5 files changed, 53 insertions, 2 deletions

diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index 82c3b13e5d0a..3d07d9b1b815 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -382,6 +382,7 @@ struct kvm {
         struct kvm_pic *vpic;
         struct kvm_ioapic *vioapic;
         int round_robin_prev_vcpu;
+        unsigned int tss_addr;
 };
 
 static inline struct kvm_pic *pic_irqchip(struct kvm *kvm)
@@ -467,6 +468,8 @@ struct kvm_x86_ops {
         void (*inject_pending_irq)(struct kvm_vcpu *vcpu);
         void (*inject_pending_vectors)(struct kvm_vcpu *vcpu,
                                        struct kvm_run *run);
+
+        int (*set_tss_addr)(struct kvm *kvm, unsigned int addr);
 };
 
 extern struct kvm_x86_ops *kvm_x86_ops;
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index a044856bd02b..50fd040b9ea9 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -2661,6 +2661,16 @@ static int create_vcpu_fd(struct kvm_vcpu *vcpu)
         return fd;
 }
 
+static int kvm_vm_ioctl_set_tss_addr(struct kvm *kvm, unsigned long addr)
+{
+        int ret;
+
+        if (addr > (unsigned int)(-3 * PAGE_SIZE))
+                return -1;
+        ret = kvm_x86_ops->set_tss_addr(kvm, addr);
+        return ret;
+}
+
 /*
  * Creates some virtual cpus.  Good luck creating more than one.
  */
@@ -2957,6 +2967,11 @@ static long kvm_vm_ioctl(struct file *filp,
         int r = -EINVAL;
 
         switch (ioctl) {
+        case KVM_SET_TSS_ADDR:
+                r = kvm_vm_ioctl_set_tss_addr(kvm, arg);
+                if (r < 0)
+                        goto out;
+                break;
         case KVM_CREATE_VCPU:
                 r = kvm_vm_ioctl_create_vcpu(kvm, arg);
                 if (r < 0)
@@ -3183,6 +3198,7 @@ static long kvm_dev_ioctl(struct file *filp,
                 case KVM_CAP_HLT:
                 case KVM_CAP_MMU_SHADOW_CACHE_CONTROL:
                 case KVM_CAP_USER_MEMORY:
+                case KVM_CAP_SET_TSS_ADDR:
                         r = 1;
                         break;
                 default:
diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index 953c111544e1..beb1e684b68a 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -1439,6 +1439,11 @@ static void do_interrupt_requests(struct kvm_vcpu *vcpu,
                 control->intercept &= ~(1ULL << INTERCEPT_VINTR);
 }
 
+static int svm_set_tss_addr(struct kvm *kvm, unsigned int addr)
+{
+        return 0;
+}
+
 static void save_db_regs(unsigned long *db_regs)
 {
         asm volatile ("mov %%dr0, %0" : "=r"(db_regs[0]));
@@ -1744,6 +1749,8 @@ static struct kvm_x86_ops svm_x86_ops = {
         .set_irq = svm_set_irq,
         .inject_pending_irq = svm_intr_assist,
         .inject_pending_vectors = do_interrupt_requests,
+
+        .set_tss_addr = svm_set_tss_addr,
 };
 
 static int __init svm_init(void)
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 768ea88beb45..46b29184a4d8 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -1105,8 +1105,12 @@ static void enter_pmode(struct kvm_vcpu *vcpu)
 
 static gva_t rmode_tss_base(struct kvm *kvm)
 {
-        gfn_t base_gfn = kvm->memslots[0].base_gfn + kvm->memslots[0].npages - 3;
-        return base_gfn << PAGE_SHIFT;
+        if (!kvm->tss_addr) {
+                gfn_t base_gfn = kvm->memslots[0].base_gfn +
+                                 kvm->memslots[0].npages - 3;
+                return base_gfn << PAGE_SHIFT;
+        }
+        return kvm->tss_addr;
 }
 
 static void fix_rmode_seg(int seg, struct kvm_save_segment *save)
@@ -1735,6 +1739,23 @@ static void do_interrupt_requests(struct kvm_vcpu *vcpu,
         vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control);
 }
 
+static int vmx_set_tss_addr(struct kvm *kvm, unsigned int addr)
+{
+        int ret;
+        struct kvm_userspace_memory_region tss_mem = {
+                .slot = 8,
+                .guest_phys_addr = addr,
+                .memory_size = PAGE_SIZE * 3,
+                .flags = 0,
+        };
+
+        ret = kvm_set_memory_region(kvm, &tss_mem, 0);
+        if (ret)
+                return ret;
+        kvm->tss_addr = addr;
+        return 0;
+}
+
 static void kvm_guest_debug_pre(struct kvm_vcpu *vcpu)
 {
         struct kvm_guest_debug *dbg = &vcpu->guest_debug;
@@ -2543,6 +2564,8 @@ static struct kvm_x86_ops vmx_x86_ops = {
         .set_irq = vmx_inject_irq,
         .inject_pending_irq = vmx_intr_assist,
         .inject_pending_vectors = do_interrupt_requests,
+
+        .set_tss_addr = vmx_set_tss_addr,
 };
 
 static int __init vmx_init(void)
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 971f465e26fa..71d33d62944f 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -358,6 +358,7 @@ struct kvm_signal_mask {
 #define KVM_CAP_HLT       1
 #define KVM_CAP_MMU_SHADOW_CACHE_CONTROL 2
 #define KVM_CAP_USER_MEMORY 3
+#define KVM_CAP_SET_TSS_ADDR 4
 
 /*
  * ioctls for VM fds
@@ -367,6 +368,7 @@ struct kvm_signal_mask {
 #define KVM_GET_NR_MMU_PAGES      _IO(KVMIO, 0x45)
 #define KVM_SET_USER_MEMORY_REGION _IOW(KVMIO, 0x46,\
                                         struct kvm_userspace_memory_region)
+#define KVM_SET_TSS_ADDR          _IO(KVMIO, 0x47)
 /*
  * KVM_CREATE_VCPU receives as a parameter the vcpu slot, and returns
  * a vcpu fd.