4.9-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 0d640732dbebed0f10f18526de21652931f0b2f2 ]
When we emulate an MMIO instruction, we advance the CPU state within decode_hsr(), before emulating the instruction effects.
Having this logic in decode_hsr() is opaque, and advancing the state before emulation is problematic. It gets in the way of applying consistent single-step logic, and it prevents us from being able to fail an MMIO instruction with a synchronous exception.
Clean this up by only advancing the CPU state *after* the effects of the instruction are emulated.
Cc: Peter Maydell peter.maydell@linaro.org Reviewed-by: Alex Bennée alex.bennee@linaro.org Reviewed-by: Christoffer Dall christoffer.dall@arm.com Signed-off-by: Mark Rutland mark.rutland@arm.com Signed-off-by: Marc Zyngier marc.zyngier@arm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm/kvm/mmio.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/arch/arm/kvm/mmio.c b/arch/arm/kvm/mmio.c index dac7ceb1a677..08443a15e6be 100644 --- a/arch/arm/kvm/mmio.c +++ b/arch/arm/kvm/mmio.c @@ -117,6 +117,12 @@ int kvm_handle_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run) vcpu_set_reg(vcpu, vcpu->arch.mmio_decode.rt, data); }
+ /* + * The MMIO instruction is emulated and should not be re-executed + * in the guest. + */ + kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); + return 0; }
@@ -144,11 +150,6 @@ static int decode_hsr(struct kvm_vcpu *vcpu, bool *is_write, int *len) vcpu->arch.mmio_decode.sign_extend = sign_extend; vcpu->arch.mmio_decode.rt = rt;
- /* - * The MMIO instruction is emulated and should not be re-executed - * in the guest. - */ - kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); return 0; }