KVM: Miscellaneous updates

KVM: Miscellaneous updates

[Avi Kivity]

In today's episode:
- two old patches that were accidentally dropped (by me)
- a fix for CONFIG_PREEMPT
- an mmu fix to ignore the cache control bits provided by the guest
- a MAINTAINERS entry to point the finger at the perpetrators

-- 
error compiling committee.c: too many arguments to function

[PATCH 1/5] KVM: Make the GET_SREGS and SET_SREGS ioctls symmetric

[Avi Kivity]

This makes the SET_SREGS ioctl behave symmetrically to the GET_SREGS
ioctl wrt the segment access rights flag.

From: Uri Lublin <uril@qumranet.com>

Signed-off-by: Uri Lublin <uril@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

Index: linux-2.6/drivers/kvm/vmx.c
===================================================================
--- linux-2.6.orig/drivers/kvm/vmx.c
+++ linux-2.6/drivers/kvm/vmx.c
@@ -884,6 +884,8 @@ static void vmx_set_segment(struct kvm_v
 		ar |= (var->db & 1) << 14;
 		ar |= (var->g & 1) << 15;
 	}
+	if (ar == 0) /* a 0 value means unusable */
+		ar = AR_UNUSABLE_MASK;
 	vmcs_write32(sf->ar_bytes, ar);
 }
 

[PATCH 2/5] KVM: Move find_vmx_entry() to vmx.c

[Avi Kivity]

Signed-off-by: Avi Kivity <avi@qumranet.com>

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
@@ -72,17 +72,6 @@ static struct dentry *debugfs_dir;
 #define CR8_RESEVED_BITS (~0x0fULL)
 #define EFER_RESERVED_BITS 0xfffffffffffff2fe
 
-struct vmx_msr_entry *find_msr_entry(struct kvm_vcpu *vcpu, u32 msr)
-{
-	int i;
-
-	for (i = 0; i < vcpu->nmsrs; ++i)
-		if (vcpu->guest_msrs[i].index == msr)
-			return &vcpu->guest_msrs[i];
-	return 0;
-}
-EXPORT_SYMBOL_GPL(find_msr_entry);
-
 #ifdef CONFIG_X86_64
 // LDT or TSS descriptor in the GDT. 16 bytes.
 struct segment_descriptor_64 {
@@ -1124,8 +1113,6 @@ static int get_msr(struct kvm_vcpu *vcpu
 
 void set_efer(struct kvm_vcpu *vcpu, u64 efer)
 {
-	struct vmx_msr_entry *msr;
-
 	if (efer & EFER_RESERVED_BITS) {
 		printk(KERN_DEBUG "set_efer: 0x%llx #GP, reserved bits\n",
 		       efer);
@@ -1140,16 +1127,12 @@ void set_efer(struct kvm_vcpu *vcpu, u64
 		return;
 	}
 
+	kvm_arch_ops->set_efer(vcpu, efer);
+
 	efer &= ~EFER_LMA;
 	efer |= vcpu->shadow_efer & EFER_LMA;
 
 	vcpu->shadow_efer = efer;
-
-	msr = find_msr_entry(vcpu, MSR_EFER);
-
-	if (!(efer & EFER_LMA))
-	    efer &= ~EFER_LME;
-	msr->data = efer;
 }
 EXPORT_SYMBOL_GPL(set_efer);
 
Index: linux-2.6/drivers/kvm/vmx.c
===================================================================
--- linux-2.6.orig/drivers/kvm/vmx.c
+++ linux-2.6/drivers/kvm/vmx.c
@@ -78,8 +78,6 @@ static const u32 vmx_msr_index[] = {
 };
 #define NR_VMX_MSR (sizeof(vmx_msr_index) / sizeof(*vmx_msr_index))
 
-struct vmx_msr_entry *find_msr_entry(struct kvm_vcpu *vcpu, u32 msr);
-
 static inline int is_page_fault(u32 intr_info)
 {
 	return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VECTOR_MASK |
@@ -93,6 +91,16 @@ static inline int is_external_interrupt(
 		== (INTR_TYPE_EXT_INTR | INTR_INFO_VALID_MASK);
 }
 
+static struct vmx_msr_entry *find_msr_entry(struct kvm_vcpu *vcpu, u32 msr)
+{
+	int i;
+
+	for (i = 0; i < vcpu->nmsrs; ++i)
+		if (vcpu->guest_msrs[i].index == msr)
+			return &vcpu->guest_msrs[i];
+	return 0;
+}
+
 static void vmcs_clear(struct vmcs *vmcs)
 {
 	u64 phys_addr = __pa(vmcs);

[PATCH 3/5] KVM: Remove extranous put_cpu() from vcpu_put()

[Avi Kivity]

The arch splitting patchset left an extra put_cpu() in core code, where
it can cause trouble for CONFIG_PREEMPT kernels.

Reported by: Huihong Luo <huisinro@yahoo.com>

Signed-off-by: Avi Kivity <avi@qumranet.com>

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
@@ -205,7 +205,6 @@ static struct kvm_vcpu *vcpu_load(struct
 static void vcpu_put(struct kvm_vcpu *vcpu)
 {
 	kvm_arch_ops->vcpu_put(vcpu);
-	put_cpu();
 	mutex_unlock(&vcpu->mutex);
 }
 

[PATCH 4/5] KVM: MMU: Ignore pcd, pwt, and pat bits on ptes

[Avi Kivity]

The pcd, pwt, and pat bits on page table entries affect the cpu cache.  Since
the cache is a host resource, the guest should not be able to control it.
Moreover, the meaning of these bits changes depending on whether pat is
enabled or not.

So, force these bits to zero on shadow page table entries at all times.

Signed-off-by: Avi Kivity <avi@qumranet.com>

Index: linux-2.6/drivers/kvm/mmu.c
===================================================================
--- linux-2.6.orig/drivers/kvm/mmu.c
+++ linux-2.6/drivers/kvm/mmu.c
@@ -61,22 +61,9 @@
 
 
 #define PT32_PTE_COPY_MASK \
-	(PT_PRESENT_MASK | PT_PWT_MASK | PT_PCD_MASK | \
-	PT_ACCESSED_MASK | PT_DIRTY_MASK | PT_PAT_MASK | \
-	PT_GLOBAL_MASK )
-
-#define PT32_NON_PTE_COPY_MASK \
-	(PT_PRESENT_MASK | PT_PWT_MASK | PT_PCD_MASK | \
-	PT_ACCESSED_MASK | PT_DIRTY_MASK)
-
-
-#define PT64_PTE_COPY_MASK \
-	(PT64_NX_MASK | PT32_PTE_COPY_MASK)
-
-#define PT64_NON_PTE_COPY_MASK \
-	(PT64_NX_MASK | PT32_NON_PTE_COPY_MASK)
-
+	(PT_PRESENT_MASK | PT_ACCESSED_MASK | PT_DIRTY_MASK | PT_GLOBAL_MASK)
 
+#define PT64_PTE_COPY_MASK (PT64_NX_MASK | PT32_PTE_COPY_MASK)
 
 #define PT_FIRST_AVAIL_BITS_SHIFT 9
 #define PT64_SECOND_AVAIL_BITS_SHIFT 52
Index: linux-2.6/drivers/kvm/paging_tmpl.h
===================================================================
--- linux-2.6.orig/drivers/kvm/paging_tmpl.h
+++ linux-2.6/drivers/kvm/paging_tmpl.h
@@ -32,7 +32,6 @@
 	#define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)
 	#define PT_LEVEL_MASK(level) PT64_LEVEL_MASK(level)
 	#define PT_PTE_COPY_MASK PT64_PTE_COPY_MASK
-	#define PT_NON_PTE_COPY_MASK PT64_NON_PTE_COPY_MASK
 #elif PTTYPE == 32
 	#define pt_element_t u32
 	#define guest_walker guest_walker32
@@ -43,7 +42,6 @@
 	#define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)
 	#define PT_LEVEL_MASK(level) PT32_LEVEL_MASK(level)
 	#define PT_PTE_COPY_MASK PT32_PTE_COPY_MASK
-	#define PT_NON_PTE_COPY_MASK PT32_NON_PTE_COPY_MASK
 #else
 	#error Invalid PTTYPE value
 #endif
@@ -105,9 +103,7 @@ static void FNAME(set_pde)(struct kvm_vc
 	if (PTTYPE == 32 && is_cpuid_PSE36())
 		gaddr |= (guest_pde & PT32_DIR_PSE36_MASK) <<
 			(32 - PT32_DIR_PSE36_SHIFT);
-	*shadow_pte = (guest_pde & (PT_NON_PTE_COPY_MASK | PT_GLOBAL_MASK)) |
-		          ((guest_pde & PT_DIR_PAT_MASK) >>
-			            (PT_DIR_PAT_SHIFT - PT_PAT_SHIFT));
+	*shadow_pte = guest_pde & PT_PTE_COPY_MASK;
 	set_pte_common(vcpu, shadow_pte, gaddr,
 		       guest_pde & PT_DIRTY_MASK, access_bits);
 }
@@ -162,6 +158,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu
 		u32 index = SHADOW_PT_INDEX(addr, level);
 		u64 *shadow_ent = ((u64 *)__va(shadow_addr)) + index;
 		pt_element_t *guest_ent;
+		u64 shadow_pte;
 
 		if (is_present_pte(*shadow_ent) || is_io_pte(*shadow_ent)) {
 			if (level == PT_PAGE_TABLE_LEVEL)
@@ -204,14 +201,11 @@ static u64 *FNAME(fetch)(struct kvm_vcpu
 		shadow_addr = kvm_mmu_alloc_page(vcpu, shadow_ent);
 		if (!VALID_PAGE(shadow_addr))
 			return ERR_PTR(-ENOMEM);
-		if (!kvm_arch_ops->is_long_mode(vcpu) && level == 3)
-			*shadow_ent = shadow_addr |
-				(*guest_ent & (PT_PRESENT_MASK | PT_PWT_MASK | PT_PCD_MASK));
-		else {
-			*shadow_ent = shadow_addr |
-				(*guest_ent & PT_NON_PTE_COPY_MASK);
-			*shadow_ent |= (PT_WRITABLE_MASK | PT_USER_MASK);
-		}
+		shadow_pte = shadow_addr | PT_PRESENT_MASK;
+		if (vcpu->mmu.root_level > 3 || level != 3)
+			shadow_pte |= PT_ACCESSED_MASK
+				| PT_WRITABLE_MASK | PT_USER_MASK;
+		*shadow_ent = shadow_pte;
 		prev_shadow_ent = shadow_ent;
 	}
 }

[PATCH 5/5] KVM: Add MAINTAINERS entry

[Avi Kivity]

Signed-off-by: Avi Kivity <avi@qumranet.com>

Index: linux-2.6/MAINTAINERS
===================================================================
--- linux-2.6.orig/MAINTAINERS
+++ linux-2.6/MAINTAINERS
@@ -1745,6 +1745,13 @@ W:	http://nfs.sourceforge.net/
 W:	http://www.cse.unsw.edu.au/~neilb/patches/linux-devel/
 S:	Maintained
 
+KERNEL VIRTUAL MACHINE (KVM)
+P:	Avi Kivity
+M:	avi@qumranet.com
+L:	kvm-devel@lists.sourceforge.net
+W:	kvm.sourceforge.net
+S:	Supported
+
 KEXEC
 P:	Eric Biederman
 M:	ebiederm@xmission.com