Sets up the required registers to run code in HYP-mode from the kernel.

By setting the HVBAR the kernel can execute code in Hyp-mode with
the MMU disabled. The HVBAR initially points to initialization code,
which initializes other Hyp-mode registers and enables the MMU
for Hyp-mode. Afterwards, the HVBAR is changed to point to KVM
Hyp vectors used to catch guest faults and to switch to Hyp mode
to perform a world-switch into a KVM guest.

Also provides memory mapping code to map required code pages, data structures,
and I/O regions  accessed in Hyp mode at the same virtual address as the host
kernel virtual addresses, but which conforms to the architectural requirements
for translations in Hyp mode. This interface is added in arch/arm/kvm/arm_mmu.c
and is comprised of:
 - create_hyp_mappings(from, to);
 - create_hyp_io_mappings(from, to, phys_addr);
 - free_hyp_pmds();

Note: The initialization mechanism currently relies on an SMC #0 call
to the secure monitor, which was merely a fast way of getting to the
hypervisor. We are working on supporting Hyp mode boot of the kernel
and control of Hyp mode through a local kernel mechanism.

Signed-off-by: Marc Zyngier <marc.zyng...@arm.com>
Signed-off-by: Christoffer Dall <c.d...@virtualopensystems.com>
---
 arch/arm/include/asm/kvm_arm.h              |  109 +++++++++++++
 arch/arm/include/asm/kvm_asm.h              |   25 +++
 arch/arm/include/asm/kvm_mmu.h              |   36 ++++
 arch/arm/include/asm/pgtable-3level-hwdef.h |    4 
 arch/arm/include/asm/pgtable-3level.h       |    4 
 arch/arm/include/asm/pgtable.h              |    1 
 arch/arm/kvm/arm.c                          |  224 +++++++++++++++++++++++++++
 arch/arm/kvm/exports.c                      |   16 ++
 arch/arm/kvm/init.S                         |  130 ++++++++++++++++
 arch/arm/kvm/interrupts.S                   |   48 ++++++
 arch/arm/kvm/mmu.c                          |  189 +++++++++++++++++++++++
 mm/memory.c                                 |    2 
 12 files changed, 788 insertions(+)
 create mode 100644 arch/arm/include/asm/kvm_mmu.h

diff --git a/arch/arm/include/asm/kvm_arm.h b/arch/arm/include/asm/kvm_arm.h
index 2f9d28e..6e46541 100644
--- a/arch/arm/include/asm/kvm_arm.h
+++ b/arch/arm/include/asm/kvm_arm.h
@@ -19,10 +19,119 @@
 #ifndef __ARM_KVM_ARM_H__
 #define __ARM_KVM_ARM_H__
 
+#include <asm/types.h>
+
 /* Supported Processor Types */
 #define CORTEX_A15     (0xC0F)
 
 /* Multiprocessor Affinity Register */
 #define MPIDR_CPUID    (0x3 << 0)
 
+/* Hyp Configuration Register (HCR) bits */
+#define HCR_TGE                (1 << 27)
+#define HCR_TVM                (1 << 26)
+#define HCR_TTLB       (1 << 25)
+#define HCR_TPU                (1 << 24)
+#define HCR_TPC                (1 << 23)
+#define HCR_TSW                (1 << 22)
+#define HCR_TAC                (1 << 21)
+#define HCR_TIDCP      (1 << 20)
+#define HCR_TSC                (1 << 19)
+#define HCR_TID3       (1 << 18)
+#define HCR_TID2       (1 << 17)
+#define HCR_TID1       (1 << 16)
+#define HCR_TID0       (1 << 15)
+#define HCR_TWE                (1 << 14)
+#define HCR_TWI                (1 << 13)
+#define HCR_DC         (1 << 12)
+#define HCR_BSU                (3 << 10)
+#define HCR_BSU_IS     (1 << 10)
+#define HCR_FB         (1 << 9)
+#define HCR_VA         (1 << 8)
+#define HCR_VI         (1 << 7)
+#define HCR_VF         (1 << 6)
+#define HCR_AMO                (1 << 5)
+#define HCR_IMO                (1 << 4)
+#define HCR_FMO                (1 << 3)
+#define HCR_PTW                (1 << 2)
+#define HCR_SWIO       (1 << 1)
+#define HCR_VM         1
+
+/*
+ * The bits we set in HCR:
+ * TAC:                Trap ACTLR
+ * TSC:                Trap SMC
+ * TSW:                Trap cache operations by set/way
+ * TWI:                Trap WFI
+ * TIDCP:      Trap L2CTLR/L2ECTLR
+ * BSU_IS:     Upgrade barriers to the inner shareable domain
+ * FB:         Force broadcast of all maintainance operations
+ * AMO:                Override CPSR.A and enable signaling with VA
+ * IMO:                Override CPSR.I and enable signaling with VI
+ * FMO:                Override CPSR.F and enable signaling with VF
+ * SWIO:       Turn set/way invalidates into set/way clean+invalidate
+ */
+#define HCR_GUEST_MASK (HCR_TSC | HCR_TSW | HCR_TWI | HCR_VM | HCR_BSU_IS | \
+                       HCR_FB | HCR_TAC | HCR_AMO | HCR_IMO | HCR_FMO | \
+                       HCR_SWIO | HCR_TIDCP)
+
+/* Hyp System Control Register (HSCTLR) bits */
+#define HSCTLR_TE      (1 << 30)
+#define HSCTLR_EE      (1 << 25)
+#define HSCTLR_FI      (1 << 21)
+#define HSCTLR_WXN     (1 << 19)
+#define HSCTLR_I       (1 << 12)
+#define HSCTLR_C       (1 << 2)
+#define HSCTLR_A       (1 << 1)
+#define HSCTLR_M       1
+#define HSCTLR_MASK    (HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I | \
+                        HSCTLR_WXN | HSCTLR_FI | HSCTLR_EE | HSCTLR_TE)
+
+/* TTBCR and HTCR Registers bits */
+#define TTBCR_EAE      (1 << 31)
+#define TTBCR_IMP      (1 << 30)
+#define TTBCR_SH1      (3 << 28)
+#define TTBCR_ORGN1    (3 << 26)
+#define TTBCR_IRGN1    (3 << 24)
+#define TTBCR_EPD1     (1 << 23)
+#define TTBCR_A1       (1 << 22)
+#define TTBCR_T1SZ     (3 << 16)
+#define TTBCR_SH0      (3 << 12)
+#define TTBCR_ORGN0    (3 << 10)
+#define TTBCR_IRGN0    (3 << 8)
+#define TTBCR_EPD0     (1 << 7)
+#define TTBCR_T0SZ     3
+#define HTCR_MASK      (TTBCR_T0SZ | TTBCR_IRGN0 | TTBCR_ORGN0 | TTBCR_SH0)
+
+/* Hyp Debug Configuration Register bits */
+#define HDCR_TDRA      (1 << 11)
+#define HDCR_TDOSA     (1 << 10)
+#define HDCR_TDA       (1 << 9)
+#define HDCR_TDE       (1 << 8)
+#define HDCR_HPME      (1 << 7)
+#define HDCR_TPM       (1 << 6)
+#define HDCR_TPMCR     (1 << 5)
+#define HDCR_HPMN_MASK (0x1F)
+
+/* Virtualization Translation Control Register (VTCR) bits */
+#define VTCR_SH0       (3 << 12)
+#define VTCR_ORGN0     (3 << 10)
+#define VTCR_IRGN0     (3 << 8)
+#define VTCR_SL0       (3 << 6)
+#define VTCR_S         (1 << 4)
+#define VTCR_T0SZ      3
+#define VTCR_MASK      (VTCR_SH0 | VTCR_ORGN0 | VTCR_IRGN0 | VTCR_SL0 | \
+                        VTCR_S | VTCR_T0SZ | VTCR_MASK)
+#define VTCR_HTCR_SH   (VTCR_SH0 | VTCR_ORGN0 | VTCR_IRGN0)
+#define VTCR_SL_L2     0               /* Starting-level: 2 */
+#define VTCR_SL_L1     (1 << 6)        /* Starting-level: 1 */
+#define VTCR_GUEST_SL  VTCR_SL_L1
+#define VTCR_GUEST_T0SZ        0
+#if VTCR_GUEST_SL == 0
+#define VTTBR_X                (14 - VTCR_GUEST_T0SZ)
+#else
+#define VTTBR_X                (5 - VTCR_GUEST_T0SZ)
+#endif
+
+
 #endif /* __ARM_KVM_ARM_H__ */
diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
index 44591f9..58d51e3 100644
--- a/arch/arm/include/asm/kvm_asm.h
+++ b/arch/arm/include/asm/kvm_asm.h
@@ -26,5 +26,30 @@
 #define ARM_EXCEPTION_DATA_ABORT  4
 #define ARM_EXCEPTION_IRQ        5
 #define ARM_EXCEPTION_FIQ        6
+#define ARM_EXCEPTION_HVC        7
+
+/*
+ * SMC Hypervisor API call number
+ */
+#define SMCHYP_HVBAR_W 0xfffffff0
+
+#ifndef __ASSEMBLY__
+struct kvm_vcpu;
+
+extern char __kvm_hyp_init[];
+extern char __kvm_hyp_init_end[];
+
+extern char __kvm_hyp_exit[];
+extern char __kvm_hyp_exit_end[];
+
+extern char __kvm_hyp_vector[];
+
+extern char __kvm_hyp_code_start[];
+extern char __kvm_hyp_code_end[];
+
+extern void __kvm_flush_vm_context(void);
+
+extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
+#endif
 
 #endif /* __ARM_KVM_ASM_H__ */
diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
new file mode 100644
index 0000000..8252921
--- /dev/null
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2012 - Virtual Open Systems and Columbia University
+ * Author: Christoffer Dall <c.d...@virtualopensystems.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#ifndef __ARM_KVM_MMU_H__
+#define __ARM_KVM_MMU_H__
+
+/*
+ * The architecture supports 40-bit IPA as input to the 2nd stage translations
+ * and PTRS_PER_PGD2 could therefore be 1024.
+ *
+ * To save a bit of memory and to avoid alignment issues we assume 39-bit IPA
+ * for now, but remember that the level-1 table must be aligned to its size.
+ */
+#define PTRS_PER_PGD2  512
+#define PGD2_ORDER     get_order(PTRS_PER_PGD2 * sizeof(pgd_t))
+
+int create_hyp_mappings(void *from, void *to);
+int create_hyp_io_mappings(void *from, void *to, phys_addr_t);
+void free_hyp_pmds(void);
+
+#endif /* __ARM_KVM_MMU_H__ */
diff --git a/arch/arm/include/asm/pgtable-3level-hwdef.h 
b/arch/arm/include/asm/pgtable-3level-hwdef.h
index a2d404e..18f5cef 100644
--- a/arch/arm/include/asm/pgtable-3level-hwdef.h
+++ b/arch/arm/include/asm/pgtable-3level-hwdef.h
@@ -32,6 +32,9 @@
 #define PMD_TYPE_SECT          (_AT(pmdval_t, 1) << 0)
 #define PMD_BIT4               (_AT(pmdval_t, 0))
 #define PMD_DOMAIN(x)          (_AT(pmdval_t, 0))
+#define PMD_APTABLE_SHIFT      (61)
+#define PMD_APTABLE            (_AT(pgdval_t, 3) << PGD_APTABLE_SHIFT)
+#define PMD_PXNTABLE           (_AT(pgdval_t, 1) << 59)
 
 /*
  *   - section
@@ -41,6 +44,7 @@
 #define PMD_SECT_S             (_AT(pmdval_t, 3) << 8)
 #define PMD_SECT_AF            (_AT(pmdval_t, 1) << 10)
 #define PMD_SECT_nG            (_AT(pmdval_t, 1) << 11)
+#define PMD_SECT_PXN           (_AT(pmdval_t, 1) << 53)
 #define PMD_SECT_XN            (_AT(pmdval_t, 1) << 54)
 #define PMD_SECT_AP_WRITE      (_AT(pmdval_t, 0))
 #define PMD_SECT_AP_READ       (_AT(pmdval_t, 0))
diff --git a/arch/arm/include/asm/pgtable-3level.h 
b/arch/arm/include/asm/pgtable-3level.h
index b249035..1169a8a 100644
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h
@@ -107,6 +107,10 @@
 #define pud_none(pud)          (!pud_val(pud))
 #define pud_bad(pud)           (!(pud_val(pud) & 2))
 #define pud_present(pud)       (pud_val(pud))
+#define pmd_table(pmd)         ((pmd_val(pmd) & PMD_TYPE_MASK) == \
+                                                PMD_TYPE_TABLE)
+#define pmd_sect(pmd)          ((pmd_val(pmd) & PMD_TYPE_MASK) == \
+                                                PMD_TYPE_SECT)
 
 #define pud_clear(pudp)                        \
        do {                            \
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index f66626d..bc83540 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -82,6 +82,7 @@ extern pgprot_t               pgprot_kernel;
 #define PAGE_READONLY_EXEC     _MOD_PROT(pgprot_user, L_PTE_USER | 
L_PTE_RDONLY)
 #define PAGE_KERNEL            _MOD_PROT(pgprot_kernel, L_PTE_XN)
 #define PAGE_KERNEL_EXEC       pgprot_kernel
+#define PAGE_HYP               _MOD_PROT(pgprot_kernel, L_PTE_USER)
 
 #define __PAGE_NONE            __pgprot(_L_PTE_DEFAULT | L_PTE_RDONLY | 
L_PTE_XN)
 #define __PAGE_SHARED          __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_XN)
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 1f30b0a..0b1c466 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -34,6 +34,11 @@
 #include <asm/ptrace.h>
 #include <asm/mman.h>
 #include <asm/cputype.h>
+#include <asm/idmap.h>
+#include <asm/tlbflush.h>
+#include <asm/kvm_arm.h>
+#include <asm/kvm_asm.h>
+#include <asm/kvm_mmu.h>
 
 #ifdef REQUIRES_SEC
 __asm__(".arch_extension       sec");
@@ -42,6 +47,9 @@ __asm__(".arch_extension      sec");
 __asm__(".arch_extension       virt");
 #endif
 
+static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);
+static DEFINE_PER_CPU(struct vfp_hard_struct *, kvm_host_vfp_state);
+
 int kvm_arch_hardware_enable(void *garbage)
 {
        return 0;
@@ -293,13 +301,229 @@ long kvm_arch_vm_ioctl(struct file *filp,
        return -EINVAL;
 }
 
+static void cpu_set_vector(void *vector)
+{
+       unsigned long vector_ptr;
+       unsigned long smc_hyp_nr;
+
+       vector_ptr = (unsigned long)vector;
+       smc_hyp_nr = SMCHYP_HVBAR_W;
+
+       /*
+        * Set the HVBAR
+        */
+       asm volatile (
+               "mov    r0, %[vector_ptr]\n\t"
+               "mov    r7, %[smc_hyp_nr]\n\t"
+               "smc    #0\n\t" : :
+               [vector_ptr] "r" (vector_ptr),
+               [smc_hyp_nr] "r" (smc_hyp_nr) :
+               "r0", "r7");
+}
+
+static void cpu_init_hyp_mode(void *vector)
+{
+       unsigned long pgd_ptr;
+       unsigned long hyp_stack_ptr;
+       unsigned long stack_page;
+
+       cpu_set_vector(vector);
+
+       pgd_ptr = virt_to_phys(hyp_pgd);
+       stack_page = __get_cpu_var(kvm_arm_hyp_stack_page);
+       hyp_stack_ptr = stack_page + PAGE_SIZE;
+
+       /*
+        * Call initialization code
+        */
+       asm volatile (
+               "mov    r0, %[pgd_ptr]\n\t"
+               "mov    r1, %[hyp_stack_ptr]\n\t"
+               "hvc    #0\n\t" : :
+               [pgd_ptr] "r" (pgd_ptr),
+               [hyp_stack_ptr] "r" (hyp_stack_ptr) :
+               "r0", "r1");
+}
+
+/**
+ * Inits Hyp-mode on all online CPUs
+ */
+static int init_hyp_mode(void)
+{
+       phys_addr_t init_phys_addr;
+       int cpu;
+       int err = 0;
+
+       /*
+        * Allocate stack pages for Hypervisor-mode
+        */
+       for_each_possible_cpu(cpu) {
+               unsigned long stack_page;
+
+               stack_page = __get_free_page(GFP_KERNEL);
+               if (!stack_page) {
+                       err = -ENOMEM;
+                       goto out_free_stack_pages;
+               }
+
+               per_cpu(kvm_arm_hyp_stack_page, cpu) = stack_page;
+       }
+
+       /*
+        * Execute the init code on each CPU.
+        *
+        * Note: The stack is not mapped yet, so don't do anything else than
+        * initializing the hypervisor mode on each CPU using a local stack
+        * space for temporary storage.
+        */
+       init_phys_addr = virt_to_phys(__kvm_hyp_init);
+       for_each_online_cpu(cpu) {
+               smp_call_function_single(cpu, cpu_init_hyp_mode,
+                                        (void *)(long)init_phys_addr, 1);
+       }
+
+       /*
+        * Unmap the identity mapping
+        */
+       hyp_idmap_teardown();
+
+       /*
+        * Map the Hyp-code called directly from the host
+        */
+       err = create_hyp_mappings(__kvm_hyp_code_start, __kvm_hyp_code_end);
+       if (err) {
+               kvm_err("Cannot map world-switch code\n");
+               goto out_free_mappings;
+       }
+
+       /*
+        * Map the Hyp stack pages
+        */
+       for_each_possible_cpu(cpu) {
+               char *stack_page = (char *)per_cpu(kvm_arm_hyp_stack_page, cpu);
+               err = create_hyp_mappings(stack_page, stack_page + PAGE_SIZE);
+
+               if (err) {
+                       kvm_err("Cannot map hyp stack\n");
+                       goto out_free_mappings;
+               }
+       }
+
+       /*
+        * Set the HVBAR to the virtual kernel address
+        */
+       for_each_online_cpu(cpu)
+               smp_call_function_single(cpu, cpu_set_vector,
+                                        __kvm_hyp_vector, 1);
+
+       /*
+        * Map the host VFP structures
+        */
+       for_each_possible_cpu(cpu) {
+               struct vfp_hard_struct *vfp;
+
+               vfp = kmalloc(sizeof(*vfp), GFP_KERNEL);
+               if (!vfp) {
+                       kvm_err("Not enough memory for vfp struct\n");
+                       goto out_free_vfp;
+               }
+
+               memset(vfp, 0, sizeof(*vfp));
+               per_cpu(kvm_host_vfp_state, cpu) = vfp;
+               err = create_hyp_mappings(vfp, vfp + 1);
+
+               if (err) {
+                       kvm_err("Cannot map host VFP state: %d\n", err);
+                       goto out_free_vfp;
+               }
+       }
+
+       return 0;
+out_free_vfp:
+       for_each_possible_cpu(cpu)
+               kfree(per_cpu(kvm_host_vfp_state, cpu));
+out_free_mappings:
+       free_hyp_pmds();
+out_free_stack_pages:
+       for_each_possible_cpu(cpu)
+               free_page(per_cpu(kvm_arm_hyp_stack_page, cpu));
+       return err;
+}
+
+/**
+ * Initialize Hyp-mode and memory mappings on all CPUs.
+ */
 int kvm_arch_init(void *opaque)
 {
+       int err;
+
+       if (kvm_target_cpu() < 0) {
+               kvm_err("Target CPU not supported!\n");
+               return -ENODEV;
+       }
+
+       err = init_hyp_mode();
+       if (err)
+               goto out_err;
+
+       return 0;
+out_err:
+       return err;
+}
+
+static void cpu_exit_hyp_mode(void *vector)
+{
+       cpu_set_vector(vector);
+
+       /*
+        * Disable Hyp-MMU for each cpu
+        */
+       asm volatile ("hvc      #0");
+}
+
+static int exit_hyp_mode(void)
+{
+       phys_addr_t exit_phys_addr;
+       int cpu;
+
+       /*
+        * TODO: flush Hyp TLB in case idmap code overlaps.
+        * Note that we should do this in the monitor code when switching the
+        * HVBAR, but this is going  away and should be rather done in the Hyp
+        * mode change of HVBAR.
+        */
+       hyp_idmap_setup();
+       exit_phys_addr = virt_to_phys(__kvm_hyp_exit);
+       BUG_ON(exit_phys_addr & 0x1f);
+
+       /*
+        * Execute the exit code on each CPU.
+        *
+        * Note: The stack is not mapped yet, so don't do anything else than
+        * initializing the hypervisor mode on each CPU using a local stack
+        * space for temporary storage.
+        */
+       for_each_online_cpu(cpu) {
+               smp_call_function_single(cpu, cpu_exit_hyp_mode,
+                                        (void *)(long)exit_phys_addr, 1);
+       }
+
        return 0;
 }
 
 void kvm_arch_exit(void)
 {
+       int cpu;
+
+       exit_hyp_mode();
+
+       free_hyp_pmds();
+       for_each_possible_cpu(cpu) {
+               kfree(per_cpu(kvm_host_vfp_state, cpu));
+               per_cpu(kvm_host_vfp_state, cpu) = NULL;
+               free_page(per_cpu(kvm_arm_hyp_stack_page, cpu));
+               per_cpu(kvm_arm_hyp_stack_page, cpu) = 0;
+       }
 }
 
 static int arm_init(void)
diff --git a/arch/arm/kvm/exports.c b/arch/arm/kvm/exports.c
index 3e38c95..8ebdf07 100644
--- a/arch/arm/kvm/exports.c
+++ b/arch/arm/kvm/exports.c
@@ -17,5 +17,21 @@
  */
 
 #include <linux/module.h>
+#include <asm/kvm_asm.h>
+
+EXPORT_SYMBOL_GPL(__kvm_hyp_init);
+EXPORT_SYMBOL_GPL(__kvm_hyp_init_end);
+
+EXPORT_SYMBOL_GPL(__kvm_hyp_exit);
+EXPORT_SYMBOL_GPL(__kvm_hyp_exit_end);
+
+EXPORT_SYMBOL_GPL(__kvm_hyp_vector);
+
+EXPORT_SYMBOL_GPL(__kvm_hyp_code_start);
+EXPORT_SYMBOL_GPL(__kvm_hyp_code_end);
+
+EXPORT_SYMBOL_GPL(__kvm_vcpu_run);
+
+EXPORT_SYMBOL_GPL(__kvm_flush_vm_context);
 
 EXPORT_SYMBOL_GPL(smp_send_reschedule);
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index 1dc8926..4db26cb 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -15,5 +15,135 @@
  * along with this program; if not, write to the Free Software
  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
+
+#include <linux/linkage.h>
+#include <asm/unified.h>
 #include <asm/asm-offsets.h>
 #include <asm/kvm_asm.h>
+#include <asm/kvm_arm.h>
+
+@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+@  Hypervisor initialization
+@    - should be called with:
+@        r0 = Hypervisor pgd pointer
+@        r1 = top of Hyp stack (kernel VA)
+@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+       .text
+       .arm
+        .pushsection    .hyp.idmap.text,"ax"
+       .align 12
+__kvm_hyp_init:
+       .globl __kvm_hyp_init
+
+       @ Hyp-mode exception vector
+       nop
+       nop
+       nop
+       nop
+       nop
+       b       __do_hyp_init
+       nop
+       nop
+
+__do_hyp_init:
+       @ Set the sp to end of this page and push data for later use
+       mov     sp, pc
+       bic     sp, sp, #0x0ff
+       bic     sp, sp, #0xf00
+       add     sp, sp, #0x1000
+       push    {r0, r1, r2, r12}
+
+       @ Set the HTTBR to point to the hypervisor PGD pointer passed to
+       @ function and set the upper bits equal to the kernel PGD.
+       mrrc    p15, 1, r1, r2, c2
+       mcrr    p15, 4, r0, r2, c2
+
+       @ Set the HTCR and VTCR to the same shareability and cacheability
+       @ settings as the non-secure TTBCR and with T0SZ == 0.
+       mrc     p15, 4, r0, c2, c0, 2   @ HTCR
+       ldr     r12, =HTCR_MASK
+       bic     r0, r0, r12
+       mrc     p15, 0, r1, c2, c0, 2   @ TTBCR
+       and     r1, r1, #(HTCR_MASK & ~TTBCR_T0SZ)
+       orr     r0, r0, r1
+       mcr     p15, 4, r0, c2, c0, 2   @ HTCR
+
+       mrc     p15, 4, r1, c2, c1, 2   @ VTCR
+       bic     r1, r1, #(VTCR_HTCR_SH | VTCR_SL0)
+       bic     r0, r0, #(~VTCR_HTCR_SH)
+       orr     r1, r0, r1
+       orr     r1, r1, #(VTCR_SL_L1 | VTCR_GUEST_T0SZ)
+       mcr     p15, 4, r1, c2, c1, 2   @ VTCR
+
+       @ Use the same memory attributes for hyp. accesses as the kernel
+       @ (copy MAIRx ro HMAIRx).
+       mrc     p15, 0, r0, c10, c2, 0
+       mcr     p15, 4, r0, c10, c2, 0
+       mrc     p15, 0, r0, c10, c2, 1
+       mcr     p15, 4, r0, c10, c2, 1
+
+       @ Set the HSCTLR to:
+       @  - ARM/THUMB exceptions: Kernel config (Thumb-2 kernel)
+       @  - Endianness: Kernel config
+       @  - Fast Interrupt Features: Kernel config
+       @  - Write permission implies XN: disabled
+       @  - Instruction cache: enabled
+       @  - Data/Unified cache: enabled
+       @  - Memory alignment checks: enabled
+       @  - MMU: enabled (this code must be run from an identity mapping)
+       mrc     p15, 4, r0, c1, c0, 0   @ HSCR
+       ldr     r12, =HSCTLR_MASK
+       bic     r0, r0, r12
+       mrc     p15, 0, r1, c1, c0, 0   @ SCTLR
+       ldr     r12, =(HSCTLR_EE | HSCTLR_FI)
+       and     r1, r1, r12
+ ARM(  ldr     r12, =(HSCTLR_M | HSCTLR_A | HSCTLR_I)                  )
+ THUMB(        ldr     r12, =(HSCTLR_M | HSCTLR_A | HSCTLR_I | HSCTLR_TE)      
)
+       orr     r1, r1, r12
+       orr     r0, r0, r1
+       isb
+       mcr     p15, 4, r0, c1, c0, 0   @ HSCR
+       isb
+
+       @ Set stack pointer and return to the kernel
+       pop     {r0, r1, r2, r12}
+       mov     sp, r1
+       eret
+
+       .ltorg
+
+       .align 12
+
+       __kvm_init_sp:
+       .globl __kvm_hyp_init_end
+__kvm_hyp_init_end:
+
+       .align 12
+__kvm_hyp_exit:
+       .globl __kvm_hyp_exit
+
+       @ Hyp-mode exception vector
+       nop
+       nop
+       nop
+       nop
+       nop
+       b       __do_hyp_exit
+       nop
+       nop
+
+__do_hyp_exit:
+       @ Clear the MMU and TE bits in the HSCR
+       mrc     p15, 4, sp, c1, c0, 0   @ HSCR
+       bic     sp, sp, #((1 << 30) | (1 << 0))
+
+       isb
+       mcr     p15, 4, sp, c1, c0, 0   @ HSCR
+       mcr     p15, 4, r0, c8, c7, 0   @ Flush Hyp TLB, r0 ignored
+       isb
+       eret
+
+       .globl __kvm_hyp_exit_end
+__kvm_hyp_exit_end:
+
+       .popsection
diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S
index 1dc8926..bf09801 100644
--- a/arch/arm/kvm/interrupts.S
+++ b/arch/arm/kvm/interrupts.S
@@ -15,5 +15,53 @@
  * along with this program; if not, write to the Free Software
  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
+
+#include <linux/linkage.h>
+#include <linux/const.h>
+#include <asm/unified.h>
+#include <asm/page.h>
 #include <asm/asm-offsets.h>
 #include <asm/kvm_asm.h>
+#include <asm/kvm_arm.h>
+
+       .text
+       .align  PAGE_SHIFT
+
+__kvm_hyp_code_start:
+       .globl __kvm_hyp_code_start
+
+@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+@  Flush TLBs and instruction caches of current CPU for all VMIDs
+@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+
+ENTRY(__kvm_flush_vm_context)
+       bx      lr
+ENDPROC(__kvm_flush_vm_context)
+
+@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+@  Hypervisor world-switch code
+@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+
+ENTRY(__kvm_vcpu_run)
+       bx      lr
+
+
+@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+@  Hypervisor exception vector and handlers
+@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+
+       .align 5
+__kvm_hyp_vector:
+       .globl __kvm_hyp_vector
+       nop
+
+/*
+ * The below lines makes sure the HYP mode code fits in a single page (the
+ * assembler will bark at you if it doesn't). Please keep them together. If
+ * you plan to restructure the code or increase its size over a page, you'll
+ * have to fix the code in init_hyp_mode().
+ */
+__kvm_hyp_code_end:
+       .globl  __kvm_hyp_code_end
+
+       .org    __kvm_hyp_code_start + PAGE_SIZE
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 10ed464..6a7dfd4 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -15,3 +15,192 @@
  * along with this program; if not, write to the Free Software
  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
+
+#include <linux/mman.h>
+#include <linux/kvm_host.h>
+#include <linux/io.h>
+#include <asm/idmap.h>
+#include <asm/pgalloc.h>
+#include <asm/kvm_arm.h>
+#include <asm/kvm_mmu.h>
+#include <asm/mach/map.h>
+
+static DEFINE_MUTEX(kvm_hyp_pgd_mutex);
+
+static void free_ptes(pmd_t *pmd, unsigned long addr)
+{
+       pte_t *pte;
+       unsigned int i;
+
+       for (i = 0; i < PTRS_PER_PMD; i++, addr += PMD_SIZE) {
+               if (!pmd_none(*pmd) && pmd_table(*pmd)) {
+                       pte = pte_offset_kernel(pmd, addr);
+                       pte_free_kernel(NULL, pte);
+               }
+               pmd++;
+       }
+}
+
+/**
+ * free_hyp_pmds - free a Hyp-mode level-2 tables and child level-3 tables
+ *
+ * Assumes this is a page table used strictly in Hyp-mode and therefore 
contains
+ * only mappings in the kernel memory area, which is above PAGE_OFFSET.
+ */
+void free_hyp_pmds(void)
+{
+       pgd_t *pgd;
+       pud_t *pud;
+       pmd_t *pmd;
+       unsigned long addr;
+
+       mutex_lock(&kvm_hyp_pgd_mutex);
+       for (addr = PAGE_OFFSET; addr != 0; addr += PGDIR_SIZE) {
+               pgd = hyp_pgd + pgd_index(addr);
+               pud = pud_offset(pgd, addr);
+
+               if (pud_none(*pud))
+                       continue;
+               BUG_ON(pud_bad(*pud));
+
+               pmd = pmd_offset(pud, addr);
+               free_ptes(pmd, addr);
+               pmd_free(NULL, pmd);
+               pud_clear(pud);
+       }
+       mutex_unlock(&kvm_hyp_pgd_mutex);
+}
+
+/*
+ * Create a HYP pte mapping.
+ *
+ * If pfn_base is NULL, we map kernel pages into HYP with the virtual
+ * address. Otherwise, this is considered an I/O mapping and we map
+ * the physical region starting at *pfn_base to [start, end[.
+ */
+static void create_hyp_pte_mappings(pmd_t *pmd, unsigned long start,
+                                   unsigned long end, unsigned long *pfn_base)
+{
+       pte_t *pte;
+       unsigned long addr;
+       pgprot_t prot;
+
+       if (pfn_base)
+               prot = __pgprot(get_mem_type_prot_pte(MT_DEVICE) | L_PTE_USER);
+       else
+               prot = PAGE_HYP;
+
+       for (addr = start & PAGE_MASK; addr < end; addr += PAGE_SIZE) {
+               pte = pte_offset_kernel(pmd, addr);
+               if (pfn_base) {
+                       BUG_ON(pfn_valid(*pfn_base));
+                       set_pte_ext(pte, pfn_pte(*pfn_base, prot), 0);
+                       (*pfn_base)++;
+               } else {
+                       struct page *page;
+                       BUG_ON(!virt_addr_valid(addr));
+                       page = virt_to_page(addr);
+                       set_pte_ext(pte, mk_pte(page, prot), 0);
+               }
+
+       }
+}
+
+static int create_hyp_pmd_mappings(pud_t *pud, unsigned long start,
+                                  unsigned long end, unsigned long *pfn_base)
+{
+       pmd_t *pmd;
+       pte_t *pte;
+       unsigned long addr, next;
+
+       for (addr = start; addr < end; addr = next) {
+               pmd = pmd_offset(pud, addr);
+
+               BUG_ON(pmd_sect(*pmd));
+
+               if (pmd_none(*pmd)) {
+                       pte = pte_alloc_one_kernel(NULL, addr);
+                       if (!pte) {
+                               kvm_err("Cannot allocate Hyp pte\n");
+                               return -ENOMEM;
+                       }
+                       pmd_populate_kernel(NULL, pmd, pte);
+               }
+
+               next = pmd_addr_end(addr, end);
+               create_hyp_pte_mappings(pmd, addr, next, pfn_base);
+       }
+
+       return 0;
+}
+
+static int __create_hyp_mappings(void *from, void *to, unsigned long *pfn_base)
+{
+       unsigned long start = (unsigned long)from;
+       unsigned long end = (unsigned long)to;
+       pgd_t *pgd;
+       pud_t *pud;
+       pmd_t *pmd;
+       unsigned long addr, next;
+       int err = 0;
+
+       BUG_ON(start > end);
+       if (start < PAGE_OFFSET)
+               return -EINVAL;
+
+       mutex_lock(&kvm_hyp_pgd_mutex);
+       for (addr = start; addr < end; addr = next) {
+               pgd = hyp_pgd + pgd_index(addr);
+               pud = pud_offset(pgd, addr);
+
+               if (pud_none_or_clear_bad(pud)) {
+                       pmd = pmd_alloc_one(NULL, addr);
+                       if (!pmd) {
+                               kvm_err("Cannot allocate Hyp pmd\n");
+                               err = -ENOMEM;
+                               goto out;
+                       }
+                       pud_populate(NULL, pud, pmd);
+               }
+
+               next = pgd_addr_end(addr, end);
+               err = create_hyp_pmd_mappings(pud, addr, next, pfn_base);
+               if (err)
+                       goto out;
+       }
+out:
+       mutex_unlock(&kvm_hyp_pgd_mutex);
+       return err;
+}
+
+/**
+ * create_hyp_mappings - map a kernel virtual address range in Hyp mode
+ * @from:      The virtual kernel start address of the range
+ * @to:                The virtual kernel end address of the range (exclusive)
+ *
+ * The same virtual address as the kernel virtual address is also used in
+ * Hyp-mode mapping to the same underlying physical pages.
+ *
+ * Note: Wrapping around zero in the "to" address is not supported.
+ */
+int create_hyp_mappings(void *from, void *to)
+{
+       return __create_hyp_mappings(from, to, NULL);
+}
+
+/**
+ * create_hyp_io_mappings - map a physical IO range in Hyp mode
+ * @from:      The virtual HYP start address of the range
+ * @to:                The virtual HYP end address of the range (exclusive)
+ * @addr:      The physical start address which gets mapped
+ */
+int create_hyp_io_mappings(void *from, void *to, phys_addr_t addr)
+{
+       unsigned long pfn = __phys_to_pfn(addr);
+       return __create_hyp_mappings(from, to, &pfn);
+}
+
+int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+       return -EINVAL;
+}
diff --git a/mm/memory.c b/mm/memory.c
index 5736170..0e58fdd 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -383,12 +383,14 @@ void pgd_clear_bad(pgd_t *pgd)
        pgd_ERROR(*pgd);
        pgd_clear(pgd);
 }
+EXPORT_SYMBOL_GPL(pgd_clear_bad);
 
 void pud_clear_bad(pud_t *pud)
 {
        pud_ERROR(*pud);
        pud_clear(pud);
 }
+EXPORT_SYMBOL_GPL(pud_clear_bad);
 
 void pmd_clear_bad(pmd_t *pmd)
 {

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