Re: [Qemu-devel] [RFC PATCH v3] powerpc: add PVR mask support

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 08/15/2013 05:55 PM, Alexander Graf wrote:
> 
> On 15.08.2013, at 09:45, Alexey Kardashevskiy wrote:
> 
>> IBM POWERPC processors encode PVR as a CPU family in higher 16 bits and
>> a CPU version in lower 16 bits. Since there is no significant change
>> in behavior between versions, there is no point to add every single CPU
>> version in QEMU's CPU list. Also, new CPU versions of already supported
>> CPU won't break the existing code.
>>
>> This adds a PVR mask support which means that aliases are replaced with
>> another layer in POWERPC CPU class hierarchy. The patch adds intermediate
>> POWER7, POWER7+ and POWER8 CPU classes and makes use of those in
>> specific versioned POWERPC CPUs.
>>
>> Cc: Andreas Färber <afaerber@suse.de>
>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>>
>> ---
>> Changes:
>> v3:
>> * renamed macros to describe the functionality better
>> * added default PVR value for the powerpc cpu family (what alias used to do)
>>
>> v2:
>> * aliases are replaced with another level in class hierarchy
>> ---
>> target-ppc/cpu-models.c     | 54 ++++++++++++++++++++++++++++++++-------------
>> target-ppc/cpu-models.h     |  7 ++++++
>> target-ppc/cpu-qom.h        |  2 ++
>> target-ppc/translate_init.c |  4 ++--
>> 4 files changed, 50 insertions(+), 17 deletions(-)
>>
>> diff --git a/target-ppc/cpu-models.c b/target-ppc/cpu-models.c
>> index 8dea560..e48004b 100644
>> --- a/target-ppc/cpu-models.c
>> +++ b/target-ppc/cpu-models.c
>> @@ -35,7 +35,8 @@
>> /* PowerPC CPU definitions                                                 */
>> #define POWERPC_DEF_PREFIX(pvr, svr, type)                                  \
>>     glue(glue(glue(glue(pvr, _), svr), _), type)
>> -#define POWERPC_DEF_SVR(_name, _desc, _pvr, _svr, _type)                    \
>> +#define POWERPC_DEF_SVR_MASK(_name, _desc, _pvr, _pvr_mask, _pvr_default,   \
>> +                             _svr, _type, _parent)                          \
>>     static void                                                             \
>>     glue(POWERPC_DEF_PREFIX(_pvr, _svr, _type), _cpu_class_init)            \
>>     (ObjectClass *oc, void *data)                                           \
>> @@ -44,6 +45,8 @@
>>         PowerPCCPUClass *pcc = POWERPC_CPU_CLASS(oc);                       \
>>                                                                             \
>>         pcc->pvr          = _pvr;                                           \
>> +        pcc->pvr_default  = _pvr_default;                                   \
>> +        pcc->pvr_mask     = _pvr_mask;                                      \
>>         pcc->svr          = _svr;                                           \
>>         dc->desc          = _desc;                                          \
>>     }                                                                       \
>> @@ -51,7 +54,7 @@
>>     static const TypeInfo                                                   \
>>     glue(POWERPC_DEF_PREFIX(_pvr, _svr, _type), _cpu_type_info) = {         \
>>         .name       = _name "-" TYPE_POWERPC_CPU,                           \
>> -        .parent     = stringify(_type) "-family-" TYPE_POWERPC_CPU,         \
>> +        .parent     = _parent,                                              \
>>         .class_init =                                                       \
>>             glue(POWERPC_DEF_PREFIX(_pvr, _svr, _type), _cpu_class_init),   \
>>     };                                                                      \
>> @@ -66,9 +69,24 @@
>>     type_init(                                                              \
>>         glue(POWERPC_DEF_PREFIX(_pvr, _svr, _type), _cpu_register_types))
>>
>> +#define POWERPC_DEF_SVR(_name, _desc, _pvr, _svr, _type)                    \
>> +    POWERPC_DEF_SVR_MASK(_name, _desc, _pvr, CPU_POWERPC_DEFAULT_MASK, 0,   \
>> +                         _svr, _type,                                       \
>> +                         stringify(_type) "-family-" TYPE_POWERPC_CPU)
>> +
>> #define POWERPC_DEF(_name, _pvr, _type, _desc)                              \
>>     POWERPC_DEF_SVR(_name, _desc, _pvr, POWERPC_SVR_NONE, _type)
>>
>> +#define POWERPC_DEF_FAMILY(_name, _pvr, _pvr_mask, _pvr_default,            \
>> +                           _type, _desc)                                    \
>> +    POWERPC_DEF_SVR_MASK(_name, _desc, _pvr, _pvr_mask, _pvr_default,       \
>> +                         POWERPC_SVR_NONE, _type,                           \
>> +                         stringify(_type) "-family-" TYPE_POWERPC_CPU)
>> +
>> +#define POWERPC_DEF_FAMILY_MEMBER(_name, _pvr, _type, _desc, _parent)       \
>> +    POWERPC_DEF_SVR_MASK(_name, _desc, _pvr, CPU_POWERPC_DEFAULT_MASK, 0,   \
>> +                         POWERPC_SVR_NONE, _type, _parent)
>> +
>>     /* Embedded PowerPC                                                      */
>>     /* PowerPC 401 family                                                    */
>>     POWERPC_DEF("401",           CPU_POWERPC_401,                    401,
>> @@ -1133,16 +1151,25 @@
>>     POWERPC_DEF("POWER6A",       CPU_POWERPC_POWER6A,                POWER6,
>>                 "POWER6A")
>> #endif
>> -    POWERPC_DEF("POWER7_v2.0",   CPU_POWERPC_POWER7_v20,             POWER7,
>> -                "POWER7 v2.0")
>> -    POWERPC_DEF("POWER7_v2.1",   CPU_POWERPC_POWER7_v21,             POWER7,
>> -                "POWER7 v2.1")
>> -    POWERPC_DEF("POWER7_v2.3",   CPU_POWERPC_POWER7_v23,             POWER7,
>> -                "POWER7 v2.3")
>> -    POWERPC_DEF("POWER7+_v2.1",  CPU_POWERPC_POWER7P_v21,            POWER7,
>> -                "POWER7+ v2.1")
>> -    POWERPC_DEF("POWER8_v1.0",   CPU_POWERPC_POWER8_v10,             POWER8,
>> -                "POWER8 v1.0")
>> +    POWERPC_DEF_FAMILY("POWER7", CPU_POWERPC_POWER7, CPU_POWERPC_POWER7_MASK,
>> +                       CPU_POWERPC_POWER7_v23,
>> +                       POWER7, "POWER7")
>> +    POWERPC_DEF_FAMILY_MEMBER("POWER7_v2.0", CPU_POWERPC_POWER7_v20, POWER7,
>> +                "POWER7 v2.0", "POWER7-" TYPE_POWERPC_CPU)
>> +    POWERPC_DEF_FAMILY_MEMBER("POWER7_v2.1", CPU_POWERPC_POWER7_v21, POWER7,
>> +                "POWER7 v2.1", "POWER7-" TYPE_POWERPC_CPU)
>> +    POWERPC_DEF_FAMILY_MEMBER("POWER7_v2.3", CPU_POWERPC_POWER7_v23, POWER7,
>> +                "POWER7 v2.3", "POWER7-" TYPE_POWERPC_CPU)
>> +    POWERPC_DEF_FAMILY("POWER7+", CPU_POWERPC_POWER7P, CPU_POWERPC_POWER7P_MASK,
>> +                       CPU_POWERPC_POWER7P_v21,
>> +                       POWER7, "POWER7")
>> +    POWERPC_DEF_FAMILY_MEMBER("POWER7+_v2.1", CPU_POWERPC_POWER7P_v21, POWER7,
>> +                "POWER7+ v2.1", "POWER7+-" TYPE_POWERPC_CPU)
>> +    POWERPC_DEF_FAMILY("POWER8", CPU_POWERPC_POWER8, CPU_POWERPC_POWER8_MASK,
>> +                       CPU_POWERPC_POWER8_v10,
>> +                       POWER8, "POWER8")
>> +    POWERPC_DEF_FAMILY_MEMBER("POWER8_v1.0", CPU_POWERPC_POWER8_v10, POWER8,
>> +                              "POWER8 v1.0", "POWER8-" TYPE_POWERPC_CPU)
>>     POWERPC_DEF("970",           CPU_POWERPC_970,                    970,
>>                 "PowerPC 970")
>>     POWERPC_DEF("970fx_v1.0",    CPU_POWERPC_970FX_v10,              970FX,
>> @@ -1389,9 +1416,6 @@ PowerPCCPUAlias ppc_cpu_aliases[] = {
>>     { "POWER3+", "631" },
>>     { "POWER5gr", "POWER5" },
>>     { "POWER5gs", "POWER5+" },
>> -    { "POWER7", "POWER7_v2.3" },
>> -    { "POWER7+", "POWER7+_v2.1" },
>> -    { "POWER8", "POWER8_v1.0" },
>>     { "970fx", "970fx_v3.1" },
>>     { "970mp", "970mp_v1.1" },
>>     { "Apache", "RS64" },
>> diff --git a/target-ppc/cpu-models.h b/target-ppc/cpu-models.h
>> index d9145d1..2233053 100644
>> --- a/target-ppc/cpu-models.h
>> +++ b/target-ppc/cpu-models.h
>> @@ -39,6 +39,7 @@ extern PowerPCCPUAlias ppc_cpu_aliases[];
>> /*****************************************************************************/
>> /* PVR definitions for most known PowerPC                                    */
>> enum {
>> +    CPU_POWERPC_DEFAULT_MASK       = 0xFFFFFFFF,
>>     /* PowerPC 401 family */
>>     /* Generic PowerPC 401 */
>> #define CPU_POWERPC_401              CPU_POWERPC_401G2
>> @@ -557,6 +558,12 @@ enum {
>>     CPU_POWERPC_POWER7_v23         = 0x003F0203,
>>     CPU_POWERPC_POWER7P_v21        = 0x004A0201,
>>     CPU_POWERPC_POWER8_v10         = 0x004B0100,
>> +    CPU_POWERPC_POWER7             = 0x003F0000,
>> +    CPU_POWERPC_POWER7_MASK        = 0xFFFF0000,
>> +    CPU_POWERPC_POWER7P            = 0x004A0000,
>> +    CPU_POWERPC_POWER7P_MASK       = 0xFFFF0000,
>> +    CPU_POWERPC_POWER8             = 0x004B0000,
>> +    CPU_POWERPC_POWER8_MASK        = 0xFFFF0000,
>>     CPU_POWERPC_970                = 0x00390202,
>>     CPU_POWERPC_970FX_v10          = 0x00391100,
>>     CPU_POWERPC_970FX_v20          = 0x003C0200,
>> diff --git a/target-ppc/cpu-qom.h b/target-ppc/cpu-qom.h
>> index f3c710a..a1a712c 100644
>> --- a/target-ppc/cpu-qom.h
>> +++ b/target-ppc/cpu-qom.h
>> @@ -54,6 +54,8 @@ typedef struct PowerPCCPUClass {
>>     void (*parent_reset)(CPUState *cpu);
>>
>>     uint32_t pvr;
>> +    uint32_t pvr_default;
>> +    uint32_t pvr_mask;
>>     uint32_t svr;
>>     uint64_t insns_flags;
>>     uint64_t insns_flags2;
>> diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
>> index 13b290c..e73792d 100644
>> --- a/target-ppc/translate_init.c
>> +++ b/target-ppc/translate_init.c
>> @@ -7309,7 +7309,7 @@ static void init_ppc_proc(PowerPCCPU *cpu)
>> #endif
>>                  SPR_NOACCESS,
>>                  &spr_read_generic, SPR_NOACCESS,
>> -                 pcc->pvr);
>> +                 pcc->pvr_default ? pcc->pvr_default : pcc->pvr);
> 


> This means that -cpu host on a POWER7_v20 system will still return
> POWER7_v23 and thus expose a different CPU inside the guest than
> expected with PR KVM, no?


./qemu-system-ppc64 \
 -cpu \
 POWER7_v2.0 \
 -S \
 -m "1024" \
 -machine "pseries,usb=off" \
 -nographic \
 -vga "none" \
 -enable-kvm \
 -kernel "host.vmlinux" \
 -initrd "1.cpio"

QEMU 1.5.91 monitor - type 'help' for more information
(qemu) info registers
[...]
FPSCR 0000000000000000
 SRR0 0000000000000000  SRR1 0000000000000000    PVR 00000000003f0200
[...]
(qemu)

PVR is 003f0200 which is correct.


> 
> Is there any case where major=0 minor=0 is valid? If not, we could add a
> check in the class constructor and then default to sane values when we
> hit this case. We'll have to add logic there later anyways if we want to
> allow the user to manually specify major and minor numbers.

As I was told and then noticed in the kernel (and sorry for my ignorance if
I am wrong), the lower 16 bits are major/minor numbers only for IBM POWERPC
CPUs and other CPUs may use different number of bits for this purpose. So I
would not parse those numbers and carry them as major/minor version in QEMU
and rather use some fixed sane value for a whole family for the cases when
the user does not really care about the exact chip version.



> 
> 
> Alex
> 
>>     /* Register SVR if it's defined to anything else than POWERPC_SVR_NONE */
>>     if (pcc->svr != POWERPC_SVR_NONE) {
>>         if (pcc->svr & POWERPC_SVR_E500) {
>> @@ -8161,7 +8161,7 @@ static gint ppc_cpu_compare_class_pvr(gconstpointer a, gconstpointer b)
>>     }
>> #endif
>>
>> -    return pcc->pvr == pvr ? 0 : -1;
>> +    return pcc->pvr == (pvr & pcc->pvr_mask) ? 0 : -1;
>> }
>>
>> PowerPCCPUClass *ppc_cpu_class_by_pvr(uint32_t pvr)
>> -- 
>> 1.8.3.2
>>
> 


-- 
Alexey