KVM: Refactor hypercall infrastructure (v3)
This patch refactors the current hypercall infrastructure to better
support live migration and SMP. It eliminates the hypercall page by
trapping the UD exception that would occur if you used the wrong hypercall
instruction for the underlying architecture and replacing it with the right
one lazily.
A fall-out of this patch is that the unhandled hypercalls no longer trap to
userspace. There is very little reason though to use a hypercall to
communicate with userspace as PIO or MMIO can be used. There is no code
in tree that uses userspace hypercalls.
[avi: fix #ud injection on vmx]
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index ced4ac1..794d954 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -476,7 +476,8 @@
INTERCEPT_DR5_MASK |
INTERCEPT_DR7_MASK;
- control->intercept_exceptions = 1 << PF_VECTOR;
+ control->intercept_exceptions = (1 << PF_VECTOR) |
+ (1 << UD_VECTOR);
control->intercept = (1ULL << INTERCEPT_INTR) |
@@ -979,6 +980,17 @@
return 0;
}
+static int ud_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
+{
+ int er;
+
+ er = emulate_instruction(&svm->vcpu, kvm_run, 0, 0);
+ if (er != EMULATE_DONE)
+ inject_ud(&svm->vcpu);
+
+ return 1;
+}
+
static int nm_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
svm->vmcb->control.intercept_exceptions &= ~(1 << NM_VECTOR);
@@ -1045,7 +1057,8 @@
{
svm->next_rip = svm->vmcb->save.rip + 3;
skip_emulated_instruction(&svm->vcpu);
- return kvm_hypercall(&svm->vcpu, kvm_run);
+ kvm_emulate_hypercall(&svm->vcpu);
+ return 1;
}
static int invalid_op_interception(struct vcpu_svm *svm,
@@ -1241,6 +1254,7 @@
[SVM_EXIT_WRITE_DR3] = emulate_on_interception,
[SVM_EXIT_WRITE_DR5] = emulate_on_interception,
[SVM_EXIT_WRITE_DR7] = emulate_on_interception,
+ [SVM_EXIT_EXCP_BASE + UD_VECTOR] = ud_interception,
[SVM_EXIT_EXCP_BASE + PF_VECTOR] = pf_interception,
[SVM_EXIT_EXCP_BASE + NM_VECTOR] = nm_interception,
[SVM_EXIT_INTR] = nop_on_interception,
@@ -1675,7 +1689,6 @@
hypercall[0] = 0x0f;
hypercall[1] = 0x01;
hypercall[2] = 0xd9;
- hypercall[3] = 0xc3;
}
static void svm_check_processor_compat(void *rtn)