From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759384AbXLWPF2 (ORCPT ); Sun, 23 Dec 2007 10:05:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755452AbXLWOw0 (ORCPT ); Sun, 23 Dec 2007 09:52:26 -0500 Received: from il.qumranet.com ([82.166.9.18]:35897 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755128AbXLWOvr (ORCPT ); Sun, 23 Dec 2007 09:51:47 -0500 From: Avi Kivity To: linux-kernel@vger.kernel.org, kvm-devel@lists.sourceforge.net Cc: Izik Eidus Subject: [PATCH 46/50] KVM: MMU: Keep a reverse mapping of non-writable translations Date: Sun, 23 Dec 2007 16:51:31 +0200 Message-Id: <1198421495-31481-47-git-send-email-avi@qumranet.com> X-Mailer: git-send-email 1.5.3.7 In-Reply-To: <1198421495-31481-1-git-send-email-avi@qumranet.com> References: <1198421495-31481-1-git-send-email-avi@qumranet.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Izik Eidus The current kvm mmu only reverse maps writable translation. This is used to write-protect a page in case it becomes a pagetable. But with swapping support, we need a reverse mapping of read-only pages as well: when we evict a page, we need to remove any mapping to it, whether writable or not. Signed-off-by: Izik Eidus Signed-off-by: Avi Kivity --- drivers/kvm/mmu.c | 23 +++++++++++------------ 1 files changed, 11 insertions(+), 12 deletions(-) diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c index 14e54e3..bbf5eb4 100644 --- a/drivers/kvm/mmu.c +++ b/drivers/kvm/mmu.c @@ -211,8 +211,8 @@ static int is_io_pte(unsigned long pte) static int is_rmap_pte(u64 pte) { - return (pte & (PT_WRITABLE_MASK | PT_PRESENT_MASK)) - == (PT_WRITABLE_MASK | PT_PRESENT_MASK); + return pte != shadow_trap_nonpresent_pte + && pte != shadow_notrap_nonpresent_pte; } static void set_shadow_pte(u64 *sptep, u64 spte) @@ -488,7 +488,6 @@ static void rmap_write_protect(struct kvm *kvm, u64 gfn) { unsigned long *rmapp; u64 *spte; - u64 *prev_spte; gfn = unalias_gfn(kvm, gfn); rmapp = gfn_to_rmap(kvm, gfn); @@ -497,13 +496,11 @@ static void rmap_write_protect(struct kvm *kvm, u64 gfn) while (spte) { BUG_ON(!spte); BUG_ON(!(*spte & PT_PRESENT_MASK)); - BUG_ON(!(*spte & PT_WRITABLE_MASK)); rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte); - prev_spte = spte; - spte = rmap_next(kvm, rmapp, spte); - rmap_remove(kvm, prev_spte); - set_shadow_pte(prev_spte, *prev_spte & ~PT_WRITABLE_MASK); + if (is_writeble_pte(*spte)) + set_shadow_pte(spte, *spte & ~PT_WRITABLE_MASK); kvm_flush_remote_tlbs(kvm); + spte = rmap_next(kvm, rmapp, spte); } } @@ -908,14 +905,18 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, hpa_t p) table = __va(table_addr); if (level == 1) { + int was_rmapped; + pte = table[index]; + was_rmapped = is_rmap_pte(pte); if (is_shadow_present_pte(pte) && is_writeble_pte(pte)) return 0; mark_page_dirty(vcpu->kvm, v >> PAGE_SHIFT); page_header_update_slot(vcpu->kvm, table, v); table[index] = p | PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK; - rmap_add(vcpu, &table[index], v >> PAGE_SHIFT); + if (!was_rmapped) + rmap_add(vcpu, &table[index], v >> PAGE_SHIFT); return 0; } @@ -1424,10 +1425,8 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot) pt = page->spt; for (i = 0; i < PT64_ENT_PER_PAGE; ++i) /* avoid RMW */ - if (pt[i] & PT_WRITABLE_MASK) { - rmap_remove(kvm, &pt[i]); + if (pt[i] & PT_WRITABLE_MASK) pt[i] &= ~PT_WRITABLE_MASK; - } } } -- 1.5.3.7