Re: [Xen-devel] [PATCH v2] x86/passthrough: fix migration of MSI when using posted interrupts

[Joe Jin <joe.jin@xxxxxxxxxx>]

On 10/30/19 10:23 AM, Roger Pau Monné wrote:
> On Wed, Oct 30, 2019 at 09:38:16AM -0700, Joe Jin wrote:
>> On 10/30/19 1:24 AM, Roger Pau Monné wrote:
>>> Can you try to add the following debug patch on top of the existing
>>> one and report the output that you get on the Xen console?
>>
>> Applied debug patch and run the test again, not of any log printed,
>> attached Xen log on serial console, seems pi_update_irte() not been
>> called for iommu_intpost was false.
> 
> I have to admit I'm lost at this point. Does it mean the original
> issue had nothing to do with posted interrupts?

Looks when inject irq by vlapic_set_irq(), it checked by
hvm_funcs.deliver_posted_intr rather than iommu_intpost:

 176     if ( hvm_funcs.deliver_posted_intr )
 177         hvm_funcs.deliver_posted_intr(target, vec);

And deliver_posted_intr() would be there, when vmx enabled:

(XEN) HVM: VMX enabled
(XEN) HVM: Hardware Assisted Paging (HAP) detected
(XEN) HVM: HAP page sizes: 4kB, 2MB, 1GB

So original issue still used posted interrupts?

> 
> Where you booting using iommu=intpost in your previous tests? Note
> that posted interrupts is not enabled by default according to the
> command line documentation.
> 

No, from xen command line you can see I only had iommu=1 for xen.

> Can you confirm whether you also see weird behavior without using
> posted interrupts, and can you turn posted interrupts on and give the
> patch a try?

I disabled apicv, looks posted interrupts been disables as well, then
I could not reproduced it anymore:

(XEN) Command line: placeholder dom0_mem=max:3456M allowsuperpage 
dom0_vcpus_pin=numa dom0_max_vcpus=4 crashkernel=512M@1024M 
iommu=verbose,debug,force,intremap,intpost hvm_debug=832 guest_loglvl=all 
com1=115200,8n1 console=com1 conring_size=1m console_to_ring apicv=0
...
(XEN) Initing memory sharing.
(XEN) Intel VT-d iommu 0 supported page sizes: 4kB, 2MB, 1GB.
(XEN) Intel VT-d iommu 1 supported page sizes: 4kB, 2MB, 1GB.
(XEN) Intel VT-d Snoop Control enabled.
(XEN) Intel VT-d Dom0 DMA Passthrough not enabled.
(XEN) Intel VT-d Queued Invalidation enabled.
(XEN) Intel VT-d Interrupt Remapping enabled.
(XEN) Intel VT-d Posted Interrupt not enabled.
(XEN) Intel VT-d Shared EPT tables enabled.
...
(XEN) VMX: Supported advanced features:
(XEN)  - APIC MMIO access virtualisation
(XEN)  - APIC TPR shadow
(XEN)  - Extended Page Tables (EPT)
(XEN)  - Virtual-Processor Identifiers (VPID)
(XEN)  - Virtual NMI
(XEN)  - MSR direct-access bitmap
(XEN)  - Unrestricted Guest
(XEN)  - VMCS shadowing
(XEN)  - VM Functions
(XEN) HVM: ASIDs enabled.
(XEN) HVM: VMX enabled

Thanks,
Joe


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