[PATCH] docs: stop documenting the e1000 NIC model as the default

[PATCH] docs: stop documenting the e1000 NIC model as the default

[Daniel P. Berrangé]

The default NIC model for QEMU varies per machine type, and is liable to
change across machine type versions. Documenting e1000 NIC as the
default for PC/i386 is thus misleading to users at best. In particular
the PC q35 machine type switched to use e1000e, but only in machine
type versions after 2.11.

Rather than try to explain which NIC model is used for each machine
type version, remove mention of e1000 as the default, and steer users
towards always specifying their desired model.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 qemu-options.hx | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/qemu-options.hx b/qemu-options.hx
index e9d6231438..ca57145126 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2344,8 +2344,7 @@ Use @option{model=help} to list the available device types.
 The hardware MAC address can be set with @option{mac=@var{macaddr}}.
 
 The following two example do exactly the same, to show how @option{-nic} can
-be used to shorten the command line length (note that the e1000 is the default
-on i386, so the @option{model=e1000} parameter could even be omitted here, too):
+be used to shorten the command line length:
 @example
 @value{qemu_system} -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32
 @value{qemu_system} -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32
@@ -2759,9 +2758,12 @@ netdev with ID @var{nd} by using the @option{netdev=@var{nd}} option.
 Legacy option to configure or create an on-board (or machine default) Network
 Interface Card(NIC) and connect it either to the emulated hub with ID 0 (i.e.
 the default hub), or to the netdev @var{nd}.
-The NIC is an e1000 by default on the PC target. Optionally, the MAC address
-can be changed to @var{mac}, the device address set to @var{addr} (PCI cards
-only), and a @var{name} can be assigned for use in monitor commands.
+If @var{model} is omitted, then the default NIC model associated with
+the machine type is used. Note that the default NIC model may change in
+future QEMU releases, so it is highly recommended to always specify a model.
+Optionally, the MAC address can be changed to @var{mac}, the device
+address set to @var{addr} (PCI cards only), and a @var{name} can be
+assigned for use in monitor commands.
 Optionally, for PCI cards, you can specify the number @var{v} of MSI-X vectors
 that the card should have; this option currently only affects virtio cards; set
 @var{v} = 0 to disable MSI-X. If no @option{-net} option is specified, a single
-- 
2.23.0

Re: [PATCH] docs: stop documenting the e1000 NIC model as the default

[Aleksandar Markovic]

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On Thursday, January 9, 2020, Daniel P. Berrangé <berrange@redhat.com>
wrote:

> The default NIC model for QEMU varies per machine type, and is liable to
> change across machine type versions. Documenting e1000 NIC as the
> default for PC/i386 is thus misleading to users at best. In particular
> the PC q35 machine type switched to use e1000e, but only in machine
> type versions after 2.11.
>
> Rather than try to explain which NIC model is used for each machine
> type version, remove mention of e1000 as the default, and steer users
> towards always specifying their desired model.
>
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
>  qemu-options.hx | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
>
>
Reviewed by: Aleksandar Markovic <amarkovic@wavecomp.com>



> diff --git a/qemu-options.hx b/qemu-options.hx
> index e9d6231438..ca57145126 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -2344,8 +2344,7 @@ Use @option{model=help} to list the available device
> types.
>  The hardware MAC address can be set with @option{mac=@var{macaddr}}.
>
>  The following two example do exactly the same, to show how @option{-nic}
> can
> -be used to shorten the command line length (note that the e1000 is the
> default
> -on i386, so the @option{model=e1000} parameter could even be omitted
> here, too):
> +be used to shorten the command line length:
>  @example
>  @value{qemu_system} -netdev user,id=n1,ipv6=off -device
> e1000,netdev=n1,mac=52:54:98:76:54:32
>  @value{qemu_system} -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32
> @@ -2759,9 +2758,12 @@ netdev with ID @var{nd} by using the
> @option{netdev=@var{nd}} option.
>  Legacy option to configure or create an on-board (or machine default)
> Network
>  Interface Card(NIC) and connect it either to the emulated hub with ID 0
> (i.e.
>  the default hub), or to the netdev @var{nd}.
> -The NIC is an e1000 by default on the PC target. Optionally, the MAC
> address
> -can be changed to @var{mac}, the device address set to @var{addr} (PCI
> cards
> -only), and a @var{name} can be assigned for use in monitor commands.
> +If @var{model} is omitted, then the default NIC model associated with
> +the machine type is used. Note that the default NIC model may change in
> +future QEMU releases, so it is highly recommended to always specify a
> model.
> +Optionally, the MAC address can be changed to @var{mac}, the device
> +address set to @var{addr} (PCI cards only), and a @var{name} can be
> +assigned for use in monitor commands.
>  Optionally, for PCI cards, you can specify the number @var{v} of MSI-X
> vectors
>  that the card should have; this option currently only affects virtio
> cards; set
>  @var{v} = 0 to disable MSI-X. If no @option{-net} option is specified, a
> single
> --
> 2.23.0
>
>
>

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Re: [PATCH] docs: stop documenting the e1000 NIC model as the default

[Thomas Huth]

On 09/01/2020 13.29, Daniel P. Berrangé wrote:
> The default NIC model for QEMU varies per machine type, and is liable to
> change across machine type versions. Documenting e1000 NIC as the
> default for PC/i386 is thus misleading to users at best. In particular
> the PC q35 machine type switched to use e1000e, but only in machine
> type versions after 2.11.
> 
> Rather than try to explain which NIC model is used for each machine
> type version, remove mention of e1000 as the default, and steer users
> towards always specifying their desired model.
> 
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
>  qemu-options.hx | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)

Reviewed-by: Thomas Huth <thuth@redhat.com>