From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: [patch 2/5] KVM: add kvm_read_guest_atomic() Date: Thu, 20 Dec 2007 19:18:23 -0500 Message-ID: <20071221002024.266517978@redhat.com> References: <20071221001821.029994250@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel , mtosatti-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org To: Avi Kivity Return-path: Content-Disposition: inline; filename=mmu-atomicity 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 In preparation for a mmu spinlock, add kvm_read_guest_atomic() and use it in fetch() and prefetch_page(). Signed-off-by: Marcelo Tosatti Index: kvm.quilt/arch/x86/kvm/paging_tmpl.h =================================================================== --- kvm.quilt.orig/arch/x86/kvm/paging_tmpl.h +++ kvm.quilt/arch/x86/kvm/paging_tmpl.h @@ -318,10 +318,12 @@ static u64 *FNAME(fetch)(struct kvm_vcpu metaphysical, access, shadow_ent, &new_page); if (new_page && !metaphysical) { + int r; pt_element_t curr_pte; - kvm_read_guest(vcpu->kvm, walker->pte_gpa[level - 2], - &curr_pte, sizeof(curr_pte)); - if (curr_pte != walker->ptes[level - 2]) + r = kvm_read_guest_atomic(vcpu->kvm, + walker->pte_gpa[level - 2], + &curr_pte, sizeof(curr_pte)); + if (r || curr_pte != walker->ptes[level - 2]) return NULL; } shadow_addr = __pa(shadow_page->spt); @@ -431,9 +433,8 @@ static gpa_t FNAME(gva_to_gpa)(struct kv static void FNAME(prefetch_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) { - int i, offset = 0; - pt_element_t *gpt; - struct page *page; + int i, offset = 0, r = 0; + pt_element_t pt; if (sp->role.metaphysical || (PTTYPE == 32 && sp->role.level > PT_PAGE_TABLE_LEVEL)) { @@ -443,15 +444,18 @@ static void FNAME(prefetch_page)(struct if (PTTYPE == 32) offset = sp->role.quadrant << PT64_LEVEL_BITS; - page = gfn_to_page(vcpu->kvm, sp->gfn); - gpt = kmap_atomic(page, KM_USER0); - for (i = 0; i < PT64_ENT_PER_PAGE; ++i) - if (is_present_pte(gpt[offset + i])) + + for (i = 0; i < PT64_ENT_PER_PAGE; ++i) { + gpa_t pte_gpa = gfn_to_gpa(sp->gfn); + pte_gpa += (i+offset) * sizeof(pt_element_t); + + r = kvm_read_guest_atomic(vcpu->kvm, pte_gpa, &pt, + sizeof(pt_element_t)); + if (r || is_present_pte(pt)) sp->spt[i] = shadow_trap_nonpresent_pte; else sp->spt[i] = shadow_notrap_nonpresent_pte; - kunmap_atomic(gpt, KM_USER0); - kvm_release_page_clean(page); + } } #undef pt_element_t Index: kvm.quilt/include/linux/kvm_host.h =================================================================== --- kvm.quilt.orig/include/linux/kvm_host.h +++ kvm.quilt/include/linux/kvm_host.h @@ -167,6 +167,8 @@ void kvm_release_page_clean(struct page void kvm_release_page_dirty(struct page *page); int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset, int len); +int kvm_read_guest_atomic(struct kvm *kvm, gpa_t gpa, void *data, + unsigned long len); int kvm_read_guest(struct kvm *kvm, gpa_t gpa, void *data, unsigned long len); int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn, const void *data, int offset, int len); Index: kvm.quilt/virt/kvm/kvm_main.c =================================================================== --- kvm.quilt.orig/virt/kvm/kvm_main.c +++ kvm.quilt/virt/kvm/kvm_main.c @@ -541,6 +541,26 @@ int kvm_read_guest(struct kvm *kvm, gpa_ } EXPORT_SYMBOL_GPL(kvm_read_guest); +int kvm_read_guest_atomic(struct kvm *kvm, gpa_t gpa, void *data, + unsigned long len) +{ + int r; + unsigned long addr; + gfn_t gfn = gpa >> PAGE_SHIFT; + int offset = offset_in_page(gpa); + + addr = gfn_to_hva(kvm, gfn); + if (kvm_is_error_hva(addr)) + return -EFAULT; + pagefault_disable(); + r = __copy_from_user_inatomic(data, (void __user *)addr + offset, len); + pagefault_enable(); + if (r) + return -EFAULT; + return 0; +} +EXPORT_SYMBOL(kvm_read_guest_atomic); + int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn, const void *data, int offset, int len) { -- ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/