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Subject[PATCH v2 4/8] KVM: x86: move all vcpu->arch.pio* setup in emulator_pio_in_out()
Date
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>
---
arch/x86/kvm/trace.h | 2 +-
arch/x86/kvm/x86.c | 21 +++++++++++++--------
2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index bc85622e28b2..2120d7c060a9 100644
--- 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 5a56d39bd81f..368d0d4d56ff 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7576,17 +7576,25 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt,
}

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 @@ static int emulator_pio_in_out(struct kvm_vcpu *vcpu, int size,
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;

--
2.31.1

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