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: Bin Lu <lblulb@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Paul Mackerras <paulus@xxxxxxxxxx>
---
arch/powerpc/kvm/powerpc.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 6a68730..02416fe 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -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,
- unsigned int rt, unsigned int bytes,
- int is_default_endian)
+static int __kvmppc_handle_load(struct kvm_run *run, struct kvm_vcpu *vcpu,
+ unsigned int rt, unsigned int bytes,
+ 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,
--
2.8.0.rc3
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