KVM: x86: move all vcpu->arch.pio* setup in emulator_pio_in_out()

For now, this is basically an excuse to add back the void* argument to
the function, while removing some knowledge of vcpu->arch.pio* from
its callers.  The WARN that vcpu->arch.pio.count is zero is also
extended to OUT operations.

The vcpu->arch.pio* fields still need to be filled even when the PIO is
handled in-kernel as __emulator_pio_in() is always followed by
complete_emulator_pio_in().  But after fixing that, it will be possible to
to only populate the vcpu->arch.pio* fields on userspace exits.

No functional change intended.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index bc85622..2120d7c 100644 (file)
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -154,7 +154,7 @@ TRACE_EVENT(kvm_xen_hypercall,
 
 TRACE_EVENT(kvm_pio,
        TP_PROTO(unsigned int rw, unsigned int port, unsigned int size,
-                unsigned int count, void *data),
+                unsigned int count, const void *data),
        TP_ARGS(rw, port, size, count, data),
 
        TP_STRUCT__entry(

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5a56d39..368d0d4 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7576,17 +7576,25 @@ emul_write:
 }
 
 static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size,
-                              unsigned short port,
+                              unsigned short port, void *data,
                               unsigned int count, bool in)
 {
-       void *data = vcpu->arch.pio_data;
        unsigned i;
        int r;
 
+       WARN_ON_ONCE(vcpu->arch.pio.count);
        vcpu->arch.pio.port = port;
        vcpu->arch.pio.in = in;
        vcpu->arch.pio.count = count;
        vcpu->arch.pio.size = size;
+       if (in) {
+               /* The buffer is only used in complete_emulator_pio_in().  */
+               WARN_ON(data);
+               memset(vcpu->arch.pio_data, 0, size * count);
+       } else {
+               memcpy(vcpu->arch.pio_data, data, size * count);
+       }
+       data = vcpu->arch.pio_data;
 
        for (i = 0; i < count; i++) {
                if (in)
@@ -7623,9 +7631,7 @@ userspace_io:
 static int __emulator_pio_in(struct kvm_vcpu *vcpu, int size,
                             unsigned short port, unsigned int count)
 {
-       WARN_ON(vcpu->arch.pio.count);
-       memset(vcpu->arch.pio_data, 0, size * count);
-       return emulator_pio_in_out(vcpu, size, port, count, true);
+       return emulator_pio_in_out(vcpu, size, port, NULL, count, true);
 }
 
 static void complete_emulator_pio_in(struct kvm_vcpu *vcpu, void *val)
@@ -7674,9 +7680,8 @@ static int emulator_pio_out(struct kvm_vcpu *vcpu, int size,
 {
        int ret;
 
-       memcpy(vcpu->arch.pio_data, val, size * count);
-       trace_kvm_pio(KVM_PIO_OUT, port, size, count, vcpu->arch.pio_data);
-       ret = emulator_pio_in_out(vcpu, size, port, count, false);
+       trace_kvm_pio(KVM_PIO_OUT, port, size, count, val);
+       ret = emulator_pio_in_out(vcpu, size, port, (void *)val, count, false);
        if (ret)
                 vcpu->arch.pio.count = 0;