Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760644Ab2EWRUQ (ORCPT ); Wed, 23 May 2012 13:20:16 -0400 Received: from e28smtp03.in.ibm.com ([122.248.162.3]:32910 "EHLO e28smtp03.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760592Ab2EWRUN (ORCPT ); Wed, 23 May 2012 13:20:13 -0400 Message-ID: <4FBCA5E5.4080402@linux.vnet.ibm.com> Date: Wed, 23 May 2012 16:55:01 +0800 From: Xiao Guangrong User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: Xiao Guangrong CC: Avi Kivity , Marcelo Tosatti , LKML , KVM Subject: [PATCH v5 5/9] KVM: MMU: introduce SPTE_MMU_WRITEABLE bit References: <4FBCA4FB.8050501@linux.vnet.ibm.com> In-Reply-To: <4FBCA4FB.8050501@linux.vnet.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit x-cbid: 12052317-3864-0000-0000-0000030677F4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4605 Lines: 149 This bit indicates whether the spte can be writable on MMU, that means the corresponding gpte is writable and the corresponding gfn is not protected by shadow page protection Signed-off-by: Xiao Guangrong --- arch/x86/kvm/mmu.c | 43 +++++++++++++++++++++++++++++-------------- 1 files changed, 29 insertions(+), 14 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 4810992..bd837f3 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -145,7 +145,8 @@ module_param(dbg, bool, 0644); #define CREATE_TRACE_POINTS #include "mmutrace.h" -#define SPTE_HOST_WRITEABLE (1ULL << PT_FIRST_AVAIL_BITS_SHIFT) +#define SPTE_HOST_WRITEABLE (1ULL << PT_FIRST_AVAIL_BITS_SHIFT) +#define SPTE_MMU_WRITEABLE (1ULL << (PT_FIRST_AVAIL_BITS_SHIFT + 1)) #define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level) @@ -1065,32 +1066,45 @@ static void drop_spte(struct kvm *kvm, u64 *sptep) rmap_remove(kvm, sptep); } +static bool spte_can_be_writable(u64 spte) +{ + u64 mask = SPTE_HOST_WRITEABLE | SPTE_MMU_WRITEABLE; + + return (spte & mask) == mask; +} + /* Return true if the spte is dropped. */ -static bool spte_write_protect(struct kvm *kvm, u64 *sptep, bool *flush) +static bool +spte_write_protect(struct kvm *kvm, u64 *sptep, bool *flush, bool pt_protect) { u64 spte = *sptep; - if (!is_writable_pte(spte)) + if (!is_writable_pte(spte) && + !(pt_protect && spte_can_be_writable(spte))) return false; rmap_printk("rmap_write_protect: spte %p %llx\n", sptep, *sptep); - *flush |= true; if (is_large_pte(spte)) { WARN_ON(page_header(__pa(sptep))->role.level == PT_PAGE_TABLE_LEVEL); + + *flush |= true; drop_spte(kvm, sptep); --kvm->stat.lpages; return true; } + if (pt_protect) + spte &= ~SPTE_MMU_WRITEABLE; spte = spte & ~PT_WRITABLE_MASK; - mmu_spte_update(sptep, spte); + + *flush = mmu_spte_update(sptep, spte); return false; } -static bool -__rmap_write_protect(struct kvm *kvm, unsigned long *rmapp, int level) +static bool __rmap_write_protect(struct kvm *kvm, unsigned long *rmapp, + int level, bool pt_protect) { u64 *sptep; struct rmap_iterator iter; @@ -1098,7 +1112,7 @@ __rmap_write_protect(struct kvm *kvm, unsigned long *rmapp, int level) for (sptep = rmap_get_first(*rmapp, &iter); sptep;) { BUG_ON(!(*sptep & PT_PRESENT_MASK)); - if (spte_write_protect(kvm, sptep, &flush)) { + if (spte_write_protect(kvm, sptep, &flush, pt_protect)) { sptep = rmap_get_first(*rmapp, &iter); continue; } @@ -1127,7 +1141,7 @@ void kvm_mmu_write_protect_pt_masked(struct kvm *kvm, while (mask) { rmapp = &slot->rmap[gfn_offset + __ffs(mask)]; - __rmap_write_protect(kvm, rmapp, PT_PAGE_TABLE_LEVEL); + __rmap_write_protect(kvm, rmapp, PT_PAGE_TABLE_LEVEL, false); /* clear the first set bit */ mask &= mask - 1; @@ -1146,7 +1160,7 @@ static bool rmap_write_protect(struct kvm *kvm, u64 gfn) for (i = PT_PAGE_TABLE_LEVEL; i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) { rmapp = __gfn_to_rmap(gfn, i, slot); - write_protected |= __rmap_write_protect(kvm, rmapp, i); + write_protected |= __rmap_write_protect(kvm, rmapp, i, true); } return write_protected; @@ -2284,8 +2298,10 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, spte |= shadow_x_mask; else spte |= shadow_nx_mask; + if (pte_access & ACC_USER_MASK) spte |= shadow_user_mask; + if (level > PT_PAGE_TABLE_LEVEL) spte |= PT_PAGE_SIZE_MASK; if (tdp_enabled) @@ -2310,7 +2326,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, goto done; } - spte |= PT_WRITABLE_MASK; + spte |= PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE; if (!vcpu->arch.mmu.direct_map && !(pte_access & ACC_WRITE_MASK)) { @@ -2339,8 +2355,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, __func__, gfn); ret = 1; pte_access &= ~ACC_WRITE_MASK; - if (is_writable_pte(spte)) - spte &= ~PT_WRITABLE_MASK; + spte &= ~(PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE); } } @@ -3921,7 +3936,7 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot) !is_last_spte(pt[i], sp->role.level)) continue; - spte_write_protect(kvm, &pt[i], &flush); + spte_write_protect(kvm, &pt[i], &flush, false); } } kvm_flush_remote_tlbs(kvm); -- 1.7.7.6 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/