Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   KY Srinivasan <kys@microsoft.com>
To:     KY Srinivasan <kys@microsoft.com>,
        "x86@kernel.org" <x86@kernel.org>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "devel@linuxdriverproject.org" <devel@linuxdriverproject.org>,
        "olaf@aepfle.de" <olaf@aepfle.de>,
        "apw@canonical.com" <apw@canonical.com>,
        "jasowang@redhat.com" <jasowang@redhat.com>,
        "tglx@linutronix.de" <tglx@linutronix.de>,
        "hpa@zytor.com" <hpa@zytor.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        "Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>,
        "vkuznets@redhat.com" <vkuznets@redhat.com>
Subject: RE: [PATCH 1/1] X86: Fix the circular dependency in IPI
 enlightenment.
Thread-Topic: [PATCH 1/1] X86: Fix the circular dependency in IPI
 enlightenment.
Thread-Index: AQHUEx54dNXJT7NbtU+3bGq/CTzHOqR+GBog
Date:   Tue, 3 Jul 2018 22:44:36 +0000
Message-ID: <BL0PR2101MB1107AC5048311B0AC1C6A852A0420@BL0PR2101MB1107.namprd21.prod.outlook.com>
References: <20180703223641.4171-1-kys@linuxonhyperv.com>
In-Reply-To: <20180703223641.4171-1-kys@linuxonhyperv.com>
Accept-Language: en-US
Content-Language: en-US
received-spf: None (protection.outlook.com: microsoft.com does not designate
 permitted sender hosts)
spamdiagnosticoutput: 1:99
spamdiagnosticmetadata: NSPM
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: df7599e7-7cb8-4219-50f1-08d5e1368e16
X-MS-Exchange-CrossTenant-originalarrivaltime: 03 Jul 2018 22:44:36.8992
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL0PR2101MB0962
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


> -----Original Message-----
> From: kys@linuxonhyperv.com <kys@linuxonhyperv.com>
> Sent: Tuesday, July 3, 2018 3:37 PM
> To: x86@kernel.org; gregkh@linuxfoundation.org; linux-
> kernel@vger.kernel.org; devel@linuxdriverproject.org; olaf@aepfle.de;
> apw@canonical.com; jasowang@redhat.com; tglx@linutronix.de;
> hpa@zytor.com; Stephen Hemminger <sthemmin@microsoft.com>; Michael
> Kelley (EOSG) <Michael.H.Kelley@microsoft.com>; vkuznets@redhat.com
> Cc: KY Srinivasan <kys@microsoft.com>
> Subject: [PATCH 1/1] X86: Fix the circular dependency in IPI enlightenmen=
t.
>=20
> From: "K. Y. Srinivasan" <kys@microsoft.com>
>=20
> The IPI hypercalls depend on being able to map the Linux notion of CPU ID
> to the hypervisor's notion of the CPU ID. The array hv_vp_index[] provide=
s
> this mapping. Code for populating this array depends on the IPI functiona=
lity.
> Break this circular dependency.
>=20
> Fixes: 68bb7bfb7985 ("X86/Hyper-V: Enable IPI enlightenments")

Please drop this patch; I have sent the wrong patch.

Regards,

K. Y
>=20
> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
> Tested-by: Michael Kelley <mikelley@microsoft.com>
> ---
>  arch/x86/hyperv/hv_apic.c       | 5 +++++
>  arch/x86/hyperv/hv_init.c       | 3 +++
>  arch/x86/include/asm/mshyperv.h | 2 ++
>  3 files changed, 10 insertions(+)
>=20
> diff --git a/arch/x86/hyperv/hv_apic.c b/arch/x86/hyperv/hv_apic.c
> index f68855499391..63d7c196739f 100644
> --- a/arch/x86/hyperv/hv_apic.c
> +++ b/arch/x86/hyperv/hv_apic.c
> @@ -114,6 +114,8 @@ static bool __send_ipi_mask_ex(const struct cpumask
> *mask, int vector)
>  		ipi_arg->vp_set.format =3D HV_GENERIC_SET_SPARSE_4K;
>  		nr_bank =3D cpumask_to_vpset(&(ipi_arg->vp_set), mask);
>  	}
> +	if (nr_bank =3D=3D -1)
> +		goto ipi_mask_ex_done;
>  	if (!nr_bank)
>  		ipi_arg->vp_set.format =3D HV_GENERIC_SET_ALL;
>=20
> @@ -158,6 +160,9 @@ static bool __send_ipi_mask(const struct cpumask
> *mask, int vector)
>=20
>  	for_each_cpu(cur_cpu, mask) {
>  		vcpu =3D hv_cpu_number_to_vp_number(cur_cpu);
> +		if (vcpu =3D=3D -1)
> +			goto ipi_mask_done;
> +
>  		/*
>  		 * This particular version of the IPI hypercall can
>  		 * only target upto 64 CPUs.
> diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
> index 595e44e8abaa..762ce164d733 100644
> --- a/arch/x86/hyperv/hv_init.c
> +++ b/arch/x86/hyperv/hv_init.c
> @@ -293,6 +293,9 @@ void __init hyperv_init(void)
>  	if (!hv_vp_index)
>  		return;
>=20
> +	for (i =3D 0; i < num_possible_cpus(); i++)
> +		hv_vp_index[i] =3D -1;
> +
>  	hv_vp_assist_page =3D kcalloc(num_possible_cpus(),
>  				    sizeof(*hv_vp_assist_page), GFP_KERNEL);
>  	if (!hv_vp_assist_page) {
> diff --git a/arch/x86/include/asm/mshyperv.h
> b/arch/x86/include/asm/mshyperv.h
> index 81e768b8d9eb..299de3dcc319 100644
> --- a/arch/x86/include/asm/mshyperv.h
> +++ b/arch/x86/include/asm/mshyperv.h
> @@ -285,6 +285,8 @@ static inline int cpumask_to_vpset(struct hv_vpset
> *vpset,
>  	 */
>  	for_each_cpu(cpu, cpus) {
>  		vcpu =3D hv_cpu_number_to_vp_number(cpu);
> +		if (vcpu =3D=3D -1)
> +			return -1;
>  		vcpu_bank =3D vcpu / 64;
>  		vcpu_offset =3D vcpu % 64;
>  		__set_bit(vcpu_offset, (unsigned long *)
> --
> 2.17.1