From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756216AbYAFOkR (ORCPT ); Sun, 6 Jan 2008 09:40:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754438AbYAFOjm (ORCPT ); Sun, 6 Jan 2008 09:39:42 -0500 Received: from il.qumranet.com ([82.166.9.18]:46585 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753175AbYAFOjl (ORCPT ); Sun, 6 Jan 2008 09:39:41 -0500 From: Avi Kivity To: linux-kernel@vger.kernel.org, kvm-devel@lists.sourceforge.net Cc: Marcelo Tosatti Subject: [PATCH 02/33] KVM: MMU: emulated cmpxchg8b should be atomic on i386 Date: Sun, 6 Jan 2008 16:39:08 +0200 Message-Id: <1199630379-28638-3-git-send-email-avi@qumranet.com> X-Mailer: git-send-email 1.5.3.7 In-Reply-To: <1199630379-28638-1-git-send-email-avi@qumranet.com> References: <1199630379-28638-1-git-send-email-avi@qumranet.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Marcelo Tosatti Emulate cmpxchg8b atomically on i386. This is required to avoid a guest pte walker from seeing a splitted write. [avi: make it compile] Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity --- drivers/kvm/x86.c | 26 ++++++++++++++++++++++++++ 1 files changed, 26 insertions(+), 0 deletions(-) diff --git a/drivers/kvm/x86.c b/drivers/kvm/x86.c index 9db4e32..3b79684 100644 --- a/drivers/kvm/x86.c +++ b/drivers/kvm/x86.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include @@ -1674,6 +1675,31 @@ static int emulator_cmpxchg_emulated(unsigned long addr, reported = 1; printk(KERN_WARNING "kvm: emulating exchange as write\n"); } +#ifndef CONFIG_X86_64 + /* guests cmpxchg8b have to be emulated atomically */ + if (bytes == 8) { + gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, addr); + struct page *page; + char *addr; + u64 val; + + if (gpa == UNMAPPED_GVA || + (gpa & PAGE_MASK) == APIC_DEFAULT_PHYS_BASE) + goto emul_write; + + if (((gpa + bytes - 1) & PAGE_MASK) != (gpa & PAGE_MASK)) + goto emul_write; + + val = *(u64 *)new; + page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT); + addr = kmap_atomic(page, KM_USER0); + set_64bit((u64 *)(addr + offset_in_page(gpa)), val); + kunmap_atomic(addr, KM_USER0); + kvm_release_page_dirty(page); + } +emul_write: +#endif + return emulator_write_emulated(addr, new, bytes, vcpu); } -- 1.5.3.7