linux-kernel - [PATCH] virt: acrn: obtain pa from VMA with PFNMAP flag

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Message-Id: <20220228022212.419406-1-yonghua.huang@intel.com>
Date:   Mon, 28 Feb 2022 05:22:12 +0300
From:   Yonghua Huang <yonghua.huang@...el.com>
To:     gregkh@...uxfoundation.org
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        reinette.chatre@...el.com, zhi.a.wang@...el.com,
        yu1.wang@...el.com, fei1.Li@...el.com,
        Yonghua Huang <yonghua.huang@...el.com>,
        Fei Li <fei1.li@...el.com>
Subject: [PATCH] virt: acrn: obtain pa from VMA with PFNMAP flag

 acrn_vm_ram_map can't pin the user pages with VM_PFNMAP flag
 by calling get_user_pages_fast(), the PA(physical pages)
 may be mapped by kernel driver and set PFNMAP flag.

 This patch fixes logic to setup EPT mapping for PFN mapped RAM region
 by checking the memory attribute before adding EPT mapping for them.

Fixes: 88f537d5e8dd ("virt: acrn: Introduce EPT mapping management")
Signed-off-by: Yonghua Huang <yonghua.huang@...el.com>
Signed-off-by: Fei Li <fei1.li@...el.com>
---
 drivers/virt/acrn/mm.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/virt/acrn/mm.c b/drivers/virt/acrn/mm.c
index c4f2e15c8a2b..3b1b1e7a844b 100644
--- a/drivers/virt/acrn/mm.c
+++ b/drivers/virt/acrn/mm.c
@@ -162,10 +162,34 @@ int acrn_vm_ram_map(struct acrn_vm *vm, struct acrn_vm_memmap *memmap)
 	void *remap_vaddr;
 	int ret, pinned;
 	u64 user_vm_pa;
+	unsigned long pfn;
+	struct vm_area_struct *vma;
 
 	if (!vm || !memmap)
 		return -EINVAL;
 
+	mmap_read_lock(current->mm);
+	vma = vma_lookup(current->mm, memmap->vma_base);
+	if (vma && ((vma->vm_flags & VM_PFNMAP) != 0)) {
+		if ((memmap->vma_base + memmap->len) > vma->vm_end) {
+			mmap_read_unlock(current->mm);
+			return -EINVAL;
+		}
+
+		ret = follow_pfn(vma, memmap->vma_base, &pfn);
+		mmap_read_unlock(current->mm);
+		if (ret < 0) {
+			dev_dbg(acrn_dev.this_device,
+				"Failed to lookup PFN at VMA:%pK.\n", (void *)memmap->vma_base);
+			return ret;
+		}
+
+		return acrn_mm_region_add(vm, memmap->user_vm_pa,
+			 PFN_PHYS(pfn), memmap->len,
+			 ACRN_MEM_TYPE_WB, memmap->attr);
+	}
+	mmap_read_unlock(current->mm);
+
 	/* Get the page number of the map region */
 	nr_pages = memmap->len >> PAGE_SHIFT;
 	pages = vzalloc(nr_pages * sizeof(struct page *));

base-commit: 73878e5eb1bd3c9656685ca60bc3a49d17311e0c
-- 
2.25.1