On 30/04/2018 11:23, Marian Rotariu wrote:
> The IP increment should be done after the hypercall emulation, after
> calling the various handlers. In this way, these handlers can accurately
> identify the the IP of the VMCALL if they need it.
>
> This patch keeps the same functionality for the Hyper-V handler which does
> not use the return code of the standard kvm_skip_emulated_instruction()
> call.
That is actually a bug. Let's squash this in the patch (pending testing
of course):
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 98618e397342..a41cb6d61ca2 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1265,7 +1265,7 @@ static int kvm_hv_hypercall_complete_userspace(struct kvm_vcpu *vcpu)
struct kvm_run *run = vcpu->run;
kvm_hv_hypercall_set_result(vcpu, run->hyperv.u.hcall.result);
- return 1;
+ return kvm_skip_emulated_instruction(vcpu);
}
static u16 kvm_hvcall_signal_event(struct kvm_vcpu *vcpu, bool fast, u64 param)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 98deda7694a2..37dd9a9d050a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6677,8 +6677,9 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
int op_64_bit;
if (kvm_hv_hypercall_enabled(vcpu->kvm)) {
- kvm_skip_emulated_instruction(vcpu);
- return kvm_hv_hypercall(vcpu);
+ if (!kvm_hv_hypercall(vcpu))
+ return 0;
+ goto out;
}
nr = kvm_register_read(vcpu, VCPU_REGS_RAX);
@@ -6700,7 +6701,7 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
if (kvm_x86_ops->get_cpl(vcpu) != 0) {
ret = -KVM_EPERM;
- goto out;
+ goto out_error;
}
switch (nr) {
@@ -6720,10 +6721,12 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
ret = -KVM_ENOSYS;
break;
}
-out:
+out_error:
if (!op_64_bit)
ret = (u32)ret;
kvm_register_write(vcpu, VCPU_REGS_RAX, ret);
+
+out:
++vcpu->stat.hypercalls;
return kvm_skip_emulated_instruction(vcpu);
}
