RE: [v3 00/26] Add VT-d Posted-Interrupts support
From: Wu, Feng
Date: Tue Jan 27 2015 - 23:45:14 EST
> -----Original Message-----
> From: Alex Williamson [mailto:alex.williamson@xxxxxxxxxx]
> Sent: Wednesday, January 28, 2015 11:44 AM
> To: Wu, Feng
> Cc: tglx@xxxxxxxxxxxxx; mingo@xxxxxxxxxx; hpa@xxxxxxxxx; x86@xxxxxxxxxx;
> gleb@xxxxxxxxxx; pbonzini@xxxxxxxxxx; dwmw2@xxxxxxxxxxxxx;
> joro@xxxxxxxxxx; jiang.liu@xxxxxxxxxxxxxxx; eric.auger@xxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx;
> kvm@xxxxxxxxxxxxxxx
> Subject: Re: [v3 00/26] Add VT-d Posted-Interrupts support
>
> On Wed, 2015-01-28 at 03:01 +0000, Wu, Feng wrote:
> >
> > > -----Original Message-----
> > > From: Wu, Feng
> > > Sent: Wednesday, January 21, 2015 10:26 AM
> > > To: tglx@xxxxxxxxxxxxx; mingo@xxxxxxxxxx; hpa@xxxxxxxxx;
> x86@xxxxxxxxxx;
> > > gleb@xxxxxxxxxx; pbonzini@xxxxxxxxxx; dwmw2@xxxxxxxxxxxxx;
> > > joro@xxxxxxxxxx; alex.williamson@xxxxxxxxxx; jiang.liu@xxxxxxxxxxxxxxx
> > > Cc: eric.auger@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> > > iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; Wu, Feng
> > > Subject: RE: [v3 00/26] Add VT-d Posted-Interrupts support
> > >
> > >
> > > > -----Original Message-----
> > > > From: Wu, Feng
> > > > Sent: Friday, December 12, 2014 11:15 PM
> > > > To: tglx@xxxxxxxxxxxxx; mingo@xxxxxxxxxx; hpa@xxxxxxxxx;
> > > x86@xxxxxxxxxx;
> > > > gleb@xxxxxxxxxx; pbonzini@xxxxxxxxxx; dwmw2@xxxxxxxxxxxxx;
> > > > joro@xxxxxxxxxx; alex.williamson@xxxxxxxxxx; jiang.liu@xxxxxxxxxxxxxxx
> > > > Cc: eric.auger@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> > > > iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; Wu, Feng
> > > > Subject: [v3 00/26] Add VT-d Posted-Interrupts support
> > > >
> > > > VT-d Posted-Interrupts is an enhancement to CPU side Posted-Interrupt.
> > > > With VT-d Posted-Interrupts enabled, external interrupts from
> > > > direct-assigned devices can be delivered to guests without VMM
> > > > intervention when guest is running in non-root mode.
> > > >
> > > > You can find the VT-d Posted-Interrtups Spec. in the following URL:
> > > >
> > >
> http://www.intel.com/content/www/us/en/intelligent-systems/intel-technolog
> > > > y/vt-directed-io-spec.html
> > > >
> > > > v1->v2:
> > > > * Use VFIO framework to enable this feature, the VFIO part of this series is
> > > > base on Eric's patch "[PATCH v3 0/8] KVM-VFIO IRQ forward control"
> > > > * Rebase this patchset on
> > > > git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git,
> > > > then revise some irq logic based on the new hierarchy irqdomain
> patches
> > > > provided
> > > > by Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
> > > >
> > > > v2->v3:
> > > > * Adjust the Posted-interrupts Descriptor updating logic when vCPU is
> > > > preempted or blocked.
> > > > * KVM_DEV_VFIO_DEVICE_POSTING_IRQ -->
> > > > KVM_DEV_VFIO_DEVICE_POST_IRQ
> > > > * __KVM_HAVE_ARCH_KVM_VFIO_POSTING -->
> > > > __KVM_HAVE_ARCH_KVM_VFIO_POST
> > > > * Add KVM_DEV_VFIO_DEVICE_UNPOST_IRQ attribute for VFIO irq, which
> > > > can be used to change back to remapping mode.
> > > > * Fix typo
> > > >
> > > > This patch series is made of the following groups:
> > > > 1-6: Some preparation changes in iommu and irq component, this is based
> on
> > > > the
> > > > new hierarchy irqdomain logic.
> > > > 7-9, 26: IOMMU changes for VT-d Posted-Interrupts, such as, feature
> > > > detection,
> > > > command line parameter.
> > > > 10-17, 22-25: Changes related to KVM itself.
> > > > 18-20: Changes in VFIO component, this part was previously sent out as
> > > > "[RFC PATCH v2 0/2] kvm-vfio: implement the vfio skeleton for VT-d
> > > > Posted-Interrupts"
> > > > 21: x86 irq related changes
> > > >
> > > > Feng Wu (26):
> > > > genirq: Introduce irq_set_vcpu_affinity() to target an interrupt to a
> > > > VCPU
> > > > iommu: Add new member capability to struct irq_remap_ops
> > > > iommu, x86: Define new irte structure for VT-d Posted-Interrupts
> > > > iommu, x86: Implement irq_set_vcpu_affinity for intel_ir_chip
> > > > x86, irq: Implement irq_set_vcpu_affinity for pci_msi_ir_controller
> > > > iommu, x86: No need to migrating irq for VT-d Posted-Interrupts
> > > > iommu, x86: Add cap_pi_support() to detect VT-d PI capability
> > > > iommu, x86: Add intel_irq_remapping_capability() for Intel
> > > > iommu, x86: define irq_remapping_cap()
> > > > KVM: change struct pi_desc for VT-d Posted-Interrupts
> > > > KVM: Add some helper functions for Posted-Interrupts
> > > > KVM: Initialize VT-d Posted-Interrupts Descriptor
> > > > KVM: Define a new interface kvm_find_dest_vcpu() for VT-d PI
> > > > KVM: Get Posted-Interrupts descriptor address from struct kvm_vcpu
> > > > KVM: add interfaces to control PI outside vmx
> > > > KVM: Make struct kvm_irq_routing_table accessible
> > > > KVM: make kvm_set_msi_irq() public
> > > > KVM: kvm-vfio: User API for VT-d Posted-Interrupts
> > > > KVM: kvm-vfio: implement the VFIO skeleton for VT-d Posted-Interrupts
> > > > KVM: x86: kvm-vfio: VT-d posted-interrupts setup
> > > > x86, irq: Define a global vector for VT-d Posted-Interrupts
> > > > KVM: Define a wakeup worker thread for vCPU
> > > > KVM: Update Posted-Interrupts Descriptor when vCPU is preempted
> > > > KVM: Update Posted-Interrupts Descriptor when vCPU is blocked
> > > > KVM: Suppress posted-interrupt when 'SN' is set
> > > > iommu/vt-d: Add a command line parameter for VT-d posted-interrupts
> > > >
> > > > Documentation/kernel-parameters.txt | 1 +
> > > > Documentation/virtual/kvm/devices/vfio.txt | 9 ++
> > > > arch/x86/include/asm/entry_arch.h | 2 +
> > > > arch/x86/include/asm/hardirq.h | 1 +
> > > > arch/x86/include/asm/hw_irq.h | 2 +
> > > > arch/x86/include/asm/irq_remapping.h | 11 ++
> > > > arch/x86/include/asm/irq_vectors.h | 1 +
> > > > arch/x86/include/asm/kvm_host.h | 12 ++
> > > > arch/x86/kernel/apic/msi.c | 1 +
> > > > arch/x86/kernel/entry_64.S | 2 +
> > > > arch/x86/kernel/irq.c | 27 ++++
> > > > arch/x86/kernel/irqinit.c | 2 +
> > > > arch/x86/kvm/Makefile | 2 +-
> > > > arch/x86/kvm/kvm_vfio_x86.c | 77 +++++++++
> > > > arch/x86/kvm/vmx.c | 244
> > > > ++++++++++++++++++++++++++++-
> > > > arch/x86/kvm/x86.c | 22 ++-
> > > > drivers/iommu/intel_irq_remapping.c | 68 +++++++-
> > > > drivers/iommu/irq_remapping.c | 24 ++-
> > > > drivers/iommu/irq_remapping.h | 8 +
> > > > include/linux/dmar.h | 32 ++++
> > > > include/linux/intel-iommu.h | 1 +
> > > > include/linux/irq.h | 7 +
> > > > include/linux/kvm_host.h | 46 ++++++
> > > > include/uapi/linux/kvm.h | 11 ++
> > > > kernel/irq/chip.c | 14 ++
> > > > kernel/irq/manage.c | 20 +++
> > > > virt/kvm/irq_comm.c | 43 ++++-
> > > > virt/kvm/irqchip.c | 11 --
> > > > virt/kvm/kvm_main.c | 15 ++
> > > > virt/kvm/vfio.c | 107 +++++++++++++
> > > > 30 files changed, 795 insertions(+), 28 deletions(-)
> > > > create mode 100644 arch/x86/kvm/kvm_vfio_x86.c
> > > >
> > >
> > > Hi Paolo, Alex, and other maintainers,
> > >
> > > Since this series contain multiple subsystems, IOMMU, irq, x86, VFIO, KVM,
> etc.
> > > I am wondering how you guys handled this case before? If all the patches are
> > > reviewed and acked by the associated maintainer, are you only merge the
> > > patches
> > > related to your own subsystem to your tree? However, you may also need
> get
> > > other
> > > patches to make the build successful, so I am a little curious about how you
> guys
> > > handle this? Thanks a lot!
> >
> > Can anyone share some experiences about this?
>
> Generally you need to split the patches into logical changes per
> subsystem and submit them separately through the mailing list and
> maintainer. This helps to make sure the changes make sense and stand on
> their own and aren't simply a hack to reach the end goal. Submit what
> you can in parallel, but expect that if you send patches dependent on
> other, unmerged series, they will get ignored and will need to be resent
> when the dependencies are resolved in -next. Thanks,
>
> Alex
Thanks a lot for your response, Alex! I am still waiting for comments for
the generic IRQ and IOMMU parts, after I got the comments, I will consider
your advice in the next post. Thank you!
Thanks,
Feng