RE: [PATCH v2 4/5] hv: Enable vmbus driver for nested root partition

From: "Michael Kelley (LINUX)" <mikelley@microsoft.com>
To: Jinank Jain <jinankjain@linux.microsoft.com>,
	Jinank Jain <jinankjain@microsoft.com>
Cc: KY Srinivasan <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	"sthemmin@microsoft.com" <sthemmin@microsoft.com>,
	"wei.liu@kernel.org" <wei.liu@kernel.org>,
	Dexuan Cui <decui@microsoft.com>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"bp@alien8.de" <bp@alien8.de>,
	"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
	"x86@kernel.org" <x86@kernel.org>,
	"hpa@zytor.com" <hpa@zytor.com>, "arnd@arndb.de" <arnd@arndb.de>,
	"peterz@infradead.org" <peterz@infradead.org>,
	"jpoimboe@kernel.org" <jpoimboe@kernel.org>,
	"seanjc@google.com" <seanjc@google.com>,
	"kirill.shutemov@linux.intel.com"
	<kirill.shutemov@linux.intel.com>,
	"ak@linux.intel.com" <ak@linux.intel.com>,
	"sathyanarayanan.kuppuswamy@linux.intel.com" 
	<sathyanarayanan.kuppuswamy@linux.intel.com>,
	"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>
Subject: RE: [PATCH v2 4/5] hv: Enable vmbus driver for nested root partition
Date: Thu, 3 Nov 2022 03:30:35 +0000	[thread overview]
Message-ID: <BYAPR21MB16880A610264D54C141B7D79D7389@BYAPR21MB1688.namprd21.prod.outlook.com> (raw)
In-Reply-To: <b5ea40f7e84e17a4338a313ab74292a293b1efa4.1667406350.git.jinankjain@linux.microsoft.com>

From: Jinank Jain <jinankjain@linux.microsoft.com> Sent: Wednesday, November 2, 2022 9:36 AM
> 
> Currently VMBus driver is not initialized for root partition but we need
> to enable the VMBus driver for nested root partition. This is required
> to expose VMBus devices to the L2 guest in the nested setup.
> 
> Signed-off-by: Jinank Jain <jinankjain@linux.microsoft.com>
> ---
>  drivers/hv/vmbus_drv.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 8b2e413bf19c..2f0cf75e811b 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -2723,7 +2723,7 @@ static int __init hv_acpi_init(void)
>  	if (!hv_is_hyperv_initialized())
>  		return -ENODEV;
> 
> -	if (hv_root_partition)
> +	if (hv_root_partition && !hv_nested)

Note that this code must compile and run when Linux is built
to run as a guest on Hyper-V for ARM64.  There's currently
no definition for hv_nested on the ARM64 side, so the compile
will fail.  But per my comments in Patch 1 in this series, using the
same technique as for hv_root_partition in hv_common.c should
solve the ARM64 problem as well.

>  		return 0;
> 
>  	/*
> --
> 2.25.1