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Re: [Qemu-ppc] [RFC 12/17] ppc: Migrate compatibility mode
From: |
Alexey Kardashevskiy |
Subject: |
Re: [Qemu-ppc] [RFC 12/17] ppc: Migrate compatibility mode |
Date: |
Fri, 4 Nov 2016 16:58:47 +1100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 |
On 30/10/16 22:12, David Gibson wrote:
> Server-class POWER CPUs can be put into several compatibility modes. These
> can be specified on the command line, or negotiated by the guest during
> boot.
>
> Currently we don't migrate the compatibility mode, which means after a
> migration the guest will revert to running with whatever compatibility
> mode (or none) specified on the command line.
>
> With the limited range of CPUs currently used, this doesn't usually cause
> a problem, but it could. Fix this by adding the compatibility mode (if
> set) to the migration stream.
>
> Signed-off-by: David Gibson <address@hidden>
> ---
> target-ppc/machine.c | 34 ++++++++++++++++++++++++++++++++++
> 1 file changed, 34 insertions(+)
>
> diff --git a/target-ppc/machine.c b/target-ppc/machine.c
> index 4820f22..5d87ff6 100644
> --- a/target-ppc/machine.c
> +++ b/target-ppc/machine.c
> @@ -9,6 +9,7 @@
> #include "mmu-hash64.h"
> #include "migration/cpu.h"
> #include "exec/exec-all.h"
> +#include "qapi/error.h"
>
> static int cpu_load_old(QEMUFile *f, void *opaque, int version_id)
> {
> @@ -176,6 +177,20 @@ static int cpu_post_load(void *opaque, int version_id)
> * software has to take care of running QEMU in a compatible mode.
> */
> env->spr[SPR_PVR] = env->spr_cb[SPR_PVR].default_value;
> +
> +#if defined(TARGET_PPC64)
> + if (cpu->compat_pvr) {
> + Error *local_err = NULL;
> +
> + ppc_set_compat(cpu, cpu->compat_pvr, &local_err);
> + if (local_err) {
> + error_report_err(local_err);
> + error_free(local_err);
> + return -1;
> + }
> + }
> +#endif
> +
> env->lr = env->spr[SPR_LR];
> env->ctr = env->spr[SPR_CTR];
> cpu_write_xer(env, env->spr[SPR_XER]);
> @@ -528,6 +543,24 @@ static const VMStateDescription vmstate_tlbmas = {
> }
> };
>
> +static bool compat_needed(void *opaque)
> +{
> + PowerPCCPU *cpu = opaque;
> +
> + return cpu->compat_pvr != 0;
Finally got to trying how this affects migration :)
This breaks migration to QEMU <=2.7, and it should not at least when both
source and destination are running with -cpu host,compat=power7.
> +}
> +
> +static const VMStateDescription vmstate_compat = {
> + .name = "cpu/compat",
> + .version_id = 1,
> + .minimum_version_id = 1,
> + .needed = compat_needed,
> + .fields = (VMStateField[]) {
> + VMSTATE_UINT32(compat_pvr, PowerPCCPU),
> + VMSTATE_END_OF_LIST()
> + }
> +};
> +
> const VMStateDescription vmstate_ppc_cpu = {
> .name = "cpu",
> .version_id = 5,
> @@ -580,6 +613,7 @@ const VMStateDescription vmstate_ppc_cpu = {
> &vmstate_tlb6xx,
> &vmstate_tlbemb,
> &vmstate_tlbmas,
> + &vmstate_compat,
> NULL
> }
> };
>
--
Alexey
- Re: [Qemu-ppc] [RFC 12/17] ppc: Migrate compatibility mode,
Alexey Kardashevskiy <=