[PATCH] x86: svm: use kvm_fast_pio_in()

From: Joel Schopp
Date: Fri Feb 27 2015 - 19:13:51 EST


From: David Kaplan <David.Kaplan@xxxxxxx>

We can make the in instruction go faster the same way the out instruction is
already.

Signed-off-by: David Kaplan <David.Kaplan@xxxxxxx>
[extracted from larger unlrelated patch, forward ported, tested]
Signed-off-by: Joel Schopp <joel.schopp@xxxxxxx>
---
arch/x86/kvm/svm.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index d319e0c..f8c906b 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1899,7 +1899,7 @@ static int io_interception(struct vcpu_svm *svm)
++svm->vcpu.stat.io_exits;
string = (io_info & SVM_IOIO_STR_MASK) != 0;
in = (io_info & SVM_IOIO_TYPE_MASK) != 0;
- if (string || in)
+ if (string)
return emulate_instruction(vcpu, 0) == EMULATE_DONE;

port = io_info >> 16;
@@ -1907,6 +1907,8 @@ static int io_interception(struct vcpu_svm *svm)
svm->next_rip = svm->vmcb->control.exit_info_2;
skip_emulated_instruction(&svm->vcpu);

+ if (in)
+ return kvm_fast_pio_in(vcpu, size, port);
return kvm_fast_pio_out(vcpu, size, port);
}


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