From patchwork Wed Mar 2 07:56:20 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kiszka X-Patchwork-Id: 85050 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [199.232.76.165]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id CDC58B70F6 for ; Wed, 2 Mar 2011 19:11:32 +1100 (EST) Received: from localhost ([127.0.0.1]:56346 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Puh9d-0002rR-QH for incoming@patchwork.ozlabs.org; Wed, 02 Mar 2011 03:11:29 -0500 Received: from [140.186.70.92] (port=41381 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PugvG-0005pD-HV for qemu-devel@nongnu.org; Wed, 02 Mar 2011 02:56:39 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PugvF-0005Gv-8P for qemu-devel@nongnu.org; Wed, 02 Mar 2011 02:56:38 -0500 Received: from thoth.sbs.de ([192.35.17.2]:34738) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PugvE-0005GM-V8 for qemu-devel@nongnu.org; Wed, 02 Mar 2011 02:56:37 -0500 Received: from mail1.siemens.de (localhost [127.0.0.1]) by thoth.sbs.de (8.13.6/8.13.6) with ESMTP id p227uYIc028434; Wed, 2 Mar 2011 08:56:34 +0100 Received: from mchn199C.mchp.siemens.de ([146.254.217.97]) by mail1.siemens.de (8.13.6/8.13.6) with ESMTP id p227uKnV031204; Wed, 2 Mar 2011 08:56:33 +0100 From: Jan Kiszka To: Avi Kivity , Marcelo Tosatti Date: Wed, 2 Mar 2011 08:56:20 +0100 Message-Id: X-Mailer: git-send-email 1.7.1 In-Reply-To: References: In-Reply-To: References: X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6, seldom 2.4 (older, 4) X-Received-From: 192.35.17.2 Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, Huang Ying Subject: [Qemu-devel] [PATCH v3 17/17] KVM, MCE, unpoison memory address across reboot X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Huang Ying In Linux kernel HWPoison processing implementation, the virtual address in processes mapping the error physical memory page is marked as HWPoison. So that, the further accessing to the virtual address will kill corresponding processes with SIGBUS. If the error physical memory page is used by a KVM guest, the SIGBUS will be sent to QEMU, and QEMU will simulate a MCE to report that memory error to the guest OS. If the guest OS can not recover from the error (for example, the page is accessed by kernel code), guest OS will reboot the system. But because the underlying host virtual address backing the guest physical memory is still poisoned, if the guest system accesses the corresponding guest physical memory even after rebooting, the SIGBUS will still be sent to QEMU and MCE will be simulated. That is, guest system can not recover via rebooting. In fact, across rebooting, the contents of guest physical memory page need not to be kept. We can allocate a new host physical page to back the corresponding guest physical address. This patch fixes this issue in QEMU-KVM via calling qemu_ram_remap() to clear the corresponding page table entry, so that make it possible to allocate a new page to recover the issue. [ Jan: rebasing and tiny cleanups] Signed-off-by: Huang Ying Signed-off-by: Jan Kiszka --- target-i386/kvm.c | 36 ++++++++++++++++++++++++++++++++++++ 1 files changed, 36 insertions(+), 0 deletions(-) diff --git a/target-i386/kvm.c b/target-i386/kvm.c index 44e5504..7b7105d 100644 --- a/target-i386/kvm.c +++ b/target-i386/kvm.c @@ -173,7 +173,40 @@ static int get_para_features(CPUState *env) } #endif /* CONFIG_KVM_PARA */ +typedef struct HWPoisonPage { + ram_addr_t ram_addr; + QLIST_ENTRY(HWPoisonPage) list; +} HWPoisonPage; + +static QLIST_HEAD(, HWPoisonPage) hwpoison_page_list = + QLIST_HEAD_INITIALIZER(hwpoison_page_list); + +static void kvm_unpoison_all(void *param) +{ + HWPoisonPage *page, *next_page; + + QLIST_FOREACH_SAFE(page, &hwpoison_page_list, list, next_page) { + QLIST_REMOVE(page, list); + qemu_ram_remap(page->ram_addr, TARGET_PAGE_SIZE); + qemu_free(page); + } +} + #ifdef KVM_CAP_MCE +static void kvm_hwpoison_page_add(ram_addr_t ram_addr) +{ + HWPoisonPage *page; + + QLIST_FOREACH(page, &hwpoison_page_list, list) { + if (page->ram_addr == ram_addr) { + return; + } + } + page = qemu_malloc(sizeof(HWPoisonPage)); + page->ram_addr = ram_addr; + QLIST_INSERT_HEAD(&hwpoison_page_list, page, list); +} + static int kvm_get_mce_cap_supported(KVMState *s, uint64_t *mce_cap, int *max_banks) { @@ -233,6 +266,7 @@ int kvm_arch_on_sigbus_vcpu(CPUState *env, int code, void *addr) hardware_memory_error(); } } + kvm_hwpoison_page_add(ram_addr); kvm_mce_inject(env, paddr, code); } else #endif /* KVM_CAP_MCE */ @@ -263,6 +297,7 @@ int kvm_arch_on_sigbus(int code, void *addr) "QEMU itself instead of guest system!: %p\n", addr); return 0; } + kvm_hwpoison_page_add(ram_addr); kvm_mce_inject(first_cpu, paddr, code); } else #endif /* KVM_CAP_MCE */ @@ -571,6 +606,7 @@ int kvm_arch_init(KVMState *s) fprintf(stderr, "e820_add_entry() table is full\n"); return ret; } + qemu_register_reset(kvm_unpoison_all, NULL); return 0; }