From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: david.vrabel@citrix.com, konrad.wilk@oracle.com,
jun.nakajima@intel.com, linux-kernel@vger.kernel.org,
xen-devel@lists.xen.org
Subject: Re: [PATCH v3 1/2] xen/pci: Defer initialization of MSI ops on HVM guests until after x2APIC has been set up
Date: Tue, 25 Nov 2014 10:11:39 -0500 [thread overview]
Message-ID: <54749C2B.4090303@oracle.com> (raw)
In-Reply-To: <alpine.DEB.2.02.1411251205220.2675@kaball.uk.xensource.com>
On 11/25/2014 07:06 AM, Stefano Stabellini wrote:
> On Mon, 24 Nov 2014, Boris Ostrovsky wrote:
>> If the hardware supports APIC virtualization we may decide not to use pirqs
>> and instead use APIC/x2APIC directly, meaning that we don't want to set
>> x86_msi.setup_msi_irqs and x86_msi.teardown_msi_irq to Xen-specific routines.
>> However, x2APIC is not set up by the time pci_xen_hvm_init() is called so we
>> need to postpone setting these ops until later, when we know which APIC mode
>> is used.
>>
>> (Note that currently x2APIC is never initialized on HVM guests. This may
>> change in the future)
> I take that this is safe because no MSIs can be received at this point
> (apic_post_init), right?
Yes. At the time apic_post_init() is called PCI has not been probed yet.
-boris
next prev parent reply other threads:[~2014-11-25 15:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-24 23:06 [PATCH v3 0/2] xen/pci: Use APIC for MSIs when APIC virtualization is supported Boris Ostrovsky
2014-11-24 23:06 ` [PATCH v3 1/2] xen/pci: Defer initialization of MSI ops on HVM guests until after x2APIC has been set up Boris Ostrovsky
2014-11-25 12:06 ` Stefano Stabellini
2014-11-25 15:11 ` Boris Ostrovsky [this message]
2014-11-25 15:12 ` Stefano Stabellini
2014-11-24 23:06 ` [PATCH v3 2/2] xen/pci: Use APIC directly when APIC virtualization is supported by hardware Boris Ostrovsky
2014-11-25 12:05 ` Stefano Stabellini
2014-11-25 16:17 ` [PATCH v3 0/2] xen/pci: Use APIC for MSIs when APIC virtualization is supported Konrad Rzeszutek Wilk
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