Re: [Qemu-devel] [Qemu devel v6 PATCH 2/5] msf2: Microsemi Smartfusion2 System Register block.

[sundeep subbaraya]

Hi Philippe,

Ping again :)

Thanks,
Sundeep

On Fri, Jul 21, 2017 at 2:50 PM, sundeep subbaraya <address@hidden>
wrote:

> Hi,
>
> Ping
>
> On Thu, Jul 13, 2017 at 7:51 AM, sundeep subbaraya <address@hidden
> > wrote:
>
>> Hi Phiiippe,
>>
>> Gentle reminder.
>>
>> Thanks,
>> Sundeep
>>
>>
>> On Mon, Jul 10, 2017 at 1:55 PM, sundeep subbaraya <
>> address@hidden> wrote:
>>
>>> Hi Alistair,
>>>
>>> On Fri, Jul 7, 2017 at 10:03 PM, Alistair Francis <address@hidden>
>>> wrote:
>>>
>>>> On Fri, Jul 7, 2017 at 12:08 AM, sundeep subbaraya
>>>> <address@hidden> wrote:
>>>> > Hi Alistair,
>>>> >
>>>> > On Wed, Jul 5, 2017 at 11:36 PM, Alistair Francis <
>>>> address@hidden>
>>>> > wrote:
>>>> >>
>>>> >> On Sun, Jul 2, 2017 at 9:45 PM, Subbaraya Sundeep
>>>> >> <address@hidden> wrote:
>>>> >> > Added Sytem register block of Smartfusion2.
>>>> >> > This block has PLL registers which are accessed by guest.
>>>> >> >
>>>> >> > Signed-off-by: Subbaraya Sundeep <address@hidden>
>>>> >> > ---
>>>> >> >  hw/misc/Makefile.objs         |   1 +
>>>> >> >  hw/misc/msf2-sysreg.c         | 200
>>>> >> > ++++++++++++++++++++++++++++++++++++++++++
>>>> >> >  include/hw/misc/msf2-sysreg.h |  82 +++++++++++++++++
>>>> >> >  3 files changed, 283 insertions(+)
>>>> >> >  create mode 100644 hw/misc/msf2-sysreg.c
>>>> >> >  create mode 100644 include/hw/misc/msf2-sysreg.h
>>>> >> >
>>>> >> > diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
>>>> >> > index c8b4893..0f52354 100644
>>>> >> > --- a/hw/misc/Makefile.objs
>>>> >> > +++ b/hw/misc/Makefile.objs
>>>> >> > @@ -56,3 +56,4 @@ obj-$(CONFIG_EDU) += edu.o
>>>> >> >  obj-$(CONFIG_HYPERV_TESTDEV) += hyperv_testdev.o
>>>> >> >  obj-$(CONFIG_AUX) += auxbus.o
>>>> >> >  obj-$(CONFIG_ASPEED_SOC) += aspeed_scu.o aspeed_sdmc.o
>>>> >> > +obj-$(CONFIG_MSF2) += msf2-sysreg.o
>>>> >> > diff --git a/hw/misc/msf2-sysreg.c b/hw/misc/msf2-sysreg.c
>>>> >> > new file mode 100644
>>>> >> > index 0000000..64ee141
>>>> >> > --- /dev/null
>>>> >> > +++ b/hw/misc/msf2-sysreg.c
>>>> >> > @@ -0,0 +1,200 @@
>>>> >> > +/*
>>>> >> > + * System Register block model of Microsemi SmartFusion2.
>>>> >> > + *
>>>> >> > + * Copyright (c) 2017 Subbaraya Sundeep <address@hidden>
>>>> >> > + *
>>>> >> > + * This program is free software; you can redistribute it and/or
>>>> >> > + * modify it under the terms of the GNU General Public License
>>>> >> > + * as published by the Free Software Foundation; either version
>>>> >> > + * 2 of the License, or (at your option) any later version.
>>>> >> > + *
>>>> >> > + * You should have received a copy of the GNU General Public
>>>> License
>>>> >> > along
>>>> >> > + * with this program; if not, see <http://www.gnu.org/licenses/>.
>>>> >> > + */
>>>> >> > +
>>>> >> > +#include "hw/misc/msf2-sysreg.h"
>>>> >>
>>>> >> Same #include comment from patch 1.
>>>> >
>>>> >
>>>> > Ok will change.
>>>> >>
>>>> >>
>>>> >> > +
>>>> >> > +#ifndef MSF2_SYSREG_ERR_DEBUG
>>>> >> > +#define MSF2_SYSREG_ERR_DEBUG  0
>>>> >> > +#endif
>>>> >> > +
>>>> >> > +#define DB_PRINT_L(lvl, fmt, args...) do { \
>>>> >> > +    if (MSF2_SYSREG_ERR_DEBUG >= lvl) { \
>>>> >> > +        qemu_log("%s: " fmt "\n", __func__, ## args); \
>>>> >> > +    } \
>>>> >> > +} while (0);
>>>> >> > +
>>>> >> > +#define DB_PRINT(fmt, args...) DB_PRINT_L(1, fmt, ## args)
>>>> >> > +
>>>> >> > +static inline int msf2_divbits(uint32_t div)
>>>> >> > +{
>>>> >> > +    int ret = 0;
>>>> >> > +
>>>> >> > +    switch (div) {
>>>> >> > +    case 1:
>>>> >> > +        ret = 0;
>>>> >> > +        break;
>>>> >> > +    case 2:
>>>> >> > +        ret = 1;
>>>> >> > +        break;
>>>> >> > +    case 4:
>>>> >> > +        ret = 2;
>>>> >> > +        break;
>>>> >> > +    case 8:
>>>> >> > +        ret = 4;
>>>> >> > +        break;
>>>> >> > +    case 16:
>>>> >> > +        ret = 5;
>>>> >> > +        break;
>>>> >> > +    case 32:
>>>> >> > +        ret = 6;
>>>> >> > +        break;
>>>> >> > +    default:
>>>> >> > +        break;
>>>> >> > +    }
>>>> >> > +
>>>> >> > +    return ret;
>>>> >> > +}
>>>> >> > +
>>>> >> > +static void msf2_sysreg_reset(DeviceState *d)
>>>> >> > +{
>>>> >> > +    MSF2SysregState *s = MSF2_SYSREG(d);
>>>> >> > +
>>>> >> > +    DB_PRINT("RESET");
>>>> >> > +
>>>> >> > +    s->regs[MSSDDR_PLL_STATUS_LOW_CR] = 0x021A2358;
>>>> >> > +    s->regs[MSSDDR_PLL_STATUS] = 0x3;
>>>> >> > +    s->regs[MSSDDR_FACC1_CR] = msf2_divbits(s->apb0div) << 5 |
>>>> >> > +                               msf2_divbits(s->apb1div) << 2;
>>>> >> > +}
>>>> >> > +
>>>> >> > +static uint64_t msf2_sysreg_read(void *opaque, hwaddr offset,
>>>> >> > +    unsigned size)
>>>> >> > +{
>>>> >> > +    MSF2SysregState *s = opaque;
>>>> >> > +    offset /= 4;
>>>> >>
>>>> >> Probably best to use a bitshift.
>>>> >
>>>> >
>>>> > Ok will change.
>>>> >>
>>>> >>
>>>> >> > +    uint32_t ret = 0;
>>>> >> > +
>>>> >> > +    if (offset < ARRAY_SIZE(s->regs)) {
>>>> >> > +        ret = s->regs[offset];
>>>> >> > +        DB_PRINT("addr: 0x%08" HWADDR_PRIx " data: 0x%08" PRIx32,
>>>> >> > +                    offset * 4, ret);
>>>> >>
>>>> >> Bitshift here as well.
>>>> >
>>>> >
>>>> > Ok will change.
>>>> >>
>>>> >>
>>>> >> > +    } else {
>>>> >> > +        qemu_log_mask(LOG_GUEST_ERROR,
>>>> >> > +                    "%s: Bad offset 0x%08" HWADDR_PRIx "\n",
>>>> __func__,
>>>> >> > +                    offset * 4);
>>>> >> > +    }
>>>> >> > +
>>>> >> > +    return ret;
>>>> >> > +}
>>>> >> > +
>>>> >> > +static void msf2_sysreg_write(void *opaque, hwaddr offset,
>>>> >> > +                          uint64_t val, unsigned size)
>>>> >> > +{
>>>> >> > +    MSF2SysregState *s = (MSF2SysregState *)opaque;
>>>> >> > +    uint32_t newval = val;
>>>> >> > +    uint32_t oldval;
>>>> >> > +
>>>> >> > +    DB_PRINT("addr: 0x%08" HWADDR_PRIx " data: 0x%08" PRIx64,
>>>> >> > +            offset, val);
>>>> >> > +
>>>> >> > +    offset /= 4;
>>>> >>
>>>> >> Same here
>>>> >
>>>> >
>>>> > Ok will change
>>>> >>
>>>> >>
>>>> >> > +
>>>> >> > +    switch (offset) {
>>>> >> > +    case MSSDDR_PLL_STATUS:
>>>> >> > +        break;
>>>> >> > +
>>>> >> > +    case ESRAM_CR:
>>>> >> > +        oldval = s->regs[ESRAM_CR];
>>>> >> > +        if (oldval ^ newval) {
>>>> >> > +            qemu_log_mask(LOG_GUEST_ERROR,
>>>> >> > +                       TYPE_MSF2_SYSREG": eSRAM remapping not
>>>> >> > supported\n");
>>>> >> > +            abort();
>>>> >>
>>>> >> The guest should not be able to kill QEMU, a guest error should never
>>>> >> result in an abort.
>>>> >
>>>> >
>>>> > Philippe suggested to abort because:
>>>> > If guest tries to remap since firmware do a remap, the code flow will
>>>> be
>>>> > completely wrong.
>>>> > Reporting a GUEST_ERROR here is not enough since code flow continuing
>>>> would
>>>> > be
>>>> > pretty hard to understand/debug.
>>>>
>>>> I don't see how it will be that hard to debug as QEMU will tell you
>>>> that the guest is doing something wrong.
>>>>
>>>> You can't allow the guest to abort or exit QEMU. It's a security
>>>> liability issue and specifically mentioned as not allowed:
>>>> https://github.com/qemu/qemu/blob/master/HACKING#L230
>>>>
>>>> Ok. Lets hear from Philippe. Philippe?
>>>
>>> Thanks,
>>> Sundeep
>>>
>>>
>>>> Thanks,
>>>> Alistair
>>>>
>>>> > We decided to abort for now.
>>>>
>>>
>>>
>>
>