Commit eb8b0560 authored by Paul Mackerras's avatar Paul Mackerras Committed by Paul Mackerras
Browse files

KVM: PPC: Fix emulated MMIO sign-extension 



When the guest does a sign-extending load instruction (such as lha
or lwa) to an emulated MMIO location, it results in a call to
kvmppc_handle_loads() in the host.  That function sets the
vcpu->arch.mmio_sign_extend flag and calls kvmppc_handle_load()
to do the rest of the work.  However, kvmppc_handle_load() sets
the mmio_sign_extend flag to 0 unconditionally, so the sign
extension never gets done.

To fix this, we rename kvmppc_handle_load to __kvmppc_handle_load
and add an explicit parameter to indicate whether sign extension
is required.  kvmppc_handle_load() and kvmppc_handle_loads() then
become 1-line functions that just call __kvmppc_handle_load()
with the extra parameter.

Reported-by: default avatarBin Lu <lblulb@linux.vnet.ibm.com>
Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
Reviewed-by: default avatarThomas Huth <thuth@redhat.com>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent ade3ac66

arch/powerpc/kvm/powerpc.c

+12 −10
Original line number Diff line number Diff line
@@ -800,9 +800,9 @@ static void kvmppc_complete_mmio_load(struct kvm_vcpu *vcpu, 
	}

}



int kvmppc_handle_load(struct kvm_run *run, struct kvm_vcpu *vcpu,

static int __kvmppc_handle_load(struct kvm_run *run, struct kvm_vcpu *vcpu,

				unsigned int rt, unsigned int bytes,

		       int is_default_endian)

				int is_default_endian, int sign_extend)

{

	int idx, ret;

	bool host_swabbed;
@@ -827,7 +827,7 @@ int kvmppc_handle_load(struct kvm_run *run, struct kvm_vcpu *vcpu, 
	vcpu->arch.mmio_host_swabbed = host_swabbed;

	vcpu->mmio_needed = 1;

	vcpu->mmio_is_write = 0;

	vcpu->arch.mmio_sign_extend = 0;

	vcpu->arch.mmio_sign_extend = sign_extend;



	idx = srcu_read_lock(&vcpu->kvm->srcu);
@@ -844,6 +844,13 @@ int kvmppc_handle_load(struct kvm_run *run, struct kvm_vcpu *vcpu, 


	return EMULATE_DO_MMIO;

}



int kvmppc_handle_load(struct kvm_run *run, struct kvm_vcpu *vcpu,

		       unsigned int rt, unsigned int bytes,

		       int is_default_endian)

{

	return __kvmppc_handle_load(run, vcpu, rt, bytes, is_default_endian, 0);

}

EXPORT_SYMBOL_GPL(kvmppc_handle_load);



/* Same as above, but sign extends */
@@ -851,12 +858,7 @@ int kvmppc_handle_loads(struct kvm_run *run, struct kvm_vcpu *vcpu, 
			unsigned int rt, unsigned int bytes,

			int is_default_endian)

{

	int r;



	vcpu->arch.mmio_sign_extend = 1;

	r = kvmppc_handle_load(run, vcpu, rt, bytes, is_default_endian);



	return r;

	return __kvmppc_handle_load(run, vcpu, rt, bytes, is_default_endian, 1);

}



int kvmppc_handle_store(struct kvm_run *run, struct kvm_vcpu *vcpu,

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