From: Roman Kagan <rkagan@virtuozzo.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"K. Y. Srinivasan" <kys@microsoft.com>,
"Haiyang Zhang" <haiyangz@microsoft.com>,
"Stephen Hemminger" <sthemmin@microsoft.com>,
"x86@kernel.org" <x86@kernel.org>,
"Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>
Subject: Re: [PATCH v2 3/4] x86/kvm/hyper-v: direct mode for synthetic timers
Date: Mon, 10 Dec 2018 13:21:39 +0000 [thread overview]
Message-ID: <20181210132134.GA5888@rkaganb.sw.ru> (raw)
In-Reply-To: <87va41czk5.fsf@vitty.brq.redhat.com>
On Mon, Dec 10, 2018 at 01:54:18PM +0100, Vitaly Kuznetsov wrote:
> Roman Kagan <rkagan@virtuozzo.com> writes:
> > Just noticed that the patch seems to assume that "direct" timers are
> > allowed to use any vectors including 0-15. I guess this is incorrect,
> > and instead stimer_set_config should error out on direct mode with a
> > vector less than HV_SYNIC_FIRST_VALID_VECTOR.
>
> The spec is really vague about this and I'm not sure that this has
> anything to do with HV_SYNIC_FIRST_VALID_VECTOR (as these are actually
> not "synic" vectors, I *think* that SynIC doesn't even need to be
> enabled to make them work).
>
> I checked and Hyper-V 2016 uses vector '0xff', not sure if it proves
> your point :-)
>
> Do you envision any issues in KVM if we keep allowing vectors <
> HV_SYNIC_FIRST_VALID_VECTOR?
It's actually lapic that treats vectors 0..15 as illegal. Nothing
Hyper-V specific here.
Roman.
next prev parent reply other threads:[~2018-12-10 13:21 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-26 15:47 [PATCH v2 0/4] x86/kvm/hyper-v: Implement Direct Mode for synthetic timers Vitaly Kuznetsov
2018-11-26 15:47 ` [PATCH v2 1/4] x86/hyper-v: move synic/stimer control structures definitions to hyperv-tlfs.h Vitaly Kuznetsov
2018-11-26 17:00 ` Michael Kelley
2018-11-26 20:04 ` Roman Kagan
2018-11-27 13:10 ` Vitaly Kuznetsov
2018-11-27 15:52 ` Michael Kelley
2018-11-27 16:32 ` Vitaly Kuznetsov
2018-11-27 18:48 ` Roman Kagan
2018-11-28 1:49 ` Nadav Amit
2018-11-28 10:37 ` Vitaly Kuznetsov
2018-11-28 13:07 ` Thomas Gleixner
2018-11-28 17:55 ` Nadav Amit
2018-11-29 11:36 ` Vitaly Kuznetsov
2018-11-29 19:22 ` Thomas Gleixner
2018-11-29 7:52 ` Roman Kagan
2018-11-28 8:40 ` Paolo Bonzini
2018-11-26 15:47 ` [PATCH v2 2/4] x86/kvm/hyper-v: use stimer config definition from hyperv-tlfs.h Vitaly Kuznetsov
2018-11-26 15:47 ` [PATCH v2 3/4] x86/kvm/hyper-v: direct mode for synthetic timers Vitaly Kuznetsov
2018-11-26 16:44 ` Paolo Bonzini
2018-11-26 17:14 ` Vitaly Kuznetsov
2018-11-27 8:37 ` Roman Kagan
2018-11-27 13:54 ` Paolo Bonzini
2018-11-27 19:05 ` Roman Kagan
2018-11-28 8:43 ` Paolo Bonzini
2018-11-27 8:21 ` Roman Kagan
2018-12-03 17:12 ` Roman Kagan
2018-12-04 12:36 ` Vitaly Kuznetsov
2018-12-10 12:06 ` Roman Kagan
2018-12-10 12:54 ` Vitaly Kuznetsov
2018-12-10 13:21 ` Roman Kagan [this message]
2018-12-10 14:53 ` Vitaly Kuznetsov
2018-11-26 15:47 ` [PATCH v2 4/4] x86/kvm/hyper-v: avoid open-coding stimer_mark_pending() in kvm_hv_notify_acked_sint() Vitaly Kuznetsov
2018-11-26 16:45 ` Paolo Bonzini
2018-11-27 8:49 ` Roman Kagan
2018-11-26 16:45 ` [PATCH v2 0/4] x86/kvm/hyper-v: Implement Direct Mode for synthetic timers Paolo Bonzini
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