Re: [Xen-devel] [PATCH v2 00/30] PVHv2 Dom0

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

On Tue, Sep 27, 2016 at 05:56:55PM +0200, Roger Pau Monne wrote:
> Hello,
> 
> This is the first "complete" PVHv2 implementation in the sense that
> it has feature parity with classic PVH Dom0. It is still very experimental,
> but I've managed to boot it on all Intel boxes I've tried (OK, only 3 so far).
> I've also tried on an AMD box, but sadly the ACPI tables there didn't contain
> any RMRR regions and the IOMMU started spitting a bunch of page faults caused
> by devices trying to access memory regions marked as reserved in the e820.
> 
> Here is the list of most relevant changes compared to classic PVH or PV:
> 
>  - An emulated local APIC (for each vCPU) and IO APIC is provided to Dom0.
>  - The MADT has been replaced in order to reflect the real topology seen by
>    the guest. This needs a little bit more of work so that the new MADT is
>    not placed over the old one.
>  - BARs of PCI devices are automatically mapped by Xen into Dom0 memory space.
>    Currently there's no support for changing the position of the BARs, and Xen
>    will just crash the domain if this is attempted.
>  - Interrupts from physical devices are configured and routed using native
>    mechanism, PIRQs are not available to this PVH Dom0 implementation at all.
>    Xen will automatically detect the features of the physical devices 
> available
>    to Dom0, and will setup traps/handlers in order to intercept all relevant
>    configuration accesses.
>  - Access to PCIe regions is also trapped by Xen, so configuration can be done
>    using the IO ports or the memory mapped configuration areas, as supported
>    by each device.
>  - Some ACPI tables are zapped (it's signature is inverted) to prevent Dom0
>    from poking at them, those are: HPET, SLIT, SRAT, MPST and PMTT.
> 
> I know this series is quite big, but I think some of the initial changes can
> go in as bugfixes, which would help me reduce the size.
> 

I've forgotten to push this to my personal git repo, the series can be found 
at:

git://xenbits.xen.org/people/royger/xen.git dom0_hvm_v2

(with the recent comments from this morning addressed)

I've also forgot to mention that on one Intel box, that's a two socket 
machine with Xeon E5520 and a 5520/5500 chipset with two IO APICs I need to 
forcefully set the IO APIC ack mode to 'old', or else legacy PCI interrupts 
get stuck with irr=1. And even when doing that, after some uptime Dom0 
starts losing MSI and MSI-X interrupts. I haven't been able to reproduce 
this on any other box.

Roger.

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