KVM: MTRR: sort variable MTRRs

Sort all valid variable MTRRs based on its base address, it will help us to
check a range to see if it's fully contained in variable MTRRs

Signed-off-by: Xiao Guangrong <[email protected]>
[Fix list insertion sort, simplify var_mtrr_range_is_valid to just
 test the V bit. - Paolo]
Signed-off-by: Paolo Bonzini <[email protected]>

Author: Xiao Guangrong

arch/x86/include/asm/kvm_host.h

@@ -345,12 +345,15 @@ enum {
 struct kvm_mtrr_range {
 	u64 base;
 	u64 mask;
+	struct list_head node;
 };
 
 struct kvm_mtrr {
 	struct kvm_mtrr_range var_ranges[KVM_NR_VAR_MTRR];
 	mtrr_type fixed_ranges[KVM_NR_FIXED_MTRR_REGION];
 	u64 deftype;
+
+	struct list_head head;
 };
 
 struct kvm_vcpu_arch {

arch/x86/kvm/mtrr.c

@@ -285,6 +285,39 @@ static void update_mtrr(struct kvm_vcpu *vcpu, u32 msr)
 	kvm_zap_gfn_range(vcpu->kvm, gpa_to_gfn(start), gpa_to_gfn(end));
 }
 
+static bool var_mtrr_range_is_valid(struct kvm_mtrr_range *range)
+{
+	return (range->mask & (1 << 11)) != 0;
+}
+
+static void set_var_mtrr_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data)
+{
+	struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state;
+	struct kvm_mtrr_range *tmp, *cur;
+	int index, is_mtrr_mask;
+
+	index = (msr - 0x200) / 2;
+	is_mtrr_mask = msr - 0x200 - 2 * index;
+	cur = &mtrr_state->var_ranges[index];
+
+	/* remove the entry if it's in the list. */
+	if (var_mtrr_range_is_valid(cur))
+		list_del(&mtrr_state->var_ranges[index].node);
+
+	if (!is_mtrr_mask)
+		cur->base = data;
+	else
+		cur->mask = data;
+
+	/* add it to the list if it's enabled. */
+	if (var_mtrr_range_is_valid(cur)) {
+		list_for_each_entry(tmp, &mtrr_state->head, node)
+			if (cur->base >= tmp->base)
+				break;
+		list_add_tail(&cur->node, &tmp->node);
+	}
+}
+
 int kvm_mtrr_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data)
 {
 	int index;
@@ -299,16 +332,8 @@ int kvm_mtrr_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data)
 		vcpu->arch.mtrr_state.deftype = data;
 	else if (msr == MSR_IA32_CR_PAT)
 		vcpu->arch.pat = data;
-	else {	/* Variable MTRRs */
-		int is_mtrr_mask;
-
-		index = (msr - 0x200) / 2;
-		is_mtrr_mask = msr - 0x200 - 2 * index;
-		if (!is_mtrr_mask)
-			vcpu->arch.mtrr_state.var_ranges[index].base = data;
-		else
-			vcpu->arch.mtrr_state.var_ranges[index].mask = data;
-	}
+	else
+		set_var_mtrr_msr(vcpu, msr, data);
 
 	update_mtrr(vcpu, msr);
 	return 0;
@@ -354,6 +379,11 @@ int kvm_mtrr_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
 	return 0;
 }
 
+void kvm_vcpu_mtrr_init(struct kvm_vcpu *vcpu)
+{
+	INIT_LIST_HEAD(&vcpu->arch.mtrr_state.head);
+}
+
 u8 kvm_mtrr_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)
 {
 	struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state;

arch/x86/kvm/x86.c

@@ -7379,13 +7379,13 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
 {
 	int r;
 
+	kvm_vcpu_mtrr_init(vcpu);
 	r = vcpu_load(vcpu);
 	if (r)
 		return r;
 	kvm_vcpu_reset(vcpu, false);
 	kvm_mmu_setup(vcpu);
 	vcpu_put(vcpu);
-
 	return r;
 }
 

arch/x86/kvm/x86.h

@@ -162,6 +162,7 @@ int kvm_write_guest_virt_system(struct x86_emulate_ctxt *ctxt,
 	gva_t addr, void *val, unsigned int bytes,
 	struct x86_exception *exception);
 
+void kvm_vcpu_mtrr_init(struct kvm_vcpu *vcpu);
 u8 kvm_mtrr_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn);
 bool kvm_mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data);
 int kvm_mtrr_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data);