Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756303Ab0GEAzL (ORCPT ); Sun, 4 Jul 2010 20:55:11 -0400 Received: from mga11.intel.com ([192.55.52.93]:10538 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754411Ab0GEAzJ (ORCPT ); Sun, 4 Jul 2010 20:55:09 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.53,537,1272870000"; d="scan'208";a="582878922" From: Sheng Yang Organization: Intel Opensource Technology Center To: Xiao Guangrong Subject: Re: [PATCH] KVM: VMX: fix tlb flush with invalid root Date: Mon, 5 Jul 2010 08:52:48 +0800 User-Agent: KMail/1.13.2 (Linux/2.6.32-22-generic; KDE/4.4.2; x86_64; ; ) Cc: kvm@vger.kernel.org, Avi Kivity , Marcelo Tosatti , LKML References: <4C2EEEA2.5090305@cn.fujitsu.com> In-Reply-To: <4C2EEEA2.5090305@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Message-Id: <201007050852.49001.sheng@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2891 Lines: 84 On Saturday 03 July 2010 16:02:42 Xiao Guangrong wrote: > Commit 341d9b535b6c simplify reload logic while entry guest mode, it > can avoid unnecessary sync-root if KVM_REQ_MMU_RELOAD and > KVM_REQ_MMU_SYNC both set. Which commit you are talking about? Can't find 341d9b535b6c... -- regards Yang, Sheng > > But, it cause a issue that when we handle 'KVM_REQ_TLB_FLUSH', the > root is invalid, it is triggered during my test: > > Kernel BUG at ffffffffa00212b8 [verbose debug info unavailable] > ...... > > [] ? fget_light+0x111/0x28e > [] sys_ioctl+0x47/0x6a > [] system_call_fastpath+0x16/0x1b > Code: f0 eb 21 f7 c2 00 00 00 04 74 22 48 8d 45 f0 48 c7 45 f0 00 00 00 00 > 48 c7 45 f8 00 00 00 00 b9 02 00 00 00 66 0f 38 80 08 77 02 <0f> 0b c9 c3 > 55 48 89 e5 0f 1f 44 00 00 ba 00 68 00 00 48 8b 8f RIP > [] vmx_flush_tlb+0xdf/0xe3 [kvm_intel] > RSP > > Fixed by directly return if the root is not ready. > > Signed-off-by: Xiao Guangrong > --- > arch/x86/include/asm/kvm_host.h | 2 ++ > arch/x86/kvm/mmu.c | 2 -- > arch/x86/kvm/vmx.c | 5 ++++- > 3 files changed, 6 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h > b/arch/x86/include/asm/kvm_host.h index 2bda624..8f522ec 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -40,6 +40,8 @@ > 0xFFFFFF0000000000ULL) > > #define INVALID_PAGE (~(hpa_t)0) > +#define VALID_PAGE(x) ((x) != INVALID_PAGE) > + > #define UNMAPPED_GVA (~(gpa_t)0) > > /* KVM Hugepage definitions for x86 */ > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c > index a0c5c31..399ddb0 100644 > --- a/arch/x86/kvm/mmu.c > +++ b/arch/x86/kvm/mmu.c > @@ -92,8 +92,6 @@ module_param(oos_shadow, bool, 0644); > #define PT_FIRST_AVAIL_BITS_SHIFT 9 > #define PT64_SECOND_AVAIL_BITS_SHIFT 52 > > -#define VALID_PAGE(x) ((x) != INVALID_PAGE) > - > #define PT64_LEVEL_BITS 9 > > #define PT64_LEVEL_SHIFT(level) \ > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 806ab12..ebaaeaf 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -1831,8 +1831,11 @@ static void exit_lmode(struct kvm_vcpu *vcpu) > static void vmx_flush_tlb(struct kvm_vcpu *vcpu) > { > vpid_sync_context(to_vmx(vcpu)); > - if (enable_ept) > + if (enable_ept) { > + if (!VALID_PAGE(vcpu->arch.mmu.root_hpa)) > + return; > ept_sync_context(construct_eptp(vcpu->arch.mmu.root_hpa)); > + } > } > > static void vmx_decache_cr0_guest_bits(struct kvm_vcpu *vcpu) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/