forked from Minki/linux
84d582d236
Recent discussion (http://marc.info/?l=xen-devel&m=149192184523741) established that commit72a9b18629("xen: Remove event channel notification through Xen PCI platform device") (and thus commitda72ff5bfc("partially revert "xen: Remove event channel notification through Xen PCI platform device"")) are unnecessary and, in fact, prevent HVM guests from booting on Xen releases prior to 4.0 Therefore we revert both of those commits. The summary of that discussion is below: Here is the brief summary of the current situation: Before the offending commit (72a9b18629): 1) INTx does not work because of the reset_watches path. 2) The reset_watches path is only taken if you have Xen > 4.0 3) The Linux Kernel by default will use vector inject if the hypervisor support. So even INTx does not work no body running the kernel with Xen > 4.0 would notice. Unless he explicitly disabled this feature either in the kernel or in Xen (and this can only be disabled by modifying the code, not user-supported way to do it). After the offending commit (+ partial revert): 1) INTx is no longer support for HVM (only for PV guests). 2) Any HVM guest The kernel will not boot on Xen < 4.0 which does not have vector injection support. Since the only other mode supported is INTx which. So based on this summary, I think before commit (72a9b18629) we were in much better position from a user point of view. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
35 lines
767 B
C
35 lines
767 B
C
#ifndef _ASM_X86_XEN_EVENTS_H
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#define _ASM_X86_XEN_EVENTS_H
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enum ipi_vector {
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XEN_RESCHEDULE_VECTOR,
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XEN_CALL_FUNCTION_VECTOR,
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XEN_CALL_FUNCTION_SINGLE_VECTOR,
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XEN_SPIN_UNLOCK_VECTOR,
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XEN_IRQ_WORK_VECTOR,
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XEN_NMI_VECTOR,
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XEN_NR_IPIS,
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};
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static inline int xen_irqs_disabled(struct pt_regs *regs)
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{
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return raw_irqs_disabled_flags(regs->flags);
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}
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/* No need for a barrier -- XCHG is a barrier on x86. */
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#define xchg_xen_ulong(ptr, val) xchg((ptr), (val))
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extern int xen_have_vector_callback;
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/*
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* Events delivered via platform PCI interrupts are always
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* routed to vcpu 0 and hence cannot be rebound.
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*/
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static inline bool xen_support_evtchn_rebind(void)
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{
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return (!xen_hvm_domain() || xen_have_vector_callback);
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}
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#endif /* _ASM_X86_XEN_EVENTS_H */
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