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From:   Fenghua Yu <fenghua.yu@intel.com>
To:     "Thomas Gleixner" <tglx@linutronix.de>,
        "Joerg Roedel" <joro@8bytes.org>, "Ingo Molnar" <mingo@redhat.com>,
        "Borislav Petkov" <bp@alien8.de>,
        "Peter Zijlstra" <peterz@infradead.org>,
        "H Peter Anvin" <hpa@zytor.com>,
        "David Woodhouse" <dwmw2@infradead.org>,
        "Lu Baolu" <baolu.lu@linux.intel.com>,
        "Felix Kuehling" <Felix.Kuehling@amd.com>,
        "Dave Hansen" <dave.hansen@intel.com>,
        "Tony Luck" <tony.luck@intel.com>,
        "Jean-Philippe Brucker" <jean-philippe@linaro.org>,
        "Christoph Hellwig" <hch@infradead.org>,
        "Ashok Raj" <ashok.raj@intel.com>,
        "Jacob Jun Pan" <jacob.jun.pan@intel.com>,
        "Dave Jiang" <dave.jiang@intel.com>,
        "Sohil Mehta" <sohil.mehta@intel.com>,
        "Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc:     "linux-kernel" <linux-kernel@vger.kernel.org>,
        "x86" <x86@kernel.org>, iommu@lists.linux-foundation.org,
        "amd-gfx" <amd-gfx@lists.freedesktop.org>,
        Fenghua Yu <fenghua.yu@intel.com>
Subject: [PATCH v6 08/12] fork: Clear PASID for new mm
Date:   Mon, 13 Jul 2020 16:48:03 -0700
Message-Id: <1594684087-61184-9-git-send-email-fenghua.yu@intel.com>
In-Reply-To: <1594684087-61184-1-git-send-email-fenghua.yu@intel.com>
References: <1594684087-61184-1-git-send-email-fenghua.yu@intel.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

When a new mm is created, its PASID should be cleared, i.e. the PASID is
initialized to its init state 0 on both ARM and X86.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
---
v2:
- Add this patch to initialize PASID value for a new mm.

 include/linux/mm_types.h | 2 ++
 kernel/fork.c            | 8 ++++++++
 2 files changed, 10 insertions(+)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index d61285cfe027..d60d2ec10881 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -22,6 +22,8 @@
 #endif
 #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))
 
+/* Initial PASID value is 0. */
+#define INIT_PASID	0
 
 struct address_space;
 struct mem_cgroup;
diff --git a/kernel/fork.c b/kernel/fork.c
index 142b23645d82..43b5f112604d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1007,6 +1007,13 @@ static void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
 #endif
 }
 
+static void mm_init_pasid(struct mm_struct *mm)
+{
+#ifdef CONFIG_IOMMU_SUPPORT
+	mm->pasid = INIT_PASID;
+#endif
+}
+
 static void mm_init_uprobes_state(struct mm_struct *mm)
 {
 #ifdef CONFIG_UPROBES
@@ -1035,6 +1042,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
 	mm_init_cpumask(mm);
 	mm_init_aio(mm);
 	mm_init_owner(mm, p);
+	mm_init_pasid(mm);
 	RCU_INIT_POINTER(mm->exe_file, NULL);
 	mmu_notifier_subscriptions_init(mm);
 	init_tlb_flush_pending(mm);
-- 
2.19.1