From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: [PATCH 5/7] KVM: Remove extraneous guest entry on mmio read Date: Sun, 29 Apr 2007 18:50:20 +0300 Message-ID: <11778618221425-git-send-email-avi@qumranet.com> References: <1177861822889-git-send-email-avi@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Return-path: In-Reply-To: <1177861822889-git-send-email-avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org When emulating an mmio read, we actually emulate twice: once to determine the physical address of the mmio, and, after we've exited to userspace to get the mmio value, we emulate again to place the value in the result register and update any flags. But we don't really need to enter the guest again for that, only to take an immediate vmexit. So, if we detect that we're doing an mmio read, emulate a single instruction before entering the guest again. Signed-off-by: Avi Kivity --- drivers/kvm/kvm.h | 1 + drivers/kvm/kvm_main.c | 5 ++++- 2 files changed, 5 insertions(+), 1 deletions(-) diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h index f99e89e..41634fd 100644 --- a/drivers/kvm/kvm.h +++ b/drivers/kvm/kvm.h @@ -310,6 +310,7 @@ struct kvm_vcpu { int mmio_size; unsigned char mmio_data[8]; gpa_t mmio_phys_addr; + gva_t mmio_fault_cr2; struct kvm_pio_request pio; void *pio_data; diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c index cdf0b17..a9ba42f 100644 --- a/drivers/kvm/kvm_main.c +++ b/drivers/kvm/kvm_main.c @@ -1186,6 +1186,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu, int r; int cs_db, cs_l; + vcpu->mmio_fault_cr2 = cr2; kvm_arch_ops->cache_regs(vcpu); kvm_arch_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l); @@ -1804,9 +1805,11 @@ static int kvm_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) r = complete_pio(vcpu); if (r) goto out; - } else { + } else if (!vcpu->mmio_is_write) { memcpy(vcpu->mmio_data, kvm_run->mmio.data, 8); vcpu->mmio_read_completed = 1; + emulate_instruction(vcpu, kvm_run, + vcpu->mmio_fault_cr2, 0); } } -- 1.5.0.6 ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/