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From: Wei Liu <wei.liu@kernel.org>
To: "Enrico Weigelt, metux IT consult" <lkml@metux.net>
Cc: Wei Liu <wei.liu@kernel.org>,
	Linux on Hyper-V List <linux-hyperv@vger.kernel.org>,
	virtualization@lists.linux-foundation.org,
	Linux Kernel List <linux-kernel@vger.kernel.org>,
	Michael Kelley <mikelley@microsoft.com>,
	Vineeth Pillai <viremana@linux.microsoft.com>,
	Sunil Muthuswamy <sunilmut@microsoft.com>,
	Nuno Das Neves <nunodasneves@linux.microsoft.com>,
	sameo@linux.intel.com, robert.bradford@intel.com,
	sebastien.boeuf@intel.com
Subject: Re: [PATCH v3 00/17] Introducing Linux root partition support for Microsoft Hypervisor
Date: Tue, 15 Dec 2020 16:42:45 +0000	[thread overview]
Message-ID: <20201215164245.yrorpipw2476w35e@liuwe-devbox-debian-v2> (raw)
In-Reply-To: <87d94c39-e801-fbc6-8f7f-1f1b00fa719d@metux.net>

On Tue, Dec 15, 2020 at 04:25:03PM +0100, Enrico Weigelt, metux IT consult wrote:
> On 03.12.20 00:22, Wei Liu wrote:
> 
> Hi,
> 
> > I don't follow. Do you mean reusing /dev/kvm but with a different set of
> > APIs underneath? I don't think that will work.
> 
> My idea was using the same uapi for both hypervisors, so that we can use
> the same userlands for both.
> 
> Are the semantis so different that we can't provide the same API ?

We can provide some similar APIs for ease of porting, but can't provide
1:1 mappings. By definition KVM and MSHV are two different things. There
is no goal to make one ABI / API compatible with the other.

> 
> > In any case, the first version of /dev/mshv was posted a few days ago
> > [0].  While we've chosen to follow closely KVM's model, Microsoft
> > Hypervisor has its own APIs.
> 
> I have to admit, I don't know much about hyperv - what are the main
> differences (from userland perspective) between hyperv and kvm ?
> 

They have different architecture and hence different ways to deal with
things. The difference will inevitably make its way to userland.

Without going into all the details, you can have a look how Xen and KVM
differ architecturally. That will give you a pretty good idea on the
differences.

Wei.

> 
> --mtx
> 
> -- 
> ---
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> Enrico Weigelt, metux IT consult
> Free software and Linux embedded engineering
> info@metux.net -- +49-151-27565287

  reply	other threads:[~2020-12-15 16:44 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-24 17:07 [PATCH v3 00/17] Introducing Linux root partition support for Microsoft Hypervisor Wei Liu
2020-11-24 17:07 ` [PATCH v3 01/17] asm-generic/hyperv: change HV_CPU_POWER_MANAGEMENT to HV_CPU_MANAGEMENT Wei Liu
2021-01-06 15:45   ` Wei Liu
2020-11-24 17:07 ` [PATCH v3 02/17] x86/hyperv: detect if Linux is the root partition Wei Liu
2020-11-24 17:07 ` [PATCH v3 03/17] Drivers: hv: vmbus: skip VMBus initialization if Linux is root Wei Liu
2020-11-24 17:07 ` [PATCH v3 04/17] iommu/hyperv: don't setup IRQ remapping when running as root Wei Liu
2020-11-24 17:07 ` [PATCH v3 05/17] clocksource/hyperv: use MSR-based access if " Wei Liu
2020-11-24 17:07 ` [PATCH v3 06/17] x86/hyperv: allocate output arg pages if required Wei Liu
2020-11-24 17:07 ` [PATCH v3 07/17] x86/hyperv: extract partition ID from Microsoft Hypervisor if necessary Wei Liu
2020-11-24 17:07 ` [PATCH v3 08/17] x86/hyperv: handling hypercall page setup for root Wei Liu
2020-11-24 17:07 ` [PATCH v3 09/17] x86/hyperv: provide a bunch of helper functions Wei Liu
2020-11-24 17:07 ` [PATCH v3 10/17] x86/hyperv: implement and use hv_smp_prepare_cpus Wei Liu
2020-11-24 17:07 ` [PATCH v3 11/17] asm-generic/hyperv: update hv_msi_entry Wei Liu
2020-11-24 17:07 ` [PATCH v3 12/17] asm-generic/hyperv: update hv_interrupt_entry Wei Liu
2020-11-24 18:05   ` David Woodhouse
2020-12-02 13:39     ` Wei Liu
2020-11-24 17:07 ` [PATCH v3 13/17] asm-generic/hyperv: introduce hv_device_id and auxiliary structures Wei Liu
2020-11-24 17:07 ` [PATCH v3 14/17] asm-generic/hyperv: import data structures for mapping device interrupts Wei Liu
2020-11-24 17:07 ` [PATCH v3 15/17] x86/hyperv: implement an MSI domain for root partition Wei Liu
2020-11-24 20:10   ` kernel test robot
2020-11-25  4:01   ` kernel test robot
2020-11-24 17:07 ` [PATCH v3 16/17] x86/ioapic: export a few functions and data structures via io_apic.h Wei Liu
2020-11-25 10:26   ` Andy Shevchenko
2020-12-02 14:11     ` Wei Liu
2020-12-02 15:18       ` Andy Shevchenko
2020-11-24 17:07 ` [PATCH v3 17/17] x86/hyperv: handle IO-APIC when running as root Wei Liu
2020-11-25  5:16   ` kernel test robot
2020-12-02 19:51 ` [PATCH v3 00/17] Introducing Linux root partition support for Microsoft Hypervisor Enrico Weigelt, metux IT consult
2020-12-02 23:22   ` Wei Liu
2020-12-15 15:25     ` Enrico Weigelt, metux IT consult
2020-12-15 16:42       ` Wei Liu [this message]
2021-02-02 10:40         ` David Woodhouse
2021-02-02 12:16           ` Wei Liu

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