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Re: [PATCH v3 02/16] libqos: read QVIRTIO_MMIO_VERSION register
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From: |
Thomas Huth |
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Subject: |
Re: [PATCH v3 02/16] libqos: read QVIRTIO_MMIO_VERSION register |
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Date: |
Mon, 21 Oct 2019 11:13:26 +0200 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 |
On 19/10/2019 08.37, Stefan Hajnoczi wrote:
> There was no real virtio-mmio ABI change between Legacy and VIRTIO 1.0
> except that the Version field was incremented from 1 to 2.
>
> However, QEMU does not allow Legacy drivers to perform VIRTIO 1.0
> operations like accessing 64-bit feature bits. Since we will introduce
> 64-bit feature bit support we need a way to differentiate between
> virtio-mmio Version 1 and 2 to avoid upsetting QEMU when we operate in
> Legacy mode.
>
> Stash away the Version field so later patches can change behavior
> depending on the version.
>
> Signed-off-by: Stefan Hajnoczi <address@hidden>
> ---
> tests/libqos/virtio-mmio.h | 1 +
> tests/libqos/virtio-mmio.c | 3 +++
> 2 files changed, 4 insertions(+)
Reviewed-by: Thomas Huth <address@hidden>
- [PATCH v3 00/16] libqos: add VIRTIO PCI 1.0 support, Stefan Hajnoczi, 2019/10/19
- [PATCH v3 01/16] tests/virtio-blk-test: read config space after feature negotiation, Stefan Hajnoczi, 2019/10/19
- [PATCH v3 02/16] libqos: read QVIRTIO_MMIO_VERSION register, Stefan Hajnoczi, 2019/10/19
- Re: [PATCH v3 02/16] libqos: read QVIRTIO_MMIO_VERSION register,
Thomas Huth <=
- [PATCH v3 03/16] libqos: extend feature bits to 64-bit, Stefan Hajnoczi, 2019/10/19
- [PATCH v3 04/16] virtio-scsi-test: add missing feature negotiation, Stefan Hajnoczi, 2019/10/19
- [PATCH v3 05/16] tests/virtio-blk-test: set up virtqueue after feature negotiation, Stefan Hajnoczi, 2019/10/19
- [PATCH v3 06/16] libqos: add missing virtio-9p feature negotiation, Stefan Hajnoczi, 2019/10/19