Re: [Qemu-devel] [PATCH 3/6] s390/kvm: diag288 instruction interception and handling

[Alexander Graf <agraf@suse.de>]

On 04/17/2015 09:52 AM, Cornelia Huck wrote:
> From: Xu Wang <gesaint@linux.vnet.ibm.com>
>
> Intercept the diag288 requests from kvm guests, and hand the
> requested command to the diag288 watchdog device for further
> handling.
>
> Signed-off-by: Xu Wang <gesaint@linux.vnet.ibm.com>
> Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

We're getting a lot of random devices allocating diag intercepts. Can't 
we make this an actual interface, similar to the hypercall registration 
on sPAPR?


Alex

> ---
>   target-s390x/cpu.h         |  1 +
>   target-s390x/kvm.c         | 18 ++++++++++++++++++
>   target-s390x/misc_helper.c | 33 +++++++++++++++++++++++++++++++++
>   3 files changed, 52 insertions(+)
>
> diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
> index ba7d250..f5cafc3 100644
> --- a/target-s390x/cpu.h
> +++ b/target-s390x/cpu.h
> @@ -1059,6 +1059,7 @@ uint32_t set_cc_nz_f128(float128 v);
>   
>   /* misc_helper.c */
>   #ifndef CONFIG_USER_ONLY
> +int handle_diag_288(CPUS390XState *env, uint64_t r1, uint64_t r3);
>   void handle_diag_308(CPUS390XState *env, uint64_t r1, uint64_t r3);
>   #endif
>   void program_interrupt(CPUS390XState *env, uint32_t code, int ilen);
> diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
> index b8703b8..32ed4ab 100644
> --- a/target-s390x/kvm.c
> +++ b/target-s390x/kvm.c
> @@ -97,6 +97,7 @@
>   #define PRIV_E3_MPCIFC                  0xd0
>   #define PRIV_E3_STPCIFC                 0xd4
>   
> +#define DIAG_TIMEREVENT                 0x288
>   #define DIAG_IPL                        0x308
>   #define DIAG_KVM_HYPERCALL              0x500
>   #define DIAG_KVM_BREAKPOINT             0x501
> @@ -1215,6 +1216,20 @@ static int handle_hypercall(S390CPU *cpu, struct kvm_run *run)
>       return ret;
>   }
>   
> +static void kvm_handle_diag_288(S390CPU *cpu, struct kvm_run *run)
> +{
> +    uint64_t r1, r3;
> +    int rc;
> +
> +    cpu_synchronize_state(CPU(cpu));
> +    r1 = (run->s390_sieic.ipa & 0x00f0) >> 4;
> +    r3 = run->s390_sieic.ipa & 0x000f;
> +    rc = handle_diag_288(&cpu->env, r1, r3);
> +    if (rc == -1) {
> +        enter_pgmcheck(cpu, PGM_SPECIFICATION);
> +    }
> +}
> +
>   static void kvm_handle_diag_308(S390CPU *cpu, struct kvm_run *run)
>   {
>       uint64_t r1, r3;
> @@ -1254,6 +1269,9 @@ static int handle_diag(S390CPU *cpu, struct kvm_run *run, uint32_t ipb)
>        */
>       func_code = decode_basedisp_rs(&cpu->env, ipb, NULL) & DIAG_KVM_CODE_MASK;
>       switch (func_code) {
> +    case DIAG_TIMEREVENT:
> +        kvm_handle_diag_288(cpu, run);
> +        break;
>       case DIAG_IPL:
>           kvm_handle_diag_308(cpu, run);
>           break;
> diff --git a/target-s390x/misc_helper.c b/target-s390x/misc_helper.c
> index e1007fa..88d96bf 100644
> --- a/target-s390x/misc_helper.c
> +++ b/target-s390x/misc_helper.c
> @@ -30,6 +30,7 @@
>   #include <linux/kvm.h>
>   #endif
>   #include "exec/cpu_ldst.h"
> +#include "hw/watchdog/wdt_diag288.h"
>   
>   #if !defined(CONFIG_USER_ONLY)
>   #include "sysemu/cpus.h"
> @@ -153,6 +154,38 @@ static int load_normal_reset(S390CPU *cpu)
>       return 0;
>   }
>   
> +int handle_diag_288(CPUS390XState *env, uint64_t r1, uint64_t r3)
> +{
> +    uint64_t func = env->regs[r1];
> +    uint64_t timeout = env->regs[r1 + 1];
> +    uint64_t action = env->regs[r3];
> +    Object *obj;
> +    DIAG288State *diag288;
> +    DIAG288Class *diag288_class;
> +
> +    if (r1 % 2) {
> +        return -1;
> +    }
> +
> +    if (action != 0) {
> +        return -1;
> +    }
> +
> +    /* Timeout must be more than 15 seconds except for timer deletion */
> +    if (func != WDT_DIAG288_CANCEL && timeout < 15) {
> +        return -1;
> +    }
> +
> +    obj = object_resolve_path_type("", TYPE_WDT_DIAG288, NULL);
> +    if (!obj) {
> +        return -1;
> +    }
> +
> +    diag288 = DIAG288(obj);
> +    diag288_class = DIAG288_GET_CLASS(diag288);
> +    return diag288_class->handle_timer(diag288, func, timeout);
> +}
> +
>   #define DIAG_308_RC_OK              0x0001
>   #define DIAG_308_RC_NO_CONF         0x0102
>   #define DIAG_308_RC_INVALID         0x0402