Merge tag 'kvm-3.11-2' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull more KVM changes from Gleb Natapov:
"A fix for a bug that prevents some guests from working on old Intel
CPUs and a patch that integrates ARM64 KVM, merged via ARM64 tree,
into Kconfig."

* tag 'kvm-3.11-2' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: VMX: mark unusable segment as nonpresent
arm64: KVM: Kconfig integration

arch/arm64/Kconfig

···
 
 source "fs/Kconfig"
 
+source "arch/arm64/kvm/Kconfig"
+
 source "arch/arm64/Kconfig.debug"
 
 source "security/Kconfig"

arch/arm64/kernel/asm-offsets.c

···
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/dma-mapping.h>
+#include <linux/kvm_host.h>
 #include <asm/thread_info.h>
 #include <asm/memory.h>
 #include <asm/cputable.h>

arch/arm64/kvm/Kconfig

···
+#
+# KVM configuration
+#
+
+source "virt/kvm/Kconfig"
+
+menuconfig VIRTUALIZATION
+	bool "Virtualization"
+	---help---
+	  Say Y here to get to see options for using your Linux host to run
+	  other operating systems inside virtual machines (guests).
+	  This option alone does not add any kernel code.
+
+	  If you say N, all options in this submenu will be skipped and
+	  disabled.
+
+if VIRTUALIZATION
+
+config KVM
+	bool "Kernel-based Virtual Machine (KVM) support"
+	select MMU_NOTIFIER
+	select PREEMPT_NOTIFIERS
+	select ANON_INODES
+	select KVM_MMIO
+	select KVM_ARM_HOST
+	select KVM_ARM_VGIC
+	select KVM_ARM_TIMER
+	---help---
+	  Support hosting virtualized guest machines.
+
+	  If unsure, say N.
+
+config KVM_ARM_HOST
+	bool
+	---help---
+	  Provides host support for ARM processors.
+
+config KVM_ARM_VGIC
+	bool
+	depends on KVM_ARM_HOST && OF
+	select HAVE_KVM_IRQCHIP
+	---help---
+	  Adds support for a hardware assisted, in-kernel GIC emulation.
+
+config KVM_ARM_TIMER
+	bool
+	depends on KVM_ARM_VGIC
+	---help---
+	  Adds support for the Architected Timers in virtual machines.
+
+endif # VIRTUALIZATION

arch/x86/kvm/vmx.c

···
 	var->limit = vmx_read_guest_seg_limit(vmx, seg);
 	var->selector = vmx_read_guest_seg_selector(vmx, seg);
 	ar = vmx_read_guest_seg_ar(vmx, seg);
+	var->unusable = (ar >> 16) & 1;
 	var->type = ar & 15;
 	var->s = (ar >> 4) & 1;
 	var->dpl = (ar >> 5) & 3;
-	var->present = (ar >> 7) & 1;
+	/*
+	 * Some userspaces do not preserve unusable property. Since usable
+	 * segment has to be present according to VMX spec we can use present
+	 * property to amend userspace bug by making unusable segment always
+	 * nonpresent. vmx_segment_access_rights() already marks nonpresent
+	 * segment as unusable.
+	 */
+	var->present = !var->unusable;
 	var->avl = (ar >> 12) & 1;
 	var->l = (ar >> 13) & 1;
 	var->db = (ar >> 14) & 1;
 	var->g = (ar >> 15) & 1;
-	var->unusable = (ar >> 16) & 1;
 }
 
 static u64 vmx_get_segment_base(struct kvm_vcpu *vcpu, int seg)