This is a note to let you know that I've just added the patch titled
KVM: PPC: Book3S PR: Fix illegal opcode emulation
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-ppc-book3s-pr-fix-illegal-opcode-emulation.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 708e75a3ee750dce1072134e630d66c4e6eaf63c Mon Sep 17 00:00:00 2001
From: Thomas Huth <thuth@xxxxxxxxxx>
Date: Wed, 18 May 2016 21:01:20 +0200
Subject: KVM: PPC: Book3S PR: Fix illegal opcode emulation
From: Thomas Huth <thuth@xxxxxxxxxx>
commit 708e75a3ee750dce1072134e630d66c4e6eaf63c upstream.
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: Thomas Huth <thuth@xxxxxxxxxx>
Reviewed-by: Alexander Graf <agraf@xxxxxxx>
Tested-by: Laurent Vivier <lvivier@xxxxxxxxxx>
Signed-off-by: Paul Mackerras <paulus@xxxxxxxxxx>
Cc: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/kvm/emulate.c | 1 -
1 file changed, 1 deletion(-)
--- a/arch/powerpc/kvm/emulate.c
+++ b/arch/powerpc/kvm/emulate.c
@@ -302,7 +302,6 @@ int kvmppc_emulate_instruction(struct kv
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);
}
}
Patches currently in stable-queue which might be from thuth@xxxxxxxxxx are
queue-4.4/kvm-ppc-book3s-pr-fix-illegal-opcode-emulation.patch