From: Avi Kivity <avi@redhat.com>
To: Sheng Yang <sheng@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
kvm@vger.kernel.org
Subject: Re: [PATCH 3/3] KVM: Add documents for MSI-X MMIO API
Date: Tue, 25 Jan 2011 14:47:38 +0200 [thread overview]
Message-ID: <4D3EC66A.2050207@redhat.com> (raw)
In-Reply-To: <201101191621.06840.sheng@linux.intel.com>
On 01/19/2011 10:21 AM, Sheng Yang wrote:
> > >
> > > We already got an guest MMIO address for that in the exit information.
> > > I've created a chain of handler in qemu to handle it.
> >
> > But we already decoded the table and entry...
>
> But the handler is still wrapped by vcpu_mmio_write(), as a part of MMIO. So it's
> not quite handy to get the table and entry out.
The kernel handler can create a new kvm_run exit description.
> Also the updater in the userspace
> can share the most logic with ordinary userspace MMIO handler, which take address
> as parameter. So I think we don't need to pass the decoded table_id and entry to
> userspace.
It's mixing layers, which always leads to trouble. For one, the user
handler shouldn't do anything with the write since the kernel already
wrote it into the table. For another, if two vcpus write to the same
entry simultaneously, you could see different ordering in the kernel and
userspace, and get inconsistent results.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2011-01-25 12:47 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-06 10:19 [PATCH 0/3 v7] MSI-X MMIO support for KVM Sheng Yang
2011-01-06 10:19 ` [PATCH 1/3] KVM: Move struct kvm_io_device to kvm_host.h Sheng Yang
2011-01-06 10:19 ` [PATCH 2/3] KVM: Emulate MSI-X table in kernel Sheng Yang
2011-01-17 11:54 ` Marcelo Tosatti
2011-01-17 12:18 ` Sheng Yang
2011-01-17 12:18 ` Avi Kivity
2011-01-17 12:48 ` Marcelo Tosatti
2011-01-17 12:51 ` Avi Kivity
2011-01-17 15:52 ` Marcelo Tosatti
2011-01-17 16:01 ` Avi Kivity
2011-01-17 12:39 ` Marcelo Tosatti
2011-01-19 8:37 ` Sheng Yang
2011-01-17 12:29 ` Avi Kivity
2011-01-17 13:31 ` Michael S. Tsirkin
2011-01-17 13:47 ` Jan Kiszka
2011-01-30 4:38 ` Sheng Yang
2011-01-31 13:09 ` Avi Kivity
2011-02-01 4:21 ` Sheng Yang
2011-01-06 10:19 ` [PATCH 3/3] KVM: Add documents for MSI-X MMIO API Sheng Yang
2011-01-17 12:21 ` Avi Kivity
2011-01-17 12:35 ` Sheng Yang
2011-01-17 12:45 ` Avi Kivity
2011-01-19 8:21 ` Sheng Yang
2011-01-25 12:47 ` Avi Kivity [this message]
2011-01-26 9:05 ` Sheng Yang
2011-01-31 13:24 ` Avi Kivity
2011-02-01 4:26 ` Sheng Yang
2011-01-12 2:23 ` [PATCH 0/3 v7] MSI-X MMIO support for KVM Sheng Yang
-- strict thread matches above, loose matches on Subject: below --
2011-01-30 5:11 [PATCH 0/3 v8] " Sheng Yang
2011-01-30 5:11 ` [PATCH 3/3] KVM: Add documents for MSI-X MMIO API Sheng Yang
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