From mboxrd@z Thu Jan 1 00:00:00 1970 From: Xiao Guangrong Subject: [PATCH v2 03/22] KVM: x86: fix broken read emulation spans a page boundary Date: Wed, 22 Jun 2011 22:29:13 +0800 Message-ID: <4E01FC39.2080709@cn.fujitsu.com> References: <4E01FBC9.3020009@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , LKML , KVM To: Avi Kivity Return-path: Received: from cn.fujitsu.com ([222.73.24.84]:53248 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1755582Ab1FVO1P (ORCPT ); Wed, 22 Jun 2011 10:27:15 -0400 In-Reply-To: <4E01FBC9.3020009@cn.fujitsu.com> Sender: kvm-owner@vger.kernel.org List-ID: If the range spans a boundary, the mmio access can be broke, fix it as write emulation. And we already get the guest physical address, so use it to read guest data directly to avoid walking guest page table again Signed-off-by: Xiao Guangrong --- arch/x86/kvm/x86.c | 41 ++++++++++++++++++++++++++++++++--------- 1 files changed, 32 insertions(+), 9 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0b803f0..eb27be4 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3944,14 +3944,13 @@ out: } EXPORT_SYMBOL_GPL(kvm_write_guest_virt_system); -static int emulator_read_emulated(struct x86_emulate_ctxt *ctxt, - unsigned long addr, - void *val, - unsigned int bytes, - struct x86_exception *exception) +static int emulator_read_emulated_onepage(unsigned long addr, + void *val, + unsigned int bytes, + struct x86_exception *exception, + struct kvm_vcpu *vcpu) { - struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt); - gpa_t gpa; + gpa_t gpa; int handled; if (vcpu->mmio_read_completed) { @@ -3971,8 +3970,7 @@ static int emulator_read_emulated(struct x86_emulate_ctxt *ctxt, if ((gpa & PAGE_MASK) == APIC_DEFAULT_PHYS_BASE) goto mmio; - if (kvm_read_guest_virt(ctxt, addr, val, bytes, exception) - == X86EMUL_CONTINUE) + if (!kvm_read_guest(vcpu->kvm, gpa, val, bytes)) return X86EMUL_CONTINUE; mmio: @@ -4001,6 +3999,31 @@ mmio: return X86EMUL_IO_NEEDED; } +static int emulator_read_emulated(struct x86_emulate_ctxt *ctxt, + unsigned long addr, + void *val, + unsigned int bytes, + struct x86_exception *exception) +{ + struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt); + + /* Crossing a page boundary? */ + if (((addr + bytes - 1) ^ addr) & PAGE_MASK) { + int rc, now; + + now = -addr & ~PAGE_MASK; + rc = emulator_read_emulated_onepage(addr, val, now, exception, + vcpu); + if (rc != X86EMUL_CONTINUE) + return rc; + addr += now; + val += now; + bytes -= now; + } + return emulator_read_emulated_onepage(addr, val, bytes, exception, + vcpu); +} + int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa, const void *val, int bytes) { -- 1.7.5.4