From eb8b0560160d8363bc40ca05a75ef144cebaae72 Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Thu, 5 May 2016 16:17:10 +1000 Subject: [PATCH] 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 Signed-off-by: Paul Mackerras Reviewed-by: Thomas Huth Signed-off-by: Paul Mackerras --- 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 6a68730774ee..02416fea7653 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, -- 2.20.1