Displaying 7 results from an estimated 7 matches for "0x4000002".
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0x400000
2014 Sep 18
3
Standardizing an MSR or other hypercall to get an RNG seed?
I'm not sure what you mean by "this mechanism?" Are you suggesting that each hypervisor put "CrossHVPara\0" somewhere in the 0x40000000 - 0x400fffff CPUID range, and an OS has to do a full scan of this CPUID range on boot to find it? That seems pretty inefficient. An OS will take 1000's of hypervisor intercepts on every boot just to search this CPUID range.
I
2014 Sep 18
3
Standardizing an MSR or other hypercall to get an RNG seed?
I'm not sure what you mean by "this mechanism?" Are you suggesting that each hypervisor put "CrossHVPara\0" somewhere in the 0x40000000 - 0x400fffff CPUID range, and an OS has to do a full scan of this CPUID range on boot to find it? That seems pretty inefficient. An OS will take 1000's of hypervisor intercepts on every boot just to search this CPUID range.
I
2014 Sep 18
0
Standardizing an MSR or other hypercall to get an RNG seed?
...implement this range), but that would require Linux to look in that range on boot to discover this capability.
I also don't know whether QEMU and KVM would be okay with implementing
the host side of the Hyper-V mechanism by default. They would have to
implement at least leaves 0x40000001 and 0x4000002, plus correctly
reporting zeros through whatever leaf is used for this new feature.
Gleb? Paolo?
--Andy
2014 Sep 19
2
Standardizing an MSR or other hypercall to get an RNG seed?
...e), but that would require Linux to look in that range on boot to discover this capability.
>
> I also don't know whether QEMU and KVM would be okay with implementing
> the host side of the Hyper-V mechanism by default. They would have to
> implement at least leaves 0x40000001 and 0x4000002, plus correctly
> reporting zeros through whatever leaf is used for this new feature.
> Gleb? Paolo?
>
KVM and any other hypervisor out there already implement capability
detection mechanism in 0x40000000 range, and of course all of them do
it differently. Linux detects what hypervior it...
2014 Sep 19
2
Standardizing an MSR or other hypercall to get an RNG seed?
...e), but that would require Linux to look in that range on boot to discover this capability.
>
> I also don't know whether QEMU and KVM would be okay with implementing
> the host side of the Hyper-V mechanism by default. They would have to
> implement at least leaves 0x40000001 and 0x4000002, plus correctly
> reporting zeros through whatever leaf is used for this new feature.
> Gleb? Paolo?
>
KVM and any other hypervisor out there already implement capability
detection mechanism in 0x40000000 range, and of course all of them do
it differently. Linux detects what hypervior it...
2014 Sep 18
5
Standardizing an MSR or other hypercall to get an RNG seed?
On Thu, Sep 18, 2014 at 11:58 AM, Paolo Bonzini <pbonzini at redhat.com> wrote:
>
>> > Actually, that MSR address range has been reserved for that purpose, along
>> > with:
>> > - CPUID.EAX=1 -> ECX bit 31 (always returns 0 on bare metal)
>> > - CPUID.EAX=4000_00xxH leaves (i.e. HYPERVISOR CPUID)
>>
>> I don't know whether this is
2014 Sep 18
5
Standardizing an MSR or other hypercall to get an RNG seed?
On Thu, Sep 18, 2014 at 11:58 AM, Paolo Bonzini <pbonzini at redhat.com> wrote:
>
>> > Actually, that MSR address range has been reserved for that purpose, along
>> > with:
>> > - CPUID.EAX=1 -> ECX bit 31 (always returns 0 on bare metal)
>> > - CPUID.EAX=4000_00xxH leaves (i.e. HYPERVISOR CPUID)
>>
>> I don't know whether this is