From: Stefan Hajnoczi <stefanha@gmail.com>
To: Haozhong Zhang <haozhong.zhang@intel.com>
Cc: qemu-devel@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>,
Igor Mammedov <imammedo@redhat.com>,
Xiao Guangrong <guangrong.xiao@gmail.com>,
Dan Williams <dan.j.williams@intel.com>
Subject: Re: [Qemu-devel] [PATCH v2 3/4] nvdimm: add a boolean option "restrict"
Date: Wed, 7 Jun 2017 16:27:49 +0100 [thread overview]
Message-ID: <20170607152749.GF21990@stefanha-x1.localdomain> (raw)
In-Reply-To: <20170606072229.9302-4-haozhong.zhang@intel.com>
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On Tue, Jun 06, 2017 at 03:22:28PM +0800, Haozhong Zhang wrote:
> If a vNVDIMM device is not backed by a DAX device and its "restrict"
> option is enabled, bit 3 of state flags in its region mapping
> structure will be set, in order to notify the guest of the lack of
> write persistence guarantee. Once this bit is set, the guest OS may
> mark the vNVDIMM device as read-only.
>
> This option is disabled by default for backwards compatibility. It's
> recommended to enable for the formal usage.
Good idea. I think the following is cleaner:
DEFINE_PROP_ON_OFF_AUTO("readonly") on the 'nvdimm' device. The
following states are available:
* 'on' - ACPI_NFIT_MEM_NOT_ARMED is set
* 'off' - ACPI_NFIT_MEM_NOT_ARMED is clear
* 'auto' - ACPI_NFIT_MEM_NOT_ARMED set if backend is not persistent
This new property defaults to 'auto'. Machine types older than
pc-i440fx-2.10 and pc-q35-2.10 default to 'on'.
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next prev parent reply other threads:[~2017-06-07 15:27 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-06 7:22 [Qemu-devel] [PATCH v2 0/4] nvdimm: fixes for (non-)dax backends Haozhong Zhang
2017-06-06 7:22 ` [Qemu-devel] [PATCH v2 1/4] nvdimm: add a macro for property "label-size" Haozhong Zhang
2017-06-07 15:29 ` Stefan Hajnoczi
2017-06-06 7:22 ` [Qemu-devel] [PATCH v2 2/4] nvdimm: warn if the backend is not a DAX device Haozhong Zhang
2017-06-06 17:59 ` Dan Williams
2017-06-08 1:07 ` Haozhong Zhang
2017-06-07 15:14 ` Stefan Hajnoczi
2017-06-08 1:07 ` Haozhong Zhang
2017-06-08 12:51 ` Michael S. Tsirkin
2017-06-12 3:18 ` Haozhong Zhang
2017-06-12 3:25 ` Michael S. Tsirkin
2017-06-06 7:22 ` [Qemu-devel] [PATCH v2 3/4] nvdimm: add a boolean option "restrict" Haozhong Zhang
2017-06-07 15:27 ` Stefan Hajnoczi [this message]
2017-06-08 1:45 ` Haozhong Zhang
2017-06-08 10:19 ` Stefan Hajnoczi
2017-06-08 6:39 ` Haozhong Zhang
2017-06-08 10:18 ` Stefan Hajnoczi
2017-06-08 12:56 ` Michael S. Tsirkin
2017-06-09 9:34 ` Stefan Hajnoczi
2017-06-12 1:18 ` Haozhong Zhang
2017-06-06 7:22 ` [Qemu-devel] [PATCH v2 4/4] util/mmap-alloc: account for DAX device in qemu_fd_getpagesize Haozhong Zhang
2017-06-07 15:29 ` Stefan Hajnoczi
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