Commit 708e75a3 authored by Thomas Huth's avatar Thomas Huth Committed by Paul Mackerras

KVM: PPC: Book3S PR: Fix illegal opcode emulation

If kvmppc_handle_exit_pr() calls kvmppc_emulate_instruction() to emulate
one instruction (in the BOOK3S_INTERRUPT_H_EMUL_ASSIST case), it calls
kvmppc_core_queue_program() afterwards if kvmppc_emulate_instruction()
returned EMULATE_FAIL, so the guest gets an program interrupt for the
illegal opcode.
However, the kvmppc_emulate_instruction() also tried to inject a
program exception for this already, so the program interrupt gets
injected twice and the return address in srr0 gets destroyed.
All other callers of kvmppc_emulate_instruction() are also injecting
a program interrupt, and since the callers have the right knowledge
about the srr1 flags that should be used, it is the function
kvmppc_emulate_instruction() that should _not_ inject program
interrupts, so remove the kvmppc_core_queue_program() here.

This fixes the issue discovered by Laurent Vivier with kvm-unit-tests
where the logs are filled with these messages when the test tries
to execute an illegal instruction:

     Couldn't emulate instruction 0x00000000 (op 0 xop 0)
     kvmppc_handle_exit_pr: emulation at 700 failed (00000000)
Signed-off-by: default avatarThomas Huth <thuth@redhat.com>
Reviewed-by: default avatarAlexander Graf <agraf@suse.de>
Tested-by: default avatarLaurent Vivier <lvivier@redhat.com>
Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
parent 64672c95
......@@ -302,7 +302,6 @@ int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
advance = 0;
printk(KERN_ERR "Couldn't emulate instruction 0x%08x "
"(op %d xop %d)\n", inst, get_op(inst), get_xop(inst));
kvmppc_core_queue_program(vcpu, 0);
}
}
......
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