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Re: [Qemu-devel] [Xen-devel] [RFC PATCH 0/4] Qemu: Add Xen vIOMMU suppor
Re: [Qemu-devel] [Xen-devel] [RFC PATCH 0/4] Qemu: Add Xen vIOMMU support
Mon, 20 Mar 2017 15:35:55 +0100
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On 20/03/2017 15:17, Roger Pau Monné wrote:
>>> Hi Paolo:
>>> Thanks for review. For Xen side, we won't reuse Intel IOMMU device model
>>> in Qemu and create counterpart in Xen hypervisor. The reasons are
>>> 1) Avoid round trips between Qemu and Xen hypervisor
>>> 2) Ease of integration with the rest part of the hypervisor(vIOAPIC,
>>> vMSI and so on).
>> Fair enough, though I'd be worried about increasing the attack surface
>> of the hypervisor. For KVM, for example, IOMMU emulation requires using
>> the "split irqchip" feature to move the PIC and IOAPIC out of the kernel
>> and back to QEMU.
> Yes, that's right, we are increasing the surface of attack. But Xen also needs
> it in order to support APIC IDs > 255 on PVH guests (that have a local APIC
> no QEMU).
Not necessarily, you only need x2APIC support for that in the local APIC
emulation. The MSI hypercalls (similar to KVM's MSI ioctls) can be
extended to accept x2APIC VCPU ids.
- Re: [Qemu-devel] [RFC PATCH 1/4] I440: Allow adding sysbus devices with -device on I440, (continued)
- [Qemu-devel] [RFC PATCH 3/4] xen-pt: bind/unbind interrupt remapping format MSI, Lan Tianyu, 2017/03/17
- [Qemu-devel] [RFC PATCH 2/4] Xen: add a dummy vIOMMU to create/destroy vIOMMU in Xen, Lan Tianyu, 2017/03/17
- [Qemu-devel] [RFC PATCH 4/4] msi: taking interrupt format into consideration during judging a pirq is binded with a event channel, Lan Tianyu, 2017/03/17
- Re: [Qemu-devel] [RFC PATCH 0/4] Qemu: Add Xen vIOMMU support, no-reply, 2017/03/17
- Re: [Qemu-devel] [RFC PATCH 0/4] Qemu: Add Xen vIOMMU support, Paolo Bonzini, 2017/03/17