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From: Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
To: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Cc: akpm-3NddpPZAyC0@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: [PATCH 3/33] KVM: MMU: Load the pae pdptrs on cr3 change like the	processor does
Date: Thu, 04 Jan 2007 15:52:05 -0000	[thread overview]
Message-ID: <20070104155205.CF83C250048@il.qumranet.com> (raw)
In-Reply-To: <459D21DD.5090506-atKUWr5tajBWk0Htik3J/w@public.gmane.org>

In pae mode, a load of cr3 loads the four third-level page table entries
in addition to cr3 itself.

Signed-off-by: Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>

Index: linux-2.6/drivers/kvm/kvm_main.c
===================================================================
--- linux-2.6.orig/drivers/kvm/kvm_main.c
+++ linux-2.6/drivers/kvm/kvm_main.c
@@ -298,14 +298,17 @@ static void inject_gp(struct kvm_vcpu *v
 	kvm_arch_ops->inject_gp(vcpu, 0);
 }
 
-static int pdptrs_have_reserved_bits_set(struct kvm_vcpu *vcpu,
-					 unsigned long cr3)
+/*
+ * Load the pae pdptrs.  Return true is they are all valid.
+ */
+static int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3)
 {
 	gfn_t pdpt_gfn = cr3 >> PAGE_SHIFT;
-	unsigned offset = (cr3 & (PAGE_SIZE-1)) >> 5;
+	unsigned offset = ((cr3 & (PAGE_SIZE-1)) >> 5) << 2;
 	int i;
 	u64 pdpte;
 	u64 *pdpt;
+	int ret;
 	struct kvm_memory_slot *memslot;
 
 	spin_lock(&vcpu->kvm->lock);
@@ -313,16 +316,23 @@ static int pdptrs_have_reserved_bits_set
 	/* FIXME: !memslot - emulate? 0xff? */
 	pdpt = kmap_atomic(gfn_to_page(memslot, pdpt_gfn), KM_USER0);
 
+	ret = 1;
 	for (i = 0; i < 4; ++i) {
 		pdpte = pdpt[offset + i];
-		if ((pdpte & 1) && (pdpte & 0xfffffff0000001e6ull))
-			break;
+		if ((pdpte & 1) && (pdpte & 0xfffffff0000001e6ull)) {
+			ret = 0;
+			goto out;
+		}
 	}
 
+	for (i = 0; i < 4; ++i)
+		vcpu->pdptrs[i] = pdpt[offset + i];
+
+out:
 	kunmap_atomic(pdpt, KM_USER0);
 	spin_unlock(&vcpu->kvm->lock);
 
-	return i != 4;
+	return ret;
 }
 
 void set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
@@ -368,8 +378,7 @@ void set_cr0(struct kvm_vcpu *vcpu, unsi
 			}
 		} else
 #endif
-		if (is_pae(vcpu) &&
-			    pdptrs_have_reserved_bits_set(vcpu, vcpu->cr3)) {
+		if (is_pae(vcpu) && !load_pdptrs(vcpu, vcpu->cr3)) {
 			printk(KERN_DEBUG "set_cr0: #GP, pdptrs "
 			       "reserved bits\n");
 			inject_gp(vcpu);
@@ -411,7 +420,7 @@ void set_cr4(struct kvm_vcpu *vcpu, unsi
 			return;
 		}
 	} else if (is_paging(vcpu) && !is_pae(vcpu) && (cr4 & CR4_PAE_MASK)
-		   && pdptrs_have_reserved_bits_set(vcpu, vcpu->cr3)) {
+		   && !load_pdptrs(vcpu, vcpu->cr3)) {
 		printk(KERN_DEBUG "set_cr4: #GP, pdptrs reserved bits\n");
 		inject_gp(vcpu);
 	}
@@ -443,7 +452,7 @@ void set_cr3(struct kvm_vcpu *vcpu, unsi
 			return;
 		}
 		if (is_paging(vcpu) && is_pae(vcpu) &&
-		    pdptrs_have_reserved_bits_set(vcpu, cr3)) {
+		    !load_pdptrs(vcpu, cr3)) {
 			printk(KERN_DEBUG "set_cr3: #GP, pdptrs "
 			       "reserved bits\n");
 			inject_gp(vcpu);
Index: linux-2.6/drivers/kvm/kvm.h
===================================================================
--- linux-2.6.orig/drivers/kvm/kvm.h
+++ linux-2.6/drivers/kvm/kvm.h
@@ -185,6 +185,7 @@ struct kvm_vcpu {
 	unsigned long cr3;
 	unsigned long cr4;
 	unsigned long cr8;
+	u64 pdptrs[4]; /* pae */
 	u64 shadow_efer;
 	u64 apic_base;
 	int nmsrs;

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  parent reply	other threads:[~2007-01-04 15:52 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-04 15:48 [PATCH 0/33] KVM: MMU: Cache shadow page tables Avi Kivity
2007-01-04 15:50 ` [PATCH 1/33] KVM: MMU: Implement simple reverse mapping Avi Kivity
     [not found] ` <459D21DD.5090506-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-01-04 15:51   ` [PATCH 2/33] KVM: MMU: Teach the page table walker to track guest page table gfns Avi Kivity
2007-01-04 15:52   ` Avi Kivity [this message]
2007-01-04 15:53   ` [PATCH 4/33] KVM: MMU: Fold fetch_guest() into init_walker() Avi Kivity
2007-01-04 15:54   ` [PATCH 5/33] KVM: MU: Special treatment for shadow pae root pages Avi Kivity
2007-01-04 15:55   ` [PATCH 6/33] KVM: MMU: Use the guest pdptrs instead of mapping cr3 in pae mode Avi Kivity
2007-01-04 15:56   ` [PATCH 7/33] KVM: MMU: Make the shadow page tables also special-case pae Avi Kivity
2007-01-04 15:57   ` [PATCH 8/33] KVM: MMU: Make kvm_mmu_alloc_page() return a kvm_mmu_page pointer Avi Kivity
2007-01-04 15:58   ` [PATCH 9/33] KVM: MMU: Shadow page table caching Avi Kivity
2007-01-04 15:59   ` [PATCH 10/33] KVM: MMU: Write protect guest pages when a shadow is created for them Avi Kivity
2007-01-04 16:00   ` [PATCH 11/33] KVM: MMU: Let the walker extract the target page gfn from the pte Avi Kivity
2007-01-04 16:01   ` [PATCH 12/33] KVM: MMU: Support emulated writes into RAM Avi Kivity
2007-01-04 16:02   ` [PATCH 13/33] KVM: MMU: Zap shadow page table entries on writes to guest page tables Avi Kivity
2007-01-04 16:03   ` [PATCH 14/33] KVM: MMU: If emulating an instruction fails, try unprotecting the page Avi Kivity
2007-01-04 16:04   ` [PATCH 15/33] KVM: MMU: Implement child shadow unlinking Avi Kivity
2007-01-04 16:06   ` [PATCH 17/33] KVM: MMU: oom handling Avi Kivity
2007-01-04 16:07   ` [PATCH 18/33] KVM: MMU: Remove invlpg interception Avi Kivity
2007-01-04 16:08   ` [PATCH 19/33] KVM: MMU: Remove release_pt_page_64() Avi Kivity
2007-01-04 16:10   ` [PATCH 21/33] KVM: MMU: <ove is_empty_shadow_page() above kvm_mmu_free_page() Avi Kivity
2007-01-04 16:11   ` [PATCH 22/33] KVM: MMU: Ensure freed shadow pages are clean Avi Kivity
2007-01-04 16:13   ` [PATCH 24/33] KVM: MMU: Page table write flood protection Avi Kivity
2007-01-04 16:14   ` [PATCH 25/33] KVM: MMU: Never free a shadow page actively serving as a root Avi Kivity
2007-01-04 16:15   ` [PATCH 26/33] KVM: MMU: Fix cmpxchg8b emulation Avi Kivity
2007-01-04 16:16   ` [PATCH 27/33] KVM: MMU: Treat user-mode faults as a hint that a page is no longer a page table Avi Kivity
2007-01-04 16:17   ` [PATCH 28/33] KVM: MMU: Free pages on kvm destruction Avi Kivity
2007-01-04 16:18   ` [PATCH 29/33] KVM: MMU: Replace atomic allocations by preallocated objects Avi Kivity
2007-01-04 16:19   ` [PATCH 30/33] KVM: MMU: Detect oom conditions and propagate error to userspace Avi Kivity
2007-01-04 16:20   ` [PATCH 31/33] KVM: MMU: Flush guest tlb when reducing permissions on a pte Avi Kivity
2007-01-04 16:21   ` [PATCH 32/33] KVM: MMU: Destroy mmu while we still have a vcpu left Avi Kivity
2007-01-04 16:22   ` [PATCH 33/33] KVM: MMU: add audit code to check mappings, etc are correct Avi Kivity
2007-01-04 17:22   ` [PATCH 0/33] KVM: MMU: Cache shadow page tables Andrew Morton
     [not found]     ` <20070104092226.91fa2dfe.akpm-3NddpPZAyC0@public.gmane.org>
2007-01-04 17:41       ` Avi Kivity
     [not found]         ` <459D3C65.2090703-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-01-04 18:02           ` Ingo Molnar
2007-01-04 16:05 ` [PATCH 16/33] KVM: MMU: kvm_mmu_put_page() only removes one link to the page Avi Kivity
2007-01-04 16:09 ` [PATCH 20/33] KVM: MMU: Handle misaligned accesses to write protected guest page tables Avi Kivity
2007-01-04 16:12 ` [PATCH 23/33] KVM: MMU: If an empty shadow page is not empty, report more info Avi Kivity

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