Hi!
>> - /*
>> - * Xen emulates Hyper-V to support enlightened Windows.
>> - * Check to see first if we are on a Xen Hypervisor.
>> - */
>> - if (xen_cpuid_base())
>> - return false;
. . .
>> void hv_register_vmbus_handler(int irq, irq_handler_t handler)
>> {
>> + /*
>> + * Setup the IDT for hypervisor callback.
>> + */
>> + alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
>> +
Michael S. Tsirkin> Any chance we can fast-path this patch into 3.9 so
Michael S. Tsirkin> that we don't release a kernel with hyper-v on Xen completely disabled?
Yes, this backport from linux-next ( future 3.10 ) to 3.9 ( on 2013-04-18 -- 3.9-rc(7+N) ) look like usefull . . .
Please, apply patch both 3.10 and 3.9
Best regards, Victor Miasnikov
Blog: http://vvm.blog.tut.by/
----- Original Message -----
From: "Michael S. Tsirkin"
To: "K. Y. Srinivasan"
Cc:
Sent: Thursday, April 18, 2013 5:17 PM
Subject: Re: [PATCH 1/1] X86: Handle Xen emulation of Hyper-V more gracefully
> On Thu, Apr 18, 2013 at 08:44:46AM -0700, K. Y. Srinivasan wrote:
>> Install the Hyper-V specific interrupt handler only when needed. This would
>> permit us to get rid of the Xen check. Note that when the vmbus drivers invokes
>> the call to register its handler, we are sure to be running on Hyper-V.
>>
>> Signed-off-by: K. Y. Srinivasan
>
> Looks good to me, this will address the concern. FWIW
>
> Acked-by: Michael S. Tsirkin
>
> Any chance we can fast-path this patch into 3.9 so that we don't release
> a kernel with hyper-v on Xen completely disabled?
>
>> ---
. . .
>> - /*
>> - * Xen emulates Hyper-V to support enlightened Windows.
>> - * Check to see first if we are on a Xen Hypervisor.
>> - */
>> - if (xen_cpuid_base())
>> - return false;
>> -
>> cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
>> &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
>>
>> @@ -82,12 +75,6 @@ static void __init ms_hyperv_init_platform(void)
>>
>> if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
>> clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
>> -#if IS_ENABLED(CONFIG_HYPERV)
>> - /*
>> - * Setup the IDT for hypervisor callback.
>> - */
>> - alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
>> -#endif
>> }
. . .
>> void hv_register_vmbus_handler(int irq, irq_handler_t handler)
>> {
>> + /*
>> + * Setup the IDT for hypervisor callback.
>> + */
>> + alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
>> +
>> vmbus_irq = irq;
. . .
>>