value).
> > >
> > > This patch may also be helpful for the future removal
> > > of may_defer in hvm_set_cr{0,3,4} and hvm_set_msr().
> > >
> > > Signed-off-by: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>
> >
> > Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
> Thanks! So now we have three reviewed-bys, if I'm not mistaken all we need is 
> Tamas' (for the vm_event part) and Julien / Stefano's (for ARM) acks (or 
> otherwise).
> Could you please take a look?
All the Arm code modified falls under "VM EVENT, MEM ACCESS and MONITOR". So I 
don't think you need an ack from Stefano or I.
Cheers,

--
Julien Grall

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