From: Avi Kivity <avi@redhat.com>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>,
Gleb Natapov <gleb@redhat.com>,
kvm@vger.kernel.org, Marcelo Tosatti <mtosatti@redhat.com>,
qemu-devel <qemu-devel@nongnu.org>,
Blue Swirl <blauwirbel@gmail.com>
Subject: Re: [Qemu-devel] [PATCH v3 4/9] target-i386: Add infrastructure for reporting TPR MMIO accesses
Date: Thu, 16 Feb 2012 17:21:53 +0200 [thread overview]
Message-ID: <4F3D1F11.5070804@redhat.com> (raw)
In-Reply-To: <3ac2ae28b19aabebd3937b87ff365b481f990779.1329232393.git.jan.kiszka@siemens.com>
On 02/14/2012 05:13 PM, Jan Kiszka wrote:
> Note that KVM without in-kernel irqchip will report the address after
> the instruction that triggered a write access. In contrast, read
> accesses will return the precise information.
>
Well this is wierd. We could retro-doc one or the other behaviour, but
this-on-read-but-that-on-write is just too strange.
The documented way of dealing with this is to queue a signal and reenter
the guest. kvm will perform anything it needs to complete the
instruction (perhaps issuing more mmio, say if someone used movsd to
read the APIC) and then exit on the signal. By then rip will point
exactly after the instruction.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2012-02-16 15:22 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-14 15:13 [Qemu-devel] [PATCH v3 0/9] uq/master: TPR access optimization for Windows guests Jan Kiszka
2012-02-14 15:13 ` [Qemu-devel] [PATCH v3 1/9] kvm: Set cpu_single_env only once Jan Kiszka
2012-02-14 15:13 ` [Qemu-devel] [PATCH v3 2/9] Remove useless casts from cpu iterators Jan Kiszka
2012-02-14 15:13 ` [Qemu-devel] [PATCH v3 3/9] Allow to use pause_all_vcpus from VCPU context Jan Kiszka
2012-02-14 15:13 ` [Qemu-devel] [PATCH v3 4/9] target-i386: Add infrastructure for reporting TPR MMIO accesses Jan Kiszka
2012-02-16 15:21 ` Avi Kivity [this message]
2012-02-16 15:29 ` Jan Kiszka
2012-02-14 15:13 ` [Qemu-devel] [PATCH v3 5/9] kvmvapic: Add option ROM Jan Kiszka
2012-02-14 15:13 ` [Qemu-devel] [PATCH v3 6/9] kvmvapic: Introduce TPR access optimization for Windows guests Jan Kiszka
2012-02-16 15:29 ` Avi Kivity
2012-02-14 15:13 ` [Qemu-devel] [PATCH v3 7/9] kvmvapic: Simplify mp/up_set_tpr Jan Kiszka
2012-02-14 15:13 ` [Qemu-devel] [PATCH v3 8/9] optionsrom: Reserve space for checksum Jan Kiszka
2012-02-14 15:13 ` [Qemu-devel] [PATCH v3 9/9] kvmvapic: Use optionrom helpers Jan Kiszka
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