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[Xen-devel] [PATCH 0/7] PV on HVM: receive interrupts as xen events

To: <linux-kernel@xxxxxxxxxxxxxxx>
Subject: [Xen-devel] [PATCH 0/7] PV on HVM: receive interrupts as xen events
From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Date: Mon, 30 Aug 2010 12:20:17 +0100
Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx, Stefano Stabellini <Stefano.Stabellini@xxxxxxxxxxxxx>, Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
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Hi all,
this patch series introduces some performance improvements for xen PV on
HVM guests: interacting with the emulated APIC is slow because it causes
traps in the hypervisor while receiving xen events using the vector callback
mechanism allow us to skip all that. For this reason we remap interrupts
and MSIs into xen pirqs so that from that point on we can receive them
as xen events instead.
This series is based on Konrad's pcifront series (not upstream yet):


and requires a patch to xen and a patch to qemu-xen (just sent to

The list of patches with diffstat follows:

Jeremy Fitzhardinge (2):
 xen: add xen hvm acpi_register_gsi variant
 acpi: use indirect call to register gsi in different modes

Stefano Stabellini (5):
 xen: xen: map MSIs into pirqs
 xen: support GSI -> pirq remapping in PV on HVM guests
 xen: implement xen_hvm_register_pirq
 xen: get the maximum number of pirqs from xen
 xen: support pirq != irq

 arch/x86/include/asm/acpi.h      |    3 +
 arch/x86/include/asm/xen/pci.h   |   10 +++
 arch/x86/kernel/acpi/boot.c      |   60 ++++++++++++++------
 arch/x86/pci/xen.c               |  114 ++++++++++++++++++++++++++++++++++++++
 drivers/pci/xen-pcifront.c       |    2 +-
 drivers/xen/events.c             |  106 +++++++++++++++++++++++++++++++----
 include/xen/events.h             |    3 +
 include/xen/interface/features.h |    3 +
 include/xen/interface/physdev.h  |   36 ++++++++++++
 9 files changed, 308 insertions(+), 29 deletions(-)

A git tree with this series and Konrad's pcifront series on top of Linux
2.6.36-rc1 is available here:



Stefano Stabellini

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