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From:   Vitaly Kuznetsov <vkuznets@redhat.com>
To:     x86@kernel.org
Cc:     "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        "Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>,
        devel@linuxdriverproject.org, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>, linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] x86/hyper-v: check cpumask_to_vpset() return value in hyperv_flush_tlb_others_ex()
Date:   Mon,  9 Jul 2018 19:40:11 +0200
Message-Id: <20180709174012.17429-2-vkuznets@redhat.com>
In-Reply-To: <20180709174012.17429-1-vkuznets@redhat.com>
References: <20180709174012.17429-1-vkuznets@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Commit 1268ed0c474a ("x86/hyper-v: Fix the circular dependency in IPI
enlightenment") made cpumask_to_vpset() return '-1' when there is a CPU
with unknown VP index in the supplied set. This needs to be checked before
we pass 'nr_bank' to hypercall.

Fixes: 1268ed0c474a ("x86/hyper-v: Fix the circular dependency in IPI enlightenment")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 arch/x86/hyperv/mmu.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c
index 0d90e515ec98..453d2355cd61 100644
--- a/arch/x86/hyperv/mmu.c
+++ b/arch/x86/hyperv/mmu.c
@@ -186,6 +186,8 @@ static u64 hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
 
 	flush->hv_vp_set.format = HV_GENERIC_SET_SPARSE_4K;
 	nr_bank = cpumask_to_vpset(&(flush->hv_vp_set), cpus);
+	if (nr_bank < 0)
+		return U64_MAX;
 
 	/*
 	 * We can flush not more than max_gvas with one hypercall. Flush the
-- 
2.14.4