>>> On Wed, May 16, 2007 at 7:47 AM, in message <[EMAIL PROTECTED]>,
Avi Kivity <[EMAIL PROTECTED]> wrote:
> Gregory Haskins wrote:
>> Newer userspace may run on an older kernel. Therefore we need a way to
>> check the capabilities of the kernel so that we can downgrade userspace
>> dynamically if necessary
>>
>> Signed- off- by: Gregory Haskins <[EMAIL PROTECTED]>
>> ---
>>
>> qemu/qemu- kvm.c | 19 +++++++++++++++++++
>> user/kvmctl.c | 14 ++++++++++++++
>> user/kvmctl.h | 5 +++++
>> 3 files changed, 38 insertions(+), 0 deletions(- )
>>
>> diff -- git a/qemu/qemu- kvm.c b/qemu/qemu- kvm.c
>> index 59e79bf..6096f21 100644
>> --- a/qemu/qemu- kvm.c
>> +++ b/qemu/qemu- kvm.c
>> @@ - 697,6 +697,25 @@ int kvm_qemu_init()
>> int kvm_qemu_create_context(void)
>> {
>> int i;
>> + uint64_t ext;
>> +
>> + if (kvm_check_extension(kvm_context, &ext) < 0) {
>> + kvm_qemu_destroy();
>> + return - 1;
>> + }
>> +
>> + if (!(ext & KVM_EXTENSION_LAPIC) && kvm_apic_level) {
>> + /*
>> + * Opps... the kernel doesnt support apic- emulation even though
>> + * the user wants it. We must turn this off and warn the user
>> + */
>> + kvm_apic_level = 0;
>> +
>> + /* FIXME: We should log this officially */
>> + printf("WARNING: older kernel does not support apic " \
>> + "emulation. Falling back to userspace emulation. Upgrade " \
>> + "your kernel/modules\n");
>> + }
>>
>
> The user may not be in a position to upgrade the kernel. Think distro
> kernel and userspace. A warning is a bit severe.
Ack. Should I drop the printf all together? Or just get rid of the "WARNING"
and "please upgrade" part?. Also, is there a better way to log in this thing
(instead of to stdout?)
All the rest of your comments: Ack.
>
>>
>> if (kvm_create(kvm_context, phys_ram_size, kvm_apic_level,
>> (void**)&phys_ram_base) < 0) {
>> diff -- git a/user/kvmctl.c b/user/kvmctl.c
>> index ea86426..fcabc1a 100644
>> --- a/user/kvmctl.c
>> +++ b/user/kvmctl.c
>> @@ - 889,3 +889,17 @@ int kvm_set_signal_mask(kvm_context_t kvm, int vcpu,
> const sigset_t *sigset)
>> free(sigmask);
>> return r;
>> }
>> +
>> +int kvm_check_extension(kvm_context_t kvm, uint64_t *ext)
>> +{
>> + *ext = 0;
>> +
>> + int r = ioctl(kvm- >fd, KVM_CHECK_EXTENSION, KVM_APIC_MSG);
>> + if (r < 0)
>> + return r;
>>
>
> - errno for new code, please.
>
>> +
>> + if (r)
>> + *ext |= KVM_EXTENSION_LAPIC;
>> +
>> + return 0;
>> +}
>>
>
> How about a struct with a field per extension instead of bitmasks?
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