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From: Wei Liu <wei.liu@kernel.org>
To: Vitaly Kuznetsov <vkuznets@redhat.com>
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>,
	Lillian Grassin-Drake <ligrassi@microsoft.com>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
	<x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH v2 08/17] x86/hyperv: handling hypercall page setup for root
Date: Fri, 13 Nov 2020 16:09:07 +0000	[thread overview]
Message-ID: <20201113160907.rwgpge3zo53fcgvo@liuwe-devbox-debian-v2> (raw)
In-Reply-To: <20201113153333.yt54enp5dbqjj5nu@liuwe-devbox-debian-v2>

On Fri, Nov 13, 2020 at 03:33:33PM +0000, Wei Liu wrote:
> On Thu, Nov 12, 2020 at 04:51:09PM +0100, Vitaly Kuznetsov wrote:
> > Wei Liu <wei.liu@kernel.org> writes:
> > 
> > > When Linux is running as the root partition, the hypercall page will
> > > have already been setup by Hyper-V. Copy the content over to the
> > > allocated page.
> > >
> > > The suspend, resume and cleanup paths remain untouched because they are
> > > not supported in this setup yet.
> > 
> > What about adding BUG_ONs there then?
> 
> I generally avoid cluttering code if I'm sure it definitely does not
> work.
> 
> In any case, adding BUG_ONs is not the right answer. Both hv_suspend and
> hv_resume can return an error code. I would rather just do
> 
>    if (hv_root_partition)
>        return -EPERM;
> 
> in both places.

Correction: hv_resume is void, so I won't add that code snippet. But we
should still be fine because hv_suspend will have already failed in the
first place.

Wei.

  reply	other threads:[~2020-11-13 16:09 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-05 16:57 [PATCH v2 00/17] Introducing Linux root partition support for Microsoft Hypervisor Wei Liu
2020-11-05 16:57 ` [PATCH v2 01/17] asm-generic/hyperv: change HV_CPU_POWER_MANAGEMENT to HV_CPU_MANAGEMENT Wei Liu
2020-11-12 15:14   ` Vitaly Kuznetsov
2020-11-05 16:57 ` [PATCH v2 02/17] x86/hyperv: detect if Linux is the root partition Wei Liu
2020-11-05 19:16   ` kernel test robot
2020-11-12 11:42     ` Wei Liu
2020-11-12 11:46       ` Wei Liu
2020-11-12 12:22         ` Wei Liu
2020-11-05 20:23   ` kernel test robot
2020-11-12 15:16   ` Vitaly Kuznetsov
2020-11-12 15:51     ` Wei Liu
2020-11-05 16:58 ` [PATCH v2 03/17] Drivers: hv: vmbus: skip VMBus initialization if Linux is root Wei Liu
2020-11-12 15:24   ` Vitaly Kuznetsov
2020-11-13 14:51     ` Wei Liu
2020-11-05 16:58 ` [PATCH v2 04/17] iommu/hyperv: don't setup IRQ remapping when running as root Wei Liu
2020-11-12 15:27   ` Vitaly Kuznetsov
2020-11-13 14:53     ` Wei Liu
2020-11-05 16:58 ` [PATCH v2 05/17] clocksource/hyperv: use MSR-based access if " Wei Liu
2020-11-12  9:56   ` Daniel Lezcano
2020-11-12 11:24     ` Wei Liu
2020-11-12 11:40       ` Daniel Lezcano
2020-11-12 11:42         ` Wei Liu
2020-11-12 15:30   ` Vitaly Kuznetsov
2020-11-12 15:52     ` Wei Liu
2020-11-05 16:58 ` [PATCH v2 06/17] x86/hyperv: allocate output arg pages if required Wei Liu
2020-11-12 15:35   ` Vitaly Kuznetsov
2020-11-13 15:05     ` Wei Liu
2020-11-05 16:58 ` [PATCH v2 07/17] x86/hyperv: extract partition ID from Microsoft Hypervisor if necessary Wei Liu
2020-11-05 20:07   ` kernel test robot
2020-11-12 11:54     ` Wei Liu
2020-11-05 20:20   ` kernel test robot
2020-11-12 15:44   ` Vitaly Kuznetsov
2020-11-13 15:21     ` Wei Liu
2020-11-05 16:58 ` [PATCH v2 08/17] x86/hyperv: handling hypercall page setup for root Wei Liu
2020-11-12 15:51   ` Vitaly Kuznetsov
2020-11-13 15:33     ` Wei Liu
2020-11-13 16:09       ` Wei Liu [this message]
2020-11-13 16:16         ` Vitaly Kuznetsov
2020-11-05 16:58 ` [PATCH v2 09/17] x86/hyperv: provide a bunch of helper functions Wei Liu
2020-11-12 15:57   ` Vitaly Kuznetsov
2020-11-13 15:51     ` Wei Liu
2020-11-13 16:13       ` Vitaly Kuznetsov
2020-11-16 11:41         ` Wei Liu
2020-11-05 16:58 ` [PATCH v2 10/17] x86/hyperv: implement and use hv_smp_prepare_cpus Wei Liu
2020-11-12 16:44   ` Vitaly Kuznetsov
2020-11-13 15:56     ` Wei Liu
2020-11-05 16:58 ` [PATCH v2 11/17] asm-generic/hyperv: update hv_msi_entry Wei Liu
2020-11-05 16:58 ` [PATCH v2 12/17] asm-generic/hyperv: update hv_interrupt_entry Wei Liu
2020-11-05 16:58 ` [PATCH v2 13/17] asm-generic/hyperv: introduce hv_device_id and auxiliary structures Wei Liu
2020-11-05 16:58 ` [PATCH v2 14/17] asm-generic/hyperv: import data structures for mapping device interrupts Wei Liu
2020-11-05 16:58 ` [PATCH v2 15/17] x86/hyperv: implement an MSI domain for root partition Wei Liu
2020-11-12 13:50   ` Wei Liu
2020-11-05 16:58 ` [PATCH v2 16/17] x86/ioapic: export a few functions and data structures via io_apic.h Wei Liu
2020-11-12 11:39   ` Wei Liu
2020-11-05 16:58 ` [PATCH v2 17/17] x86/hyperv: handle IO-APIC when running as root Wei Liu
2020-11-12 16:56   ` Vitaly Kuznetsov
2020-11-13 16:01     ` Wei Liu
2020-11-13 16:04       ` Wei Liu

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