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arm/arm64: KVM: avoid unnecessary guest register mangling on MMIO read 

Currently we mangle the endianness of the guest's register even on an
MMIO _read_, where it is completely useless, because we will not use
the value of that register.
Rework the io_mem_abort() function to clearly separate between reads
and writes and only do the endianness mangling on MMIO writes.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Andre Przywara 2014-11-06 12:11:45 +00:00 committed by Marc Zyngier
parent 849260c72c
commit 5100f9833e
1 changed files with 9 additions and 6 deletions
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15
arch/arm/kvm/mmio.c
View File

@ -187,15 +187,18 @@ int io_mem_abort(struct kvm_vcpu *vcpu, struct kvm_run *run,
}
rt = vcpu->arch.mmio_decode.rt;
data = vcpu_data_guest_to_host(vcpu, *vcpu_reg(vcpu, rt), mmio.len);
trace_kvm_mmio((mmio.is_write) ? KVM_TRACE_MMIO_WRITE :
KVM_TRACE_MMIO_READ_UNSATISFIED,
mmio.len, fault_ipa,
(mmio.is_write) ? data : 0);
if (mmio.is_write) {
data = vcpu_data_guest_to_host(vcpu, *vcpu_reg(vcpu, rt),
mmio.len);
if (mmio.is_write)
trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, mmio.len,
fault_ipa, data);
mmio_write_buf(mmio.data, mmio.len, data);
} else {
trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, mmio.len,
fault_ipa, 0);
}
if (vgic_handle_mmio(vcpu, run, &mmio))
return 1;