From: Jan Kiszka <jan.kiszka@web.de>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Avi Kivity <avi@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
kvm@vger.kernel.org, qemu-devel <qemu-devel@nongnu.org>,
Anthony Liguori <aliguori@us.ibm.com>,
Gleb Natapov <gleb@redhat.com>
Subject: Re: [PATCH 3/6] kvmvapic: Introduce TPR access optimization for Windows guests
Date: Thu, 09 Feb 2012 19:01:40 +0100 [thread overview]
Message-ID: <4F340A04.5080303@web.de> (raw)
In-Reply-To: <4F340066.9070108@redhat.com>
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On 2012-02-09 18:20, Paolo Bonzini wrote:
> On 02/09/2012 05:32 PM, Jan Kiszka wrote:
>> > I mean just check kpcr.self.
>>
>> Yes, clear, but that means that Windows must have initialized FS.base to
>> point to the KPCR also in UP mode. Is that really the case? E.g. when
>> ACPI is off?! I wonder if that explains the reported bug of qemu-kvm
>> with -no-acpi and in-kernel irqchip...
>
> Yes, it does. It's used by some fast-path kernel APIs, and indeed the
> canonical way to find the KPCR base from ring 0 is to look at FS:[1Ch].
Yep, can confirm this so far. I briefly tested a non-ACPI installation,
and it both works without problems on qemu-kvm and shows that pattern at
FS:[1C].
I guess I will simply remove the smp_cpus == 1 special case.
Jan
PS: Please strip of the newsgroups from CC when picking up a thread via
news.gmane.org. Some clients may not be configured to reply to them
(like mine - intentionally :) ).
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WARNING: multiple messages have this Message-ID (diff)
From: Jan Kiszka <jan.kiszka@web.de>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>,
kvm@vger.kernel.org, Gleb Natapov <gleb@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
qemu-devel <qemu-devel@nongnu.org>, Avi Kivity <avi@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 3/6] kvmvapic: Introduce TPR access optimization for Windows guests
Date: Thu, 09 Feb 2012 19:01:40 +0100 [thread overview]
Message-ID: <4F340A04.5080303@web.de> (raw)
In-Reply-To: <4F340066.9070108@redhat.com>
[-- Attachment #1: Type: text/plain, Size: 958 bytes --]
On 2012-02-09 18:20, Paolo Bonzini wrote:
> On 02/09/2012 05:32 PM, Jan Kiszka wrote:
>> > I mean just check kpcr.self.
>>
>> Yes, clear, but that means that Windows must have initialized FS.base to
>> point to the KPCR also in UP mode. Is that really the case? E.g. when
>> ACPI is off?! I wonder if that explains the reported bug of qemu-kvm
>> with -no-acpi and in-kernel irqchip...
>
> Yes, it does. It's used by some fast-path kernel APIs, and indeed the
> canonical way to find the KPCR base from ring 0 is to look at FS:[1Ch].
Yep, can confirm this so far. I briefly tested a non-ACPI installation,
and it both works without problems on qemu-kvm and shows that pattern at
FS:[1C].
I guess I will simply remove the smp_cpus == 1 special case.
Jan
PS: Please strip of the newsgroups from CC when picking up a thread via
news.gmane.org. Some clients may not be configured to reply to them
(like mine - intentionally :) ).
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next prev parent reply other threads:[~2012-02-09 18:01 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-05 12:39 [PATCH 0/6] uq/master: TPR access optimization for Windows guests Jan Kiszka
2012-02-05 12:39 ` [Qemu-devel] " Jan Kiszka
2012-02-05 12:39 ` [PATCH 1/6] target-i386: Add infrastructure for reporting TPR MMIO accesses Jan Kiszka
2012-02-05 12:39 ` [Qemu-devel] " Jan Kiszka
2012-02-05 12:39 ` [PATCH 2/6] kvmvapic: Add option ROM Jan Kiszka
2012-02-05 12:39 ` [Qemu-devel] " Jan Kiszka
2012-02-05 12:39 ` [PATCH 3/6] kvmvapic: Introduce TPR access optimization for Windows guests Jan Kiszka
2012-02-05 12:39 ` [Qemu-devel] " Jan Kiszka
2012-02-09 8:35 ` [Qemu-devel] subpages with memory region aliases (was: [PATCH 3/6] kvmvapic: Introduce TPR access optimization for Windows guests) Jan Kiszka
2012-02-09 9:32 ` [Qemu-devel] subpages with memory region aliases Avi Kivity
2012-02-09 14:23 ` Jan Kiszka
2012-02-09 15:05 ` Avi Kivity
2012-02-09 15:18 ` [PATCH 3/6] kvmvapic: Introduce TPR access optimization for Windows guests Avi Kivity
2012-02-09 15:18 ` [Qemu-devel] " Avi Kivity
2012-02-09 15:39 ` Jan Kiszka
2012-02-09 15:39 ` [Qemu-devel] " Jan Kiszka
2012-02-09 16:00 ` Avi Kivity
2012-02-09 16:00 ` [Qemu-devel] " Avi Kivity
2012-02-09 16:32 ` Jan Kiszka
2012-02-09 16:32 ` [Qemu-devel] " Jan Kiszka
2012-02-09 16:47 ` Avi Kivity
2012-02-09 16:47 ` [Qemu-devel] " Avi Kivity
2012-02-09 17:24 ` Jan Kiszka
2012-02-09 17:24 ` [Qemu-devel] " Jan Kiszka
2012-02-09 17:20 ` Paolo Bonzini
2012-02-09 17:20 ` [Qemu-devel] " Paolo Bonzini
2012-02-09 18:01 ` Jan Kiszka [this message]
2012-02-09 18:01 ` Jan Kiszka
2012-02-05 12:39 ` [PATCH 4/6] kvmvapic: Simplify mp/up_set_tpr Jan Kiszka
2012-02-05 12:39 ` [Qemu-devel] " Jan Kiszka
2012-02-05 12:39 ` [PATCH 5/6] optionsrom: Reserve space for checksum Jan Kiszka
2012-02-05 12:39 ` [Qemu-devel] " Jan Kiszka
2012-02-05 12:39 ` [PATCH 6/6] kvmvapic: Use optionrom helpers Jan Kiszka
2012-02-05 12:39 ` [Qemu-devel] " Jan Kiszka
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