Everything related to the new quirks and memory type features:

* small improvements to the quirks API
 
 * extending one of the quirks from just AMD to Intel as well, because
 4.2 can show the same problem with problematic firmware on Intel too.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM fixes from Paolo Bonzini:
 "Everything related to the new quirks and memory type features:

   - small improvements to the quirks API

   - extending one of the quirks from just AMD to Intel as well, because
     4.2 can show the same problem with problematic firmware on Intel
     too"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86: rename quirk constants to KVM_X86_QUIRK_*
  KVM: vmx: obey KVM_QUIRK_CD_NW_CLEARED
  KVM: x86: introduce kvm_check_has_quirk
  KVM: MTRR: simplify kvm_mtrr_get_guest_memory_type
  KVM: MTRR: fix memory type handling if MTRR is completely disabled

arch/x86/include/uapi/asm/kvm.h

@@ -354,7 +354,7 @@ struct kvm_xcrs {
 struct kvm_sync_regs {
 };
 
-#define KVM_QUIRK_LINT0_REENABLED	(1 << 0)
-#define KVM_QUIRK_CD_NW_CLEARED		(1 << 1)
+#define KVM_X86_QUIRK_LINT0_REENABLED	(1 << 0)
+#define KVM_X86_QUIRK_CD_NW_CLEARED	(1 << 1)
 
 #endif /* _ASM_X86_KVM_H */

arch/x86/kvm/lapic.c

@@ -1595,7 +1595,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event)
 	for (i = 0; i < APIC_LVT_NUM; i++)
 		apic_set_reg(apic, APIC_LVTT + 0x10 * i, APIC_LVT_MASKED);
 	apic_update_lvtt(apic);
-	if (!(vcpu->kvm->arch.disabled_quirks & KVM_QUIRK_LINT0_REENABLED))
+	if (kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_LINT0_REENABLED))
 		apic_set_reg(apic, APIC_LVT0,
 			     SET_APIC_DELIVERY_MODE(0, APIC_MODE_EXTINT));
 	apic_manage_nmi_watchdog(apic, kvm_apic_get_reg(apic, APIC_LVT0));

arch/x86/kvm/mtrr.c

@@ -120,6 +120,16 @@ static u8 mtrr_default_type(struct kvm_mtrr *mtrr_state)
 	return mtrr_state->deftype & IA32_MTRR_DEF_TYPE_TYPE_MASK;
 }
 
+static u8 mtrr_disabled_type(void)
+{
+	/*
+	 * Intel SDM 11.11.2.2: all MTRRs are disabled when
+	 * IA32_MTRR_DEF_TYPE.E bit is cleared, and the UC
+	 * memory type is applied to all of physical memory.
+	 */
+	return MTRR_TYPE_UNCACHABLE;
+}
+
 /*
 * Three terms are used in the following code:
 * - segment, it indicates the address segments covered by fixed MTRRs.
@@ -434,6 +444,8 @@ struct mtrr_iter {
 
 	/* output fields. */
 	int mem_type;
+	/* mtrr is completely disabled? */
+	bool mtrr_disabled;
 	/* [start, end) is not fully covered in MTRRs? */
 	bool partial_map;
 
@@ -549,7 +561,7 @@ static void mtrr_lookup_var_next(struct mtrr_iter *iter)
 static void mtrr_lookup_start(struct mtrr_iter *iter)
 {
 	if (!mtrr_is_enabled(iter->mtrr_state)) {
-		iter->partial_map = true;
+		iter->mtrr_disabled = true;
 		return;
 	}
 
@@ -563,6 +575,7 @@ static void mtrr_lookup_init(struct mtrr_iter *iter,
 	iter->mtrr_state = mtrr_state;
 	iter->start = start;
 	iter->end = end;
+	iter->mtrr_disabled = false;
 	iter->partial_map = false;
 	iter->fixed = false;
 	iter->range = NULL;
@@ -656,15 +669,19 @@ u8 kvm_mtrr_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)
 		return MTRR_TYPE_WRBACK;
 	}
 
-	/* It is not covered by MTRRs. */
-	if (iter.partial_map) {
-		/*
-		 * We just check one page, partially covered by MTRRs is
-		 * impossible.
-		 */
-		WARN_ON(type != -1);
-		type = mtrr_default_type(mtrr_state);
-	}
+	if (iter.mtrr_disabled)
+		return mtrr_disabled_type();
+
+	/*
+	 * We just check one page, partially covered by MTRRs is
+	 * impossible.
+	 */
+	WARN_ON(iter.partial_map);
+
+	/* not contained in any MTRRs. */
+	if (type == -1)
+		return mtrr_default_type(mtrr_state);
+
 	return type;
 }
 EXPORT_SYMBOL_GPL(kvm_mtrr_get_guest_memory_type);
@@ -689,6 +706,9 @@ bool kvm_mtrr_check_gfn_range_consistency(struct kvm_vcpu *vcpu, gfn_t gfn,
 			return false;
 	}
 
+	if (iter.mtrr_disabled)
+		return true;
+
 	if (!iter.partial_map)
 		return true;
 

arch/x86/kvm/svm.c

@@ -1672,7 +1672,7 @@ static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 	 * does not do it - this results in some delay at
 	 * reboot
 	 */
-	if (!(vcpu->kvm->arch.disabled_quirks & KVM_QUIRK_CD_NW_CLEARED))
+	if (kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_CD_NW_CLEARED))
 		cr0 &= ~(X86_CR0_CD | X86_CR0_NW);
 	svm->vmcb->save.cr0 = cr0;
 	mark_dirty(svm->vmcb, VMCB_CR);

arch/x86/kvm/vmx.c

@@ -8650,7 +8650,10 @@ static u64 vmx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
 
 	if (kvm_read_cr0(vcpu) & X86_CR0_CD) {
 		ipat = VMX_EPT_IPAT_BIT;
-		cache = MTRR_TYPE_UNCACHABLE;
+		if (kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_CD_NW_CLEARED))
+			cache = MTRR_TYPE_WRBACK;
+		else
+			cache = MTRR_TYPE_UNCACHABLE;
 		goto exit;
 	}
 

arch/x86/kvm/x86.h

@@ -147,6 +147,11 @@ static inline void kvm_register_writel(struct kvm_vcpu *vcpu,
 	return kvm_register_write(vcpu, reg, val);
 }
 
+static inline bool kvm_check_has_quirk(struct kvm *kvm, u64 quirk)
+{
+	return !(kvm->arch.disabled_quirks & quirk);
+}
+
 void kvm_before_handle_nmi(struct kvm_vcpu *vcpu);
 void kvm_after_handle_nmi(struct kvm_vcpu *vcpu);
 void kvm_set_pending_timer(struct kvm_vcpu *vcpu);