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From: Jan Beulich <jbeulich@suse.com>
To: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: xen-devel@lists.xenproject.org, Wei Liu <wl@xen.org>,
	Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: [Xen-devel] [PATCH v2 4/4] x86/apic: allow enabling x2APIC mode regardless of interrupt remapping
Date: Wed, 4 Dec 2019 15:28:25 +0100	[thread overview]
Message-ID: <4b027211-359d-a669-f93b-baf860819504@suse.com> (raw)
In-Reply-To: <20191204135142.GL980@Air-de-Roger>

On 04.12.2019 14:51, Roger Pau Monné wrote:
> On Tue, Dec 03, 2019 at 04:33:09PM +0100, Jan Beulich wrote:
>> On 29.11.2019 12:28, Roger Pau Monne wrote:
>>> --- a/xen/arch/x86/apic.c
>>> +++ b/xen/arch/x86/apic.c
>>> @@ -492,7 +492,8 @@ static void __enable_x2apic(void)
>>>  
>>>  static void resume_x2apic(void)
>>>  {
>>> -    iommu_enable_x2apic();
>>> +    if ( iommu_supports_x2apic() )
>>> +        iommu_enable_x2apic();
>>
>> The hooks called by this function are __init, and at least the AMD
>> one also isn't (I think) prepared to be called more than once.
> 
> It's already called twice, there's one call to iommu_supports_x2apic
> in x2apic_bsp_setup and another one in iommu_enable_x2apic, so I think
> calling iommu_supports_x2apic multiple times is fine (or we would
> already have issues).

Ah, right - amd_iommu_prepare() bails (relatively) early when
noticing it had been called before.

Jan

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      reply	other threads:[~2019-12-04 14:28 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-29 11:28 [Xen-devel] [PATCH v2 0/4] x86: enable x2APIC mode regardless of interrupt remapping support Roger Pau Monne
2019-11-29 11:28 ` [Xen-devel] [PATCH v2 1/4] x86/ioapic: only use dest32 with x2apic and interrupt remapping enabled Roger Pau Monne
2019-12-03 15:11   ` Jan Beulich
2019-12-04 10:47     ` Roger Pau Monné
2019-11-29 11:28 ` [Xen-devel] [PATCH v2 2/4] x86/apic: force phys mode if interrupt remapping is disabled Roger Pau Monne
2019-11-29 11:38   ` Roger Pau Monné
2019-12-03 15:14     ` Jan Beulich
2019-12-04  9:17       ` Roger Pau Monné
2019-12-04  9:34         ` Jan Beulich
2019-12-04 10:50           ` Roger Pau Monné
2019-11-29 11:28 ` [Xen-devel] [PATCH v2 3/4] x86/smp: check APIC ID on AP bringup Roger Pau Monne
2019-12-03 15:23   ` Jan Beulich
2019-11-29 11:28 ` [Xen-devel] [PATCH v2 4/4] x86/apic: allow enabling x2APIC mode regardless of interrupt remapping Roger Pau Monne
2019-12-03 15:33   ` Jan Beulich
2019-12-04 13:51     ` Roger Pau Monné
2019-12-04 14:28       ` Jan Beulich [this message]

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