On 15.11.2010, at 15:47, Anthony PERARD wrote:
> On Mon, 15 Nov 2010, Anthony PERARD wrote:
>
>> On Mon, 15 Nov 2010, Alexander Graf wrote:
>>
>>>
>>> On 21.10.2010, at 19:36, Anthony.Perard@xxxxxxxxxx wrote:
>>>
>>>> From: Anthony PERARD <anthony.perard@xxxxxxxxxx>
>>>>
>>>> This option gives the ability to switch one "accelerator" like kvm, xen
>>>> or the default one tcg. We can specify more than one accelerator by
>>>> separate them by a comma. QEMU will try each one and use the first whose
>>>> works.
>>>>
>>>> So,
>>>>
>>>> -accel xen,kvm,tcg
>>>>
>>>> which would try Xen support first, then KVM and finaly tcg if none of
>>>> the other works.
>>>>
>>>> Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
>>>> ---
>>>> qemu-options.hx | 10 ++++++
>>>> vl.c | 86
>>>> ++++++++++++++++++++++++++++++++++++++++++++++++-------
>>>> 2 files changed, 85 insertions(+), 11 deletions(-)
>>>>
>>>> diff --git a/vl.c b/vl.c
>>>> index df414ef..40a26ee 100644
>>>> --- a/vl.c
>>>> +++ b/vl.c
>>>> @@ -1750,6 +1750,74 @@ static int debugcon_parse(const char *devname)
>>>> return 0;
>>>> }
>>>>
>>>> +static struct {
>>>> + const char *opt_name;
>>>> + const char *name;
>>>> + int (*available)(void);
>>>> + int (*init)(int smp_cpus);
>>>> + int *allowed;
>>>> +} accel_list[] = {
>>>> + { "tcg", "tcg", NULL, NULL, NULL },
>>>> + { "kvm", "KVM", kvm_available, kvm_init, &kvm_allowed },
>>>
>>> Thinking about this a bit more ...
>>>
>>> kvm_available is a function pointer that gets #defined to (0) when we don't
>>> have KVM available. I can imagine some compiler might throw a warning on us
>>> for this one day.
>>>
>>> Is there a valid reason not to do
>>>
>>> static inline int kvm_enabled()
>>> {
>>> #ifdef CONFIG_KVM
>>> return kvm_allowed;
>>> #else
>>> return 0;
>>> #endif
>>> }
>>>
>>> That should compile into the exact same code but be valid for function
>>> pointers.
>>
>> I will do this change, as well as for the two others patches.
>
> Actually, kvm_available is already a function, not a define.
>
> kvm_enable can be change from define to function, but not in this patch,
> because I don't use it.
Oh no worries for stuff you don't use. As long as kvm_available is a function,
just make sure that xen_available is one too :). The main incentive is to get
rid of all those if (!x->available) parts, as we can guarantee there to always
be a function behind.
Treating tcg the same way would also help in the long term for non-tcg build of
qemu which some people are interested in ;).
Alex
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