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Re: [Qemu-ppc] [PATCH] ppc: initialize GPRs as per epapr
From: |
Bhushan Bharat-R65777 |
Subject: |
Re: [Qemu-ppc] [PATCH] ppc: initialize GPRs as per epapr |
Date: |
Fri, 26 Apr 2013 06:51:35 +0000 |
> -----Original Message-----
> From: Alexander Graf [mailto:address@hidden
> Sent: Friday, April 26, 2013 11:51 AM
> To: Bhushan Bharat-R65777
> Cc: address@hidden; address@hidden; Wood Scott-B07421; Bhushan
> Bharat-R65777; Yoder Stuart-B08248
> Subject: Re: [PATCH] ppc: initialize GPRs as per epapr
>
>
> On 26.04.2013, at 08:17, Bharat Bhushan wrote:
>
> > ePAPR defines the initial values of cpu registers. This patch
> > initialize the GPRs as per ePAPR specification.
> >
> > This resolves the issue of guest reboot/reset (guest hang on reboot).
>
> Why does it hang only on reboot, not on initial bootup?
may be memory pointed by env pointer are zero initialized initially.
Reboot also not always hangs. I have seen reboot mostly working on
e500v2/e500mc and mostly hanging on e5500.
>
> >
> > Signed-off-by: Bharat Bhushan <address@hidden>
> > Signed-off-by: Stuart Yoder <address@hidden>
> > ---
> > hw/ppc/e500.c | 7 +++++++
> > 1 files changed, 7 insertions(+), 0 deletions(-)
> >
> > diff --git a/hw/ppc/e500.c b/hw/ppc/e500.c index c1bdb6b..a47f976
> > 100644
> > --- a/hw/ppc/e500.c
> > +++ b/hw/ppc/e500.c
> > @@ -37,6 +37,7 @@
> > #include "qemu/host-utils.h"
> > #include "hw/pci-host/ppce500.h"
> >
> > +#define EPAPR_MAGIC (0x45504150)
> > #define BINARY_DEVICE_TREE_FILE "mpc8544ds.dtb"
> > #define UIMAGE_LOAD_BASE 0
> > #define DTC_LOAD_PAD 0x1800000
> > @@ -444,6 +445,12 @@ static void ppce500_cpu_reset(void *opaque)
>
> Does ePAPR mention anything wrt GPR state of secondary CPUs?
Yes, I think we handle this in hw/ppc/ppce500_spin.c
>
> > cs->halted = 0;
> > env->gpr[1] = (16<<20) - 8;
> > env->gpr[3] = bi->dt_base;
> > + env->gpr[4] = 0;
> > + env->gpr[5] = 0;
> > + env->gpr[6] = EPAPR_MAGIC;
> > + env->gpr[7] = (64 * 1024 * 1024);
>
> What is this?
Size of initial TLB ( should be big enough to cover kernel handler). I do not
see ePAPR defines any value, I set this to 64M.
-Bharat
>
>
> Alex
>
> > + env->gpr[8] = 0;
> > + env->gpr[9] = 0;
> > env->nip = bi->entry;
> > mmubooke_create_initial_mapping(env);
> > }
> > --
> > 1.7.0.4
> >
> >
>