From: "Jan Beulich" <JBeulich@suse.com>
To: "KY Srinivasan" <kys@microsoft.com>
Cc: "olaf@aepfle.de" <olaf@aepfle.de>, "bp@alien8.de" <bp@alien8.de>,
"apw@canonical.com" <apw@canonical.com>,
"x86@kernel.org" <x86@kernel.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"devel@linuxdriverproject.org" <devel@linuxdriverproject.org>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"jasowang@redhat.com" <jasowang@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"hpa@zytor.com" <hpa@zytor.com>
Subject: RE: [PATCH RESEND 1/1] X86: Handle Hyper-V vmbus interrupts as special hypervisor interrupts
Date: Thu, 24 Jan 2013 16:15:30 +0000 [thread overview]
Message-ID: <51016C3202000078000B943E@nat28.tlf.novell.com> (raw)
In-Reply-To: <27092660926e4d3f80394697cc0dc858@SN2PR03MB061.namprd03.prod.outlook.com>
>>> On 24.01.13 at 17:07, KY Srinivasan <kys@microsoft.com> wrote:
>
>> -----Original Message-----
>> From: Jan Beulich [mailto:JBeulich@suse.com]
>> Sent: Thursday, January 24, 2013 3:48 AM
>> To: KY Srinivasan
>> Cc: olaf@aepfle.de; bp@alien8.de; apw@canonical.com; x86@kernel.org;
>> tglx@linutronix.de; devel@linuxdriverproject.org;
> gregkh@linuxfoundation.org;
>> jasowang@redhat.com; linux-kernel@vger.kernel.org; hpa@zytor.com
>> Subject: Re: [PATCH RESEND 1/1] X86: Handle Hyper-V vmbus interrupts as
>> special hypervisor interrupts
>>
>> >>> On 24.01.13 at 02:17, "K. Y. Srinivasan" <kys@microsoft.com> wrote:
>> > @@ -69,6 +74,11 @@ static void __init ms_hyperv_init_platform(void)
>> > ms_hyperv.features, ms_hyperv.hints);
>> >
>> > clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
>> > +
>> > + /*
>> > + * Setup the IDT for hypervisor callback.
>> > + */
>> > + alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR,
>> hyperv_callback_vector);
>>
>> Isn't doing this unconditionally here as problematic as the call to
>> clocksource_register_hz() turned out to be when Xen's Hyper-V
>> shim reacts to the CPUID inquiry above?
>
> I was not sure what to make this conditional on at run-time. To the extent
> that Xen emulation of Hyper-V is complete, this will be a problem. Does Xen
> return all the "feature bits" of Hyper-V. I could discriminate on a feature
> that
> Xen does not plan to emulate.
I've no idea what plans there might be, but that's the code
there is currently:
int cpuid_viridian_leaves(unsigned int leaf, unsigned int *eax,
unsigned int *ebx, unsigned int *ecx,
unsigned int *edx)
{
struct domain *d = current->domain;
if ( !is_viridian_domain(d) )
return 0;
leaf -= 0x40000000;
if ( leaf > 6 )
return 0;
*eax = *ebx = *ecx = *edx = 0;
switch ( leaf )
{
case 0:
*eax = 0x40000006; /* Maximum leaf */
*ebx = 0x7263694d; /* Magic numbers */
*ecx = 0x666F736F;
*edx = 0x76482074;
break;
case 1:
*eax = 0x31237648; /* Version number */
break;
case 2:
/* Hypervisor information, but only if the guest has set its
own version number. */
if ( d->arch.hvm_domain.viridian.guest_os_id.raw == 0 )
break;
*eax = 1; /* Build number */
*ebx = (xen_major_version() << 16) | xen_minor_version();
*ecx = 0; /* SP */
*edx = 0; /* Service branch and number */
break;
case 3:
/* Which hypervisor MSRs are available to the guest */
*eax = (CPUID3A_MSR_APIC_ACCESS |
CPUID3A_MSR_HYPERCALL |
CPUID3A_MSR_VP_INDEX);
break;
case 4:
/* Recommended hypercall usage. */
if ( (d->arch.hvm_domain.viridian.guest_os_id.raw == 0) ||
(d->arch.hvm_domain.viridian.guest_os_id.fields.os < 4) )
break;
*eax = (CPUID4A_MSR_BASED_APIC |
CPUID4A_RELAX_TIMER_INT);
*ebx = 2047; /* long spin count */
break;
}
return 1;
}
Question is - considering you stated that this is supported
starting in Win8, doesn't Hyper-V itself announce that
capability in some explicit way?
Jan
next prev parent reply other threads:[~2013-01-24 16:15 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-24 1:17 [PATCH RESEND 1/1] X86: Handle Hyper-V vmbus interrupts as special hypervisor interrupts K. Y. Srinivasan
2013-01-24 8:48 ` Jan Beulich
2013-01-24 16:07 ` KY Srinivasan
2013-01-24 16:15 ` Jan Beulich [this message]
2013-01-24 18:48 ` KY Srinivasan
2013-01-24 18:59 ` Olaf Hering
2013-01-24 19:03 ` KY Srinivasan
2013-01-25 7:32 ` Jan Beulich
2013-01-24 19:04 ` H. Peter Anvin
2013-01-24 19:23 ` Olaf Hering
2013-01-24 19:30 ` H. Peter Anvin
2013-01-25 7:30 ` Jan Beulich
2013-01-25 7:35 ` Jan Beulich
2013-01-25 13:58 ` Olaf Hering
2013-01-24 19:10 ` H. Peter Anvin
2013-01-25 7:31 ` Jan Beulich
-- strict thread matches above, loose matches on Subject: below --
2013-01-24 1:56 K. Y. Srinivasan
2013-01-24 9:28 ` Borislav Petkov
2013-01-24 12:11 ` H. Peter Anvin
2013-01-24 17:35 ` Borislav Petkov
2013-01-24 17:36 ` H. Peter Anvin
2013-01-24 17:42 ` KY Srinivasan
2013-01-18 1:55 K. Y. Srinivasan
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