In preparation for a mmu spinlock, avoid schedules in mmu_set_spte() by using follow_page() instead of get_user_pages().
The fault handling work by get_user_pages() now happens outside the lock. Signed-off-by: Marcelo Tosatti <[EMAIL PROTECTED]> Index: kvm.quilt/arch/x86/kvm/mmu.c =================================================================== --- kvm.quilt.orig/arch/x86/kvm/mmu.c +++ kvm.quilt/arch/x86/kvm/mmu.c @@ -907,7 +907,9 @@ static void mmu_set_spte(struct kvm_vcpu if (!(pte_access & ACC_EXEC_MASK)) spte |= PT64_NX_MASK; - page = gfn_to_page(vcpu->kvm, gfn); + page = kvm_follow_page(vcpu->kvm, gfn); + if (!page) + return; spte |= PT_PRESENT_MASK; if (pte_access & ACC_USER_MASK) @@ -983,8 +985,11 @@ static int nonpaging_map(struct kvm_vcpu table = __va(table_addr); if (level == 1) { + struct page *page; + page = gfn_to_page(vcpu->kvm, gfn); mmu_set_spte(vcpu, &table[index], ACC_ALL, ACC_ALL, 0, write, 1, &pt_write, gfn); + kvm_release_page_clean(page); return pt_write || is_io_pte(table[index]); } Index: kvm.quilt/include/linux/kvm_host.h =================================================================== --- kvm.quilt.orig/include/linux/kvm_host.h +++ kvm.quilt/include/linux/kvm_host.h @@ -163,6 +163,7 @@ int kvm_arch_set_memory_region(struct kv int user_alloc); gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn); struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn); +struct page *kvm_follow_page(struct kvm *kvm, gfn_t gfn); void kvm_release_page_clean(struct page *page); void kvm_release_page_dirty(struct page *page); int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset, Index: kvm.quilt/virt/kvm/kvm_main.c =================================================================== --- kvm.quilt.orig/virt/kvm/kvm_main.c +++ kvm.quilt/virt/kvm/kvm_main.c @@ -453,6 +453,25 @@ static unsigned long gfn_to_hva(struct k return (slot->userspace_addr + (gfn - slot->base_gfn) * PAGE_SIZE); } +struct page *kvm_follow_page(struct kvm *kvm, gfn_t gfn) +{ + unsigned long addr; + struct vm_area_struct *vma; + + addr = gfn_to_hva(kvm, gfn); + /* MMIO access */ + if (kvm_is_error_hva(addr)) { + get_page(bad_page); + return bad_page; + } + + vma = find_vma(current->mm, addr); + if (!vma) + return NULL; + + return follow_page(vma, addr, FOLL_GET|FOLL_TOUCH); +} + /* * Requires current->mm->mmap_sem to be held */ 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 @@ -67,6 +67,7 @@ struct guest_walker { gfn_t table_gfn[PT_MAX_FULL_LEVELS]; pt_element_t ptes[PT_MAX_FULL_LEVELS]; gpa_t pte_gpa[PT_MAX_FULL_LEVELS]; + struct page *page; unsigned pt_access; unsigned pte_access; gfn_t gfn; @@ -203,14 +204,18 @@ walk: --walker->level; } + walker->page = gfn_to_page(vcpu->kvm, walker->gfn); + if (write_fault && !is_dirty_pte(pte)) { bool ret; mark_page_dirty(vcpu->kvm, table_gfn); ret = FNAME(cmpxchg_gpte)(vcpu->kvm, table_gfn, index, pte, pte|PT_DIRTY_MASK); - if (ret) + if (ret) { + kvm_release_page_clean(walker->page); goto walk; + } pte |= PT_DIRTY_MASK; mutex_lock(&vcpu->kvm->lock); kvm_mmu_pte_write(vcpu, pte_gpa, (u8 *)&pte, sizeof(pte)); @@ -323,8 +328,10 @@ static u64 *FNAME(fetch)(struct kvm_vcpu 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; + if (r || curr_pte != walker->ptes[level - 2]) { + shadow_ent = NULL; + goto out; + } } shadow_addr = __pa(shadow_page->spt); shadow_pte = shadow_addr | PT_PRESENT_MASK | PT_ACCESSED_MASK @@ -336,7 +343,8 @@ static u64 *FNAME(fetch)(struct kvm_vcpu user_fault, write_fault, walker->ptes[walker->level-1] & PT_DIRTY_MASK, ptwrite, walker->gfn); - +out: + kvm_release_page_clean(walker->page); return shadow_ent; } @@ -425,6 +433,7 @@ static gpa_t FNAME(gva_to_gpa)(struct kv if (r) { gpa = gfn_to_gpa(walker.gfn); gpa |= vaddr & ~PAGE_MASK; + kvm_release_page_clean(walker.page); } return gpa; -- ------------------------------------------------------------------------- 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/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel