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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: Bin Lu <lblulb@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Paul Mackerras 2016-05-05 16:17:10 +10:00 committed by Paul Mackerras
parent ade3ac660a
commit eb8b056016
1 changed files with 12 additions and 10 deletions
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22
arch/powerpc/kvm/powerpc.c
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@ -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,