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Re: [Qemu-devel] ppc64 not resuming with v2.3.0-rc3
From: |
Mark Cave-Ayland |
Subject: |
Re: [Qemu-devel] ppc64 not resuming with v2.3.0-rc3 |
Date: |
Thu, 16 Apr 2015 20:42:07 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.6.0 |
On 16/04/15 17:43, Stefan Berger wrote:
> The culprit patch seems to be the following commit. If I remove these
> changes from the tip of the tree it works again (on SLOF level):
>
> commit 2360b6e84f78d41fa0f76555a947148b73645259
> Author: Mark Cave-Ayland <address@hidden>
> Date: Mon Feb 9 22:40:48 2015 +0000
>
> target-ppc: force update of msr bits in cpu_post_load
>
> Since env->msr has already been restored by the time cpu_post_load
> is called,
> make sure that ppc_store_msr() is explicitly called with all msr
> bits except
> MSR_TGPR marked as invalid.
>
> This solves the issue where MSR flags aren't set correctly when
> restoring a VM
> snapshot, in particular the internal env->excp_prefix value when
> MSR_EP has
> been altered by a guest.
>
> Signed-off-by: Mark Cave-Ayland <address@hidden>
> Signed-off-by: Alexander Graf <address@hidden>
>
> diff --git a/target-ppc/machine.c b/target-ppc/machine.c
> index c801b82..3921012 100644
> --- a/target-ppc/machine.c
> +++ b/target-ppc/machine.c
> @@ -159,6 +159,7 @@ static int cpu_post_load(void *opaque, int version_id)
> PowerPCCPU *cpu = opaque;
> CPUPPCState *env = &cpu->env;
> int i;
> + target_ulong msr;
>
> /*
> * We always ignore the source PVR. The user or management
> @@ -190,7 +191,12 @@ static int cpu_post_load(void *opaque, int version_id)
> /* Restore htab_base and htab_mask variables */
> ppc_store_sdr1(env, env->spr[SPR_SDR1]);
> }
> - hreg_compute_hflags(env);
> +
> + /* Mark msr bits except MSR_TGPR invalid before restoring */
> + msr = env->msr;
> + env->msr ^= ~(1ULL << MSR_TGPR);
> + ppc_store_msr(env, msr);
> +
> hreg_compute_mem_idx(env);
>
> return 0;
>
>
> Stefan
>
> PS: Sorry for the late notice (-rc3), but I only started doing things
> with ppc64 a few days ago.
Hmmmm the fix is correct in that internal MSR variables need to be
updated post-restore (as noted in the message above it was the exception
prefix variables that weren't updated by having MSR_EP set).
Maybe on ppc64 there is another bit similar to MSR_TGPR that needs to be
excluded? Alex, any thoughts?
ATB,
Mark.