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Subject[PATCH 5.14 112/169] KVM: x86: leave vcpu->arch.pio.count alone in emulator_pio_in_out
Date
From: Paolo Bonzini <pbonzini@redhat.com>

commit 0d33b1baeb6ca7165d5ed4fdd1a8f969985e35b9 upstream.

Currently emulator_pio_in clears vcpu->arch.pio.count twice if
emulator_pio_in_out performs kernel PIO. Move the clear into
emulator_pio_out where it is actually necessary.

No functional change intended.

Cc: stable@vger.kernel.org
Fixes: 7ed9abfe8e9f ("KVM: SVM: Support string IO operations for an SEV-ES guest")
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kvm/x86.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)

--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6915,10 +6915,8 @@ static int emulator_pio_in_out(struct kv
vcpu->arch.pio.count = count;
vcpu->arch.pio.size = size;

- if (!kernel_pio(vcpu, vcpu->arch.pio_data)) {
- vcpu->arch.pio.count = 0;
+ if (!kernel_pio(vcpu, vcpu->arch.pio_data))
return 1;
- }

vcpu->run->exit_reason = KVM_EXIT_IO;
vcpu->run->io.direction = in ? KVM_EXIT_IO_IN : KVM_EXIT_IO_OUT;
@@ -6964,9 +6962,16 @@ static int emulator_pio_out(struct kvm_v
unsigned short port, const void *val,
unsigned int count)
{
+ int ret;
+
memcpy(vcpu->arch.pio_data, val, size * count);
trace_kvm_pio(KVM_PIO_OUT, port, size, count, vcpu->arch.pio_data);
- return emulator_pio_in_out(vcpu, size, port, (void *)val, count, false);
+ ret = emulator_pio_in_out(vcpu, size, port, (void *)val, count, false);
+ if (ret)
+ vcpu->arch.pio.count = 0;
+
+ return ret;
+
}

static int emulator_pio_out_emulated(struct x86_emulate_ctxt *ctxt,

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