[Qemu-devel] [PATCH v2 5/5] kvm/x86: Hyper-V VMBus hypercall userspace exit

[Andrey Smetanin]

The patch implements KVM_EXIT_HYPERV userspace exit
functionality for Hyper-V VMBus hypercalls:
HV_X64_HCALL_POST_MESSAGE, HV_X64_HCALL_SIGNAL_EVENT.

Changes v2:
* use KVM_EXIT_HYPERV for hypercalls

Signed-off-by: Andrey Smetanin <address@hidden>
Reviewed-by: Roman Kagan <address@hidden>
CC: Gleb Natapov <address@hidden>
CC: Paolo Bonzini <address@hidden>
CC: Joerg Roedel <address@hidden>
CC: "K. Y. Srinivasan" <address@hidden>
CC: Haiyang Zhang <address@hidden>
CC: Roman Kagan <address@hidden>
CC: Denis V. Lunev <address@hidden>
CC: address@hidden
---
 Documentation/virtual/kvm/api.txt |  6 ++++++
 arch/x86/kvm/hyperv.c             | 29 ++++++++++++++++++++++-------
 arch/x86/kvm/hyperv.h             |  1 +
 arch/x86/kvm/x86.c                |  5 +++++
 include/uapi/linux/kvm.h          |  6 ++++++
 5 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/Documentation/virtual/kvm/api.txt 
b/Documentation/virtual/kvm/api.txt
index 053f613..1bf1a07 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -3339,6 +3339,7 @@ EOI was received.
 
                struct kvm_hyperv_exit {
 #define KVM_EXIT_HYPERV_SYNIC          1
+#define KVM_EXIT_HYPERV_HCALL          2
                        __u32 type;
                        union {
                                struct {
@@ -3347,6 +3348,11 @@ EOI was received.
                                        __u64 evt_page;
                                        __u64 msg_page;
                                } synic;
+                               struct {
+                                       __u64 input;
+                                       __u64 result;
+                                       __u64 params[2];
+                               } hcall;
                        } u;
                };
                /* KVM_EXIT_HYPERV */
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index e1daa8b..26ae973 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1093,6 +1093,14 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
        case HV_X64_HCALL_NOTIFY_LONG_SPIN_WAIT:
                kvm_vcpu_on_spin(vcpu);
                break;
+       case HV_X64_HCALL_POST_MESSAGE:
+       case HV_X64_HCALL_SIGNAL_EVENT:
+               vcpu->run->exit_reason = KVM_EXIT_HYPERV;
+               vcpu->run->hyperv.type = KVM_EXIT_HYPERV_HCALL;
+               vcpu->run->hyperv.u.hcall.input = param;
+               vcpu->run->hyperv.u.hcall.params[0] = ingpa;
+               vcpu->run->hyperv.u.hcall.params[1] = outgpa;
+               return 0;
        default:
                res = HV_STATUS_INVALID_HYPERCALL_CODE;
                break;
@@ -1100,12 +1108,19 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
 
 set_result:
        ret = res | (((u64)rep_done & 0xfff) << 32);
-       if (longmode) {
-               kvm_register_write(vcpu, VCPU_REGS_RAX, ret);
-       } else {
-               kvm_register_write(vcpu, VCPU_REGS_RDX, ret >> 32);
-               kvm_register_write(vcpu, VCPU_REGS_RAX, ret & 0xffffffff);
-       }
-
+       kvm_hv_hypercall_set_result(vcpu, ret);
        return 1;
 }
+
+void kvm_hv_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result)
+{
+       bool longmode;
+
+       longmode = is_64_bit_mode(vcpu);
+       if (longmode)
+               kvm_register_write(vcpu, VCPU_REGS_RAX, result);
+       else {
+               kvm_register_write(vcpu, VCPU_REGS_RDX, result >> 32);
+               kvm_register_write(vcpu, VCPU_REGS_RAX, result & 0xffffffff);
+       }
+}
diff --git a/arch/x86/kvm/hyperv.h b/arch/x86/kvm/hyperv.h
index 60eccd4..64a4a3b 100644
--- a/arch/x86/kvm/hyperv.h
+++ b/arch/x86/kvm/hyperv.h
@@ -52,6 +52,7 @@ int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 
*pdata);
 
 bool kvm_hv_hypercall_enabled(struct kvm *kvm);
 int kvm_hv_hypercall(struct kvm_vcpu *vcpu);
+void kvm_hv_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result);
 
 void kvm_hv_irq_routing_update(struct kvm *kvm);
 int kvm_hv_synic_set_irq(struct kvm *kvm, u32 vcpu_id, u32 sint);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f53f5b1..e5c842b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6891,6 +6891,11 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, 
struct kvm_run *kvm_run)
        } else
                WARN_ON(vcpu->arch.pio.count || vcpu->mmio_needed);
 
+       if (unlikely(kvm_run->exit_reason == KVM_EXIT_HYPERV) &&
+           kvm_run->hyperv.type == KVM_EXIT_HYPERV_HCALL)
+               kvm_hv_hypercall_set_result(vcpu,
+                                           kvm_run->hyperv.u.hcall.result);
+
        r = vcpu_run(vcpu);
 
 out:
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 9da9051..c5519a9 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -157,6 +157,7 @@ struct kvm_s390_skeys {
 
 struct kvm_hyperv_exit {
 #define KVM_EXIT_HYPERV_SYNIC          1
+#define KVM_EXIT_HYPERV_HCALL          2
        __u32 type;
        union {
                struct {
@@ -165,6 +166,11 @@ struct kvm_hyperv_exit {
                        __u64 evt_page;
                        __u64 msg_page;
                } synic;
+               struct {
+                       __u64 input;
+                       __u64 result;
+                       __u64 params[2];
+               } hcall;
        } u;
 };
 
-- 
2.4.3