[PATCH] i386: Document when features can be added to kvm_default_props

[PATCH] i386: Document when features can be added to kvm_default_props

[Eduardo Habkost]

It's very easy to mistakenly extend kvm_default_props to include
features that require a kernel version that's too recent.  Add a
comment warning about that, pointing to the documentation file
where the minimum kernel version for KVM is documented.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 target/i386/cpu.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 3ffd877dd51..c8558bb49ac 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -4098,8 +4098,14 @@ static X86CPUDefinition builtin_x86_defs[] = {
     },
 };
 
-/* KVM-specific features that are automatically added/removed
+/*
+ * KVM-specific features that are automatically added/removed
  * from all CPU models when KVM is enabled.
+ *
+ * NOTE: features can be enabled by default only if they were
+ *       already available in the oldest kernel version supported
+ *       by the KVM accelerator (see "OS requirements" section at
+ *       docs/system/target-i386.rst)
  */
 static PropValue kvm_default_props[] = {
     { "kvmclock", "on" },
-- 
2.26.2

Re: [PATCH] i386: Document when features can be added to kvm_default_props

[Paolo Bonzini]

On 25/09/20 23:10, Eduardo Habkost wrote:
> It's very easy to mistakenly extend kvm_default_props to include
> features that require a kernel version that's too recent.  Add a
> comment warning about that, pointing to the documentation file
> where the minimum kernel version for KVM is documented.
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
>  target/i386/cpu.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index 3ffd877dd51..c8558bb49ac 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -4098,8 +4098,14 @@ static X86CPUDefinition builtin_x86_defs[] = {
>      },
>  };
>  
> -/* KVM-specific features that are automatically added/removed
> +/*
> + * KVM-specific features that are automatically added/removed
>   * from all CPU models when KVM is enabled.
> + *
> + * NOTE: features can be enabled by default only if they were
> + *       already available in the oldest kernel version supported
> + *       by the KVM accelerator (see "OS requirements" section at
> + *       docs/system/target-i386.rst)
>   */
>  static PropValue kvm_default_props[] = {
>      { "kvmclock", "on" },
> 

Acked-by: Paolo Bonzini <pbonzini@redhat.com>

Re: [PATCH] i386: Document when features can be added to kvm_default_props

[no-reply]

Patchew URL: https://patchew.org/QEMU/20200925211021.4158567-1-ehabkost@redhat.com/



Hi,

This series failed the docker-quick@centos7 build test. Please find the testing commands and
their output below. If you have Docker installed, you can probably reproduce it
locally.

=== TEST SCRIPT BEGIN ===
#!/bin/bash
make docker-image-centos7 V=1 NETWORK=1
time make docker-test-quick@centos7 SHOW_ENV=1 J=14 NETWORK=1
=== TEST SCRIPT END ===

C linker for the host machine: cc ld.bfd 2.27-43
Host machine cpu family: x86_64
Host machine cpu: x86_64
../src/meson.build:10: WARNING: Module unstable-keyval has no backwards or forwards compatibility and might not exist in future releases.
Program sh found: YES
Program python3 found: YES (/usr/bin/python3)
Configuring ninjatool using configuration
---
  TEST    iotest-qcow2: 024
socket_accept failed: Resource temporarily unavailable
**
ERROR:../src/tests/qtest/libqtest.c:301:qtest_init_without_qmp_handshake: assertion failed: (s->fd >= 0 && s->qmp_fd >= 0)
../src/tests/qtest/libqtest.c:166: kill_qemu() tried to terminate QEMU process but encountered exit status 1 (expected 0)
ERROR qtest-aarch64: bios-tables-test - Bail out! ERROR:../src/tests/qtest/libqtest.c:301:qtest_init_without_qmp_handshake: assertion failed: (s->fd >= 0 && s->qmp_fd >= 0)
make: *** [run-test-159] Error 1
make: *** Waiting for unfinished jobs....
  TEST    iotest-qcow2: 025
  TEST    iotest-qcow2: 027
---
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['sudo', '-n', 'docker', 'run', '--rm', '--label', 'com.qemu.instance.uuid=1bf1802df7d443929b92e9534e4a83ff', '-u', '1003', '--security-opt', 'seccomp=unconfined', '-e', 'TARGET_LIST=', '-e', 'EXTRA_CONFIGURE_OPTS=', '-e', 'V=', '-e', 'J=14', '-e', 'DEBUG=', '-e', 'SHOW_ENV=1', '-e', 'CCACHE_DIR=/var/tmp/ccache', '-v', '/home/patchew2/.cache/qemu-docker-ccache:/var/tmp/ccache:z', '-v', '/var/tmp/patchew-tester-tmp-q5cgi4gp/src/docker-src.2020-09-25-20.07.00.10236:/var/tmp/qemu:z,ro', 'qemu/centos7', '/var/tmp/qemu/run', 'test-quick']' returned non-zero exit status 2.
filter=--filter=label=com.qemu.instance.uuid=1bf1802df7d443929b92e9534e4a83ff
make[1]: *** [docker-run] Error 1
make[1]: Leaving directory `/var/tmp/patchew-tester-tmp-q5cgi4gp/src'
make: *** [docker-run-test-quick@centos7] Error 2

real    18m15.588s
user    0m16.838s


The full log is available at
http://patchew.org/logs/20200925211021.4158567-1-ehabkost@redhat.com/testing.docker-quick@centos7/?type=message.
---
Email generated automatically by Patchew [https://patchew.org/].
Please send your feedback to patchew-devel@redhat.com

Re: [PATCH] i386: Document when features can be added to kvm_default_props

[Eduardo Habkost]

On Fri, Sep 25, 2020 at 05:10:21PM -0400, Eduardo Habkost wrote:
> It's very easy to mistakenly extend kvm_default_props to include
> features that require a kernel version that's too recent.  Add a
> comment warning about that, pointing to the documentation file
> where the minimum kernel version for KVM is documented.
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

I forgot about this.  I'm queueing it now (7 months later).

-- 
Eduardo