Re: [PATCH] kvm-pr: manage illegal instructions
From: Laurent Vivier
Date: Tue Mar 22 2016 - 06:11:40 EST
Hi,
as Paolo has merged the test into kvm-unit-tests, this patch (and
original bug) can be now tested with it.
git://git.kernel.org/pub/scm/virt/kvm/kvm-unit-tests.git
at least:
be9b007 powerpc: add test to check invalid instruction trap
Run this with KVM-PR and check your dmesg:
qemu-system-ppc64 -machine pseries,accel=kvm \
-bios powerpc/boot_rom.bin \
-display none -serial stdio \
-kernel powerpc/emulator.elf -smp 1
Laurent
On 15/03/2016 21:18, Laurent Vivier wrote:
> While writing some instruction tests for kvm-unit-tests for powerpc,
> I've found that illegal instructions are not managed correctly with kvm-pr,
> while it is fine with kvm-hv.
>
> When an illegal instruction (like ".long 0") is processed by kvm-pr,
> the kernel logs are filled with:
>
> Couldn't emulate instruction 0x00000000 (op 0 xop 0)
> kvmppc_handle_exit_pr: emulation at 700 failed (00000000)
>
> While the exception handler receives an interrupt for each instruction
> executed after the illegal instruction.
>
> Signed-off-by: Laurent Vivier <lvivier@xxxxxxxxxx>
> ---
> arch/powerpc/kvm/book3s_emulate.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/kvm/book3s_emulate.c b/arch/powerpc/kvm/book3s_emulate.c
> index 2afdb9c..4ee969d 100644
> --- a/arch/powerpc/kvm/book3s_emulate.c
> +++ b/arch/powerpc/kvm/book3s_emulate.c
> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct kvm_vcpu *vcpu,
>
> switch (get_op(inst)) {
> case 0:
> - emulated = EMULATE_FAIL;
> if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
> (inst == swab32(inst_sc))) {
> /*
> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct kvm_vcpu *vcpu,
> kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
> kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
> emulated = EMULATE_DONE;
> + } else {
> + kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
> + emulated = EMULATE_AGAIN;
> }
> break;
> case 19:
>