From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49033) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cxF8o-0006Wv-NK for qemu-devel@nongnu.org; Sun, 09 Apr 2017 11:52:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cxF8n-0006Eo-T4 for qemu-devel@nongnu.org; Sun, 09 Apr 2017 11:52:38 -0400 Received: from mail-ua0-x22a.google.com ([2607:f8b0:400c:c08::22a]:34100) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1cxF8n-0006Ei-OJ for qemu-devel@nongnu.org; Sun, 09 Apr 2017 11:52:37 -0400 Received: by mail-ua0-x22a.google.com with SMTP id u103so16154380uau.1 for ; Sun, 09 Apr 2017 08:52:35 -0700 (PDT) MIME-Version: 1.0 From: hrg Date: Sun, 9 Apr 2017 23:52:34 +0800 Message-ID: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [RFC/BUG] xen-mapcache: buggy invalidate map cache? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: stefano.stabellini@eu.citrix.com, anthony.perard@citrix.com, xen-devel@lists.xensource.com, qemu-devel@nongnu.org Cc: xen-devel@lists.xenproject.org, xen-devel@lists.xen.org, "Herongguang (Stephen)" , wangxinxin.wang@huawei.com Hi, In xen_map_cache_unlocked(), map to guest memory maybe in entry->next instead of first level entry (if map to rom other than guest memory comes first), while in xen_invalidate_map_cache(), when VM ballooned out memory, qemu did not invalidate cache entries in linked list(entry->next), so when VM balloon back in memory, gfns probably mapped to different mfns, thus if guest asks device to DMA to these GPA, qemu may DMA to stale MFNs. So I think in xen_invalidate_map_cache() linked lists should also be checked and invalidated. What=E2=80=99s your opinion? Is this a bug? Is my analyze correct? From mboxrd@z Thu Jan 1 00:00:00 1970 From: hrg Subject: [Qemu-devel] [RFC/BUG] xen-mapcache: buggy invalidate map cache? Date: Sun, 9 Apr 2017 23:52:34 +0800 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" To: stefano.stabellini@eu.citrix.com, anthony.perard@citrix.com, xen-devel@lists.xensource.com, qemu-devel@nongnu.org Cc: xen-devel@lists.xenproject.org, wangxinxin.wang@huawei.com, "Herongguang (Stephen)" , xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org SGksCgpJbiB4ZW5fbWFwX2NhY2hlX3VubG9ja2VkKCksIG1hcCB0byBndWVzdCBtZW1vcnkgbWF5 YmUgaW4gZW50cnktPm5leHQKaW5zdGVhZCBvZiBmaXJzdCBsZXZlbCBlbnRyeSAoaWYgbWFwIHRv IHJvbSBvdGhlciB0aGFuIGd1ZXN0IG1lbW9yeQpjb21lcyBmaXJzdCksIHdoaWxlIGluIHhlbl9p bnZhbGlkYXRlX21hcF9jYWNoZSgpLCB3aGVuIFZNIGJhbGxvb25lZApvdXQgbWVtb3J5LCBxZW11 IGRpZCBub3QgaW52YWxpZGF0ZSBjYWNoZSBlbnRyaWVzIGluIGxpbmtlZApsaXN0KGVudHJ5LT5u ZXh0KSwgc28gd2hlbiBWTSBiYWxsb29uIGJhY2sgaW4gbWVtb3J5LCBnZm5zIHByb2JhYmx5Cm1h cHBlZCB0byBkaWZmZXJlbnQgbWZucywgdGh1cyBpZiBndWVzdCBhc2tzIGRldmljZSB0byBETUEg dG8gdGhlc2UKR1BBLCBxZW11IG1heSBETUEgdG8gc3RhbGUgTUZOcy4KClNvIEkgdGhpbmsgaW4g eGVuX2ludmFsaWRhdGVfbWFwX2NhY2hlKCkgbGlua2VkIGxpc3RzIHNob3VsZCBhbHNvIGJlCmNo ZWNrZWQgYW5kIGludmFsaWRhdGVkLgoKV2hhdOKAmXMgeW91ciBvcGluaW9uPyBJcyB0aGlzIGEg YnVnPyBJcyBteSBhbmFseXplIGNvcnJlY3Q/CgpfX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fXwpYZW4tZGV2ZWwgbWFpbGluZyBsaXN0Clhlbi1kZXZlbEBsaXN0 cy54ZW4ub3JnCmh0dHBzOi8vbGlzdHMueGVuLm9yZy94ZW4tZGV2ZWwK