Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755599AbcJ1E1N (ORCPT ); Fri, 28 Oct 2016 00:27:13 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:38941 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S964971AbcJ1E0J (ORCPT ); Fri, 28 Oct 2016 00:26:09 -0400 From: Pan Xinhui To: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, virtualization@lists.linux-foundation.org, linux-s390@vger.kernel.org, xen-devel-request@lists.xenproject.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org Cc: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, mingo@redhat.com, peterz@infradead.org, paulmck@linux.vnet.ibm.com, will.deacon@arm.com, kernellwp@gmail.com, jgross@suse.com, pbonzini@redhat.com, bsingharora@gmail.com, boqun.feng@gmail.com, borntraeger@de.ibm.com, rkrcmar@redhat.com, David.Laight@ACULAB.COM, Pan Xinhui Subject: [PATCH v6 07/11] KVM: Introduce kvm_write_guest_offset_cached Date: Fri, 28 Oct 2016 04:11:23 -0400 X-Mailer: git-send-email 2.4.11 In-Reply-To: <1477642287-24104-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> References: <1477642287-24104-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16102804-1617-0000-0000-00000170C31D X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16102804-1618-0000-0000-00004702F390 Message-Id: <1477642287-24104-8-git-send-email-xinhui.pan@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-10-28_02:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1609300000 definitions=main-1610280076 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2753 Lines: 75 It allows us to update some status or field of one struct partially. We can also save one kvm_read_guest_cached if we just update one filed of the struct regardless of its current value. Signed-off-by: Pan Xinhui --- include/linux/kvm_host.h | 2 ++ virt/kvm/kvm_main.c | 20 ++++++++++++++------ 2 files changed, 16 insertions(+), 6 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 01c0b9c..6f00237 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -645,6 +645,8 @@ int kvm_write_guest(struct kvm *kvm, gpa_t gpa, const void *data, unsigned long len); int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, void *data, unsigned long len); +int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, + void *data, int offset, unsigned long len); int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc, gpa_t gpa, unsigned long len); int kvm_clear_guest_page(struct kvm *kvm, gfn_t gfn, int offset, int len); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 2907b7b..95308ee 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1972,30 +1972,38 @@ int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc, } EXPORT_SYMBOL_GPL(kvm_gfn_to_hva_cache_init); -int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, - void *data, unsigned long len) +int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, + void *data, int offset, unsigned long len) { struct kvm_memslots *slots = kvm_memslots(kvm); int r; + gpa_t gpa = ghc->gpa + offset; - BUG_ON(len > ghc->len); + BUG_ON(len + offset > ghc->len); if (slots->generation != ghc->generation) kvm_gfn_to_hva_cache_init(kvm, ghc, ghc->gpa, ghc->len); if (unlikely(!ghc->memslot)) - return kvm_write_guest(kvm, ghc->gpa, data, len); + return kvm_write_guest(kvm, gpa, data, len); if (kvm_is_error_hva(ghc->hva)) return -EFAULT; - r = __copy_to_user((void __user *)ghc->hva, data, len); + r = __copy_to_user((void __user *)ghc->hva + offset, data, len); if (r) return -EFAULT; - mark_page_dirty_in_slot(ghc->memslot, ghc->gpa >> PAGE_SHIFT); + mark_page_dirty_in_slot(ghc->memslot, gpa >> PAGE_SHIFT); return 0; } +EXPORT_SYMBOL_GPL(kvm_write_guest_offset_cached); + +int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, + void *data, unsigned long len) +{ + return kvm_write_guest_offset_cached(kvm, ghc, data, 0, len); +} EXPORT_SYMBOL_GPL(kvm_write_guest_cached); int kvm_read_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, -- 2.4.11