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Commit 5100f983 authored by Andre Przywara's avatar Andre Przywara Committed by Marc Zyngier
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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: default avatarAndre Przywara <andre.przywara@arm.com>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 849260c7

arch/arm/kvm/mmio.c

+9 −6
Original line number Diff line number Diff line
@@ -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;