[PATCH] KVM: SVM: Propagate cpu shutdown events to userspace

This patch implements forwarding of SHUTDOWN intercepts from the guest on to
userspace on AMD SVM.  A SHUTDOWN event occurs when the guest produces a
triple fault (e.g.  on reboot).  This also fixes the bug that a guest reboot
actually causes a host reboot under some circumstances.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 16 insertions, 0 deletions

diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index 717aabb012cc..9c70ff65e6b7 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -502,6 +502,7 @@ static void init_vmcb(struct vmcb *vmcb)
                                 (1ULL << INTERCEPT_IOIO_PROT) |
                                 (1ULL << INTERCEPT_MSR_PROT) |
                                 (1ULL << INTERCEPT_TASK_SWITCH) |
+                                (1ULL << INTERCEPT_SHUTDOWN) |
                                 (1ULL << INTERCEPT_VMRUN) |
                                 (1ULL << INTERCEPT_VMMCALL) |
                                 (1ULL << INTERCEPT_VMLOAD) |
@@ -892,6 +893,19 @@ static int pf_interception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
         return 0;
 }
 
+static int shutdown_interception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
+{
+        /*
+         * VMCB is undefined after a SHUTDOWN intercept
+         * so reinitialize it.
+         */
+        memset(vcpu->svm->vmcb, 0, PAGE_SIZE);
+        init_vmcb(vcpu->svm->vmcb);
+
+        kvm_run->exit_reason = KVM_EXIT_SHUTDOWN;
+        return 0;
+}
+
 static int io_get_override(struct kvm_vcpu *vcpu,
                           struct vmcb_seg **seg,
                           int *addr_override)
@@ -1249,6 +1263,7 @@ static int (*svm_exit_handlers[])(struct kvm_vcpu *vcpu,
         [SVM_EXIT_IOIO]                         = io_interception,
         [SVM_EXIT_MSR]                          = msr_interception,
         [SVM_EXIT_TASK_SWITCH]                  = task_switch_interception,
+        [SVM_EXIT_SHUTDOWN]                     = shutdown_interception,
         [SVM_EXIT_VMRUN]                        = invalid_op_interception,
         [SVM_EXIT_VMMCALL]                      = invalid_op_interception,
         [SVM_EXIT_VMLOAD]                       = invalid_op_interception,
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index bc8b4616bad7..1be148f0fce4 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -46,6 +46,7 @@ enum kvm_exit_reason {
         KVM_EXIT_HLT              = 5,
         KVM_EXIT_MMIO             = 6,
         KVM_EXIT_IRQ_WINDOW_OPEN  = 7,
+        KVM_EXIT_SHUTDOWN         = 8,
 };
 
 /* for KVM_RUN */