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Re: [Qemu-devel] [PATCH v2 for-2.4 0/3] block: Improve warnings for doub
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [PATCH v2 for-2.4 0/3] block: Improve warnings for doubly-connected drives |
Date: |
Thu, 25 Jun 2015 14:23:21 +0100 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Tue, Jun 23, 2015 at 03:01:44PM +0100, Peter Maydell wrote:
> This patchset attempts to improve the warning and error messages for
> bad user command lines that attempt to connect a drive up to two
> devices. The motivation here is patch #4, which changes the default
> interface for the virt board to virtio. That will break some existing
> command lines which forgot to specify if=none, and so I would like
> us to at least diagnose that user error in a helpful way that points
> the user towards adding the missing if=none.
>
> Version 2 reduces scope, because it turns out that it is harder than
> we thought to identify whether a use of an if=something drive is the
> auto-plugging or a manual wiring up to a device. So all we do here
> is improve the error messages for two situations which were already
> errors but with rather cryptic messages:
>
> (1) Drive specified as to be auto-connected and also manually connected
> (and the board does handle this if= type):
>
> qemu-system-x86_64 -nodefaults -display none \
> -drive if=scsi,file=tmp.qcow2,id=foo -device ide-hd,drive=foo
>
> Previously:
> qemu-system-x86_64: -device ide-hd,drive=foo: Property 'ide-hd.drive'
> can't take value 'foo', it's in use
>
> Now:
> qemu-system-x86_64: -device ide-hd,drive=foo: Drive 'foo' is already in
> use because it has been automatically connected to another device (did
> you need 'if=none' in the drive options?)
>
> (2) Drive specified to be manually connected in two different ways:
>
> qemu-system-x86_64 -nodefaults -display none \
> -drive if=none,file=tmp.qcow2,id=foo -device ide-hd,drive=foo \
> -device ide-hd,drive=foo
>
> Previously:
> qemu-system-x86_64: -device ide-hd,drive=foo: Property 'ide-hd.drive'
> can't take value 'foo', it's in use
>
> Now:
> qemu-system-x86_64: -device ide-hd,drive=foo: Drive 'foo' is already in
> use by another device
>
> (We'll also produce message 1 in the oddball case where the user creates
> a drive if=something-not-handled-by-machine and then wires it up manually
> to two different devices; in this case their command line is doubly broken
> and if they use if=none as suggested by message 1 they'll then get message 2
> and can fix their own double-usage...)
>
> Changes v1->v2:
> * drop "warn if an if=<something> drive was also connected manually" patch
> * change implementation of "improve error message" patch
>
>
> Peter Maydell (3):
> qdev-properties-system: Change set_pointer's parse callback to use
> Error
> qdev-properties-system: Improve error message for drive assignment
> conflict
> hw/arm/virt: Make block devices default to virtio
>
> hw/arm/virt.c | 2 ++
> hw/core/qdev-properties-system.c | 42
> +++++++++++++++++++++++++++-------------
> 2 files changed, 31 insertions(+), 13 deletions(-)
>
> --
> 1.9.1
>
>
Reviewed-by: Stefan Hajnoczi <address@hidden>
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Re: [Qemu-devel] [PATCH v2 for-2.4 0/3] block: Improve warnings for doubly-connected drives,
Stefan Hajnoczi <=