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authorRadim Krčmář <rkrcmar@redhat.com>2018-05-24 17:50:56 +0200
committerRadim Krčmář <rkrcmar@redhat.com>2018-05-25 21:33:31 +0200
commit696ca779a928d0e93d61c38ffc3a4d8914a9b9a0 (patch)
tree2c402b64e57a7e751e75cbc2cb2dac6256b7e73a
parent1eaafe91a0df4157521b6417b3dd8430bf5f52f0 (diff)
downloadlinux-stericsson-696ca779a928d0e93d61c38ffc3a4d8914a9b9a0.tar.gz
KVM: x86: fix #UD address of failed Hyper-V hypercalls
If the hypercall was called from userspace or real mode, KVM injects #UD and then advances RIP, so it looks like #UD was caused by the following instruction. This probably won't cause more than confusion, but could give an unexpected access to guest OS' instruction emulator. Also, refactor the code to count hv hypercalls that were handled by the virt userspace. Fixes: 6356ee0c9602 ("x86: Delay skip of emulated hypercall instruction") Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
-rw-r--r--arch/x86/kvm/hyperv.c19
-rw-r--r--arch/x86/kvm/x86.c12
2 files changed, 15 insertions, 16 deletions
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 5708e951a5c6..46ff64da44ca 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1260,14 +1260,18 @@ static void kvm_hv_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result)
}
}
-static int kvm_hv_hypercall_complete_userspace(struct kvm_vcpu *vcpu)
+static int kvm_hv_hypercall_complete(struct kvm_vcpu *vcpu, u64 result)
{
- struct kvm_run *run = vcpu->run;
-
- kvm_hv_hypercall_set_result(vcpu, run->hyperv.u.hcall.result);
+ kvm_hv_hypercall_set_result(vcpu, result);
+ ++vcpu->stat.hypercalls;
return kvm_skip_emulated_instruction(vcpu);
}
+static int kvm_hv_hypercall_complete_userspace(struct kvm_vcpu *vcpu)
+{
+ return kvm_hv_hypercall_complete(vcpu, vcpu->run->hyperv.u.hcall.result);
+}
+
static u16 kvm_hvcall_signal_event(struct kvm_vcpu *vcpu, bool fast, u64 param)
{
struct eventfd_ctx *eventfd;
@@ -1350,7 +1354,7 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
/* Hypercall continuation is not supported yet */
if (rep_cnt || rep_idx) {
ret = HV_STATUS_INVALID_HYPERCALL_CODE;
- goto set_result;
+ goto out;
}
switch (code) {
@@ -1381,9 +1385,8 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
break;
}
-set_result:
- kvm_hv_hypercall_set_result(vcpu, ret);
- return 1;
+out:
+ return kvm_hv_hypercall_complete(vcpu, ret);
}
void kvm_hv_init_vm(struct kvm *kvm)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e3103279eadd..b7618b30b7d6 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6676,11 +6676,8 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
unsigned long nr, a0, a1, a2, a3, ret;
int op_64_bit;
- if (kvm_hv_hypercall_enabled(vcpu->kvm)) {
- if (!kvm_hv_hypercall(vcpu))
- return 0;
- goto out;
- }
+ if (kvm_hv_hypercall_enabled(vcpu->kvm))
+ return kvm_hv_hypercall(vcpu);
nr = kvm_register_read(vcpu, VCPU_REGS_RAX);
a0 = kvm_register_read(vcpu, VCPU_REGS_RBX);
@@ -6701,7 +6698,7 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
if (kvm_x86_ops->get_cpl(vcpu) != 0) {
ret = -KVM_EPERM;
- goto out_error;
+ goto out;
}
switch (nr) {
@@ -6721,12 +6718,11 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
ret = -KVM_ENOSYS;
break;
}
-out_error:
+out:
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);
}