From: "Graf (AWS), Alexander" <graf@amazon.de>
To: "Suthikulpanit, Suravee" <Suravee.Suthikulpanit@amd.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"rkrcmar@redhat.com" <rkrcmar@redhat.com>,
"joro@8bytes.org" <joro@8bytes.org>,
"Schoenherr, Jan H." <jschoenh@amazon.de>,
"Raslan, KarimAllah" <karahmed@amazon.de>,
"Lukaszewicz, Rimas" <rimasluk@amazon.com>,
"Grimm, Jon" <Jon.Grimm@amd.com>
Subject: Re: [PATCH v2 04/15] kvm: x86: Add per-VM APICv state debugfs
Date: Wed, 28 Aug 2019 19:36:03 +0000
Message-ID: <9A47CE02-18B0-40C3-962A-D317A32F2073@amazon.de> (raw)
In-Reply-To: <1bfccb79-5ace-0dba-a201-e069f77f740a@amd.com>
> Am 28.08.2019 um 20:41 schrieb Suthikulpanit, Suravee <Suravee.Suthikulpanit@amd.com>:
>
> Alex,
>
>> On 8/27/19 3:20 AM, Alexander Graf wrote:
>>
>>
>>> On 26.08.19 21:41, Suthikulpanit, Suravee wrote:
>>> Alex,
>>>
>>>> On 8/19/2019 4:57 AM, Alexander Graf wrote:
>>>>
>>>>
>>>>> On 15.08.19 18:25, Suthikulpanit, Suravee wrote:
>>>>> Currently, there is no way to tell whether APICv is active
>>>>> on a particular VM. This often cause confusion since APICv
>>>>> can be deactivated at runtime.
>>>>>
>>>>> Introduce a debugfs entry to report APICv state of a VM.
>>>>> This creates a read-only file:
>>>>>
>>>>> /sys/kernel/debug/kvm/70860-14/apicv-state
>>>>>
>>>>> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
>>>>
>>>> Shouldn't this first and foremost be a VM ioctl so that user space
>>>> can inquire its own state?
>>>>
>>>>
>>>> Alex
>>>
>>> I introduce this mainly for debugging similar to how KVM is currently
>>> provides
>>> some per-VCPU information:
>>>
>>> /sys/kernel/debug/kvm/15957-14/vcpu0/
>>> lapic_timer_advance_ns
>>> tsc-offset
>>> tsc-scaling-ratio
>>> tsc-scaling-ratio-frac-bits
>>>
>>> I'm not sure if this needs to be VM ioctl at this point. If this
>>> information is
>>> useful for user-space tool to inquire via ioctl, we can also provide it.
>>
>> I'm mostly thinking of something like "info apic" in QEMU which to me
>> seems like the natural place for APIC information exposure to a user.
>
> I could not find QEMU "info apic". I assume you meant "info lapic",
> which provides information specific to each local APIC (i.e. per-vcpu).
Or maybe even "info kvm" :). I think you get the point.
>
>> The problem with debugfs is that it's not accessible to the user that
>> created the VM, but only root, right?
>
> Hm, you are right. I'll also look into also adding ioctl interface then.
Thanks!
Alex
Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Ralf Herbrich
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879
next prev parent reply index
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-15 16:25 [PATCH v2 00/15] kvm: x86: Support AMD SVM AVIC w/ in-kernel irqchip mode Suthikulpanit, Suravee
2019-08-15 16:25 ` [PATCH v2 01/15] kvm: x86: Modify kvm_x86_ops.get_enable_apicv() to use struct kvm parameter Suthikulpanit, Suravee
2019-08-27 7:15 ` Vitaly Kuznetsov
2019-08-15 16:25 ` [PATCH v2 02/15] kvm: x86: Introduce KVM APICv state Suthikulpanit, Suravee
2019-08-19 9:49 ` Alexander Graf
2019-08-26 19:06 ` Suthikulpanit, Suravee
2019-08-15 16:25 ` [PATCH v2 03/15] kvm: Add arch-specific per-VM debugfs support Suthikulpanit, Suravee
2019-08-15 16:25 ` [PATCH v2 04/15] kvm: x86: Add per-VM APICv state debugfs Suthikulpanit, Suravee
2019-08-19 9:57 ` Alexander Graf
2019-08-26 19:41 ` Suthikulpanit, Suravee
2019-08-27 8:20 ` Alexander Graf
2019-08-28 18:39 ` Suthikulpanit, Suravee
2019-08-28 19:36 ` Graf (AWS), Alexander [this message]
2019-08-15 16:25 ` [PATCH v2 05/15] kvm: lapic: Introduce APICv update helper function Suthikulpanit, Suravee
2019-08-27 7:22 ` Vitaly Kuznetsov
2019-08-15 16:25 ` [PATCH v2 06/15] kvm: x86: Add support for activate/de-activate APICv at runtime Suthikulpanit, Suravee
2019-08-27 7:29 ` Vitaly Kuznetsov
2019-08-27 8:05 ` Alexander Graf
2019-08-15 16:25 ` [PATCH v2 07/15] kvm: x86: svm: Add support to activate/deactivate posted interrupts Suthikulpanit, Suravee
2019-08-15 16:25 ` [PATCH v2 08/15] svm: Add support for setup/destroy virutal APIC backing page for AVIC Suthikulpanit, Suravee
2019-08-15 16:25 ` [PATCH v2 09/15] svm: Add support for activate/deactivate AVIC at runtime Suthikulpanit, Suravee
2019-08-19 10:28 ` Alexander Graf
2019-08-15 16:25 ` [PATCH v2 10/15] kvm: x86: hyperv: Use APICv deactivate request interface Suthikulpanit, Suravee
2019-08-19 10:31 ` Alexander Graf
2019-08-15 16:25 ` [PATCH v2 11/15] svm: Temporary deactivate AVIC during ExtINT handling Suthikulpanit, Suravee
2019-08-19 10:35 ` Alexander Graf
2019-08-28 15:17 ` Suthikulpanit, Suravee
2019-08-28 19:37 ` Graf (AWS), Alexander
2019-09-10 15:46 ` Suthikulpanit, Suravee
2019-08-15 16:25 ` [PATCH v2 12/15] kvm: i8254: Check LAPIC EOI pending when injecting irq on SVM AVIC Suthikulpanit, Suravee
2019-08-19 10:42 ` Alexander Graf
2019-08-26 20:46 ` Suthikulpanit, Suravee
2019-08-27 9:10 ` Alexander Graf
2019-09-13 14:50 ` Suthikulpanit, Suravee
2019-08-15 16:25 ` [PATCH v2 13/15] kvm: lapic: Clean up APIC predefined macros Suthikulpanit, Suravee
2019-08-15 16:25 ` [PATCH v2 14/15] kvm: ioapic: Delay update IOAPIC EOI for RTC Suthikulpanit, Suravee
2019-08-19 11:00 ` Alexander Graf
2019-09-04 2:06 ` Suthikulpanit, Suravee
2019-08-15 16:25 ` [PATCH v2 15/15] svm: Allow AVIC with in-kernel irqchip mode Suthikulpanit, Suravee
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