[5/6] target-ppc: Synchronize VPA state with KVM

For PAPR guests, KVM tracks the various areas registered with the
H_REGISTER_VPA hypercall.  For full emulation, of course, these are tracked
within qemu.  At present these values are not synchronized.  This is a
problem for reset (qemu's reset of the VPA address is not pushed to KVM)
and will also be a problem for savevm / migration.

The kernel now supports accessing the VPA state via the ONE_REG interface,
this patch adds code to qemu to use that interface to keep the qemu and
KVM ideas of the VPA state synchronized.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 target-ppc/kvm.c |  105 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 105 insertions(+)

On 24.01.2013, at 04:20, David Gibson wrote:

> For PAPR guests, KVM tracks the various areas registered with the
> H_REGISTER_VPA hypercall.  For full emulation, of course, these are tracked
> within qemu.  At present these values are not synchronized.  This is a
> problem for reset (qemu's reset of the VPA address is not pushed to KVM)
> and will also be a problem for savevm / migration.
> 
> The kernel now supports accessing the VPA state via the ONE_REG interface,
> this patch adds code to qemu to use that interface to keep the qemu and
> KVM ideas of the VPA state synchronized.
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---
> target-ppc/kvm.c |  105 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 105 insertions(+)
> 
> diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
> index 11e123f..8e7a6a9 100644
> --- a/target-ppc/kvm.c
> +++ b/target-ppc/kvm.c
> @@ -635,6 +635,99 @@ static void kvm_get_fp(CPUState *cs)
>     }
> }
> 
> +#if defined(TARGET_PPC64)
> +static void kvm_get_vpa(CPUState *cs)
> +{
> +    PowerPCCPU *cpu = POWERPC_CPU(cs);
> +    CPUPPCState *env = &cpu->env;
> +    struct kvm_one_reg reg;
> +    int ret;
> +
> +    reg.id = KVM_REG_PPC_VPA_ADDR;
> +    reg.addr = (uintptr_t)&env->vpa_addr;
> +    ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
> +    if (ret < 0) {
> +        fprintf(stderr, "Warning: Unable to get VPA address from KVM: %s\n",
> +                strerror(errno));

Thinking about this a bit more, this really is not a warning, but debug output.

> +    }
> +
> +    assert((uintptr_t)&env->slb_shadow_size
> +           == ((uintptr_t)&env->slb_shadow_addr + 8));
> +    reg.id = KVM_REG_PPC_VPA_SLB;
> +    reg.addr = (uintptr_t)&env->slb_shadow_addr;
> +    ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
> +    if (ret < 0) {
> +        fprintf(stderr,
> +                "Warning: Unable to get SLB shadow state from KVM: %s\n",
> +                strerror(errno));
> +    }
> +
> +    assert((uintptr_t)&env->dtl_size == ((uintptr_t)&env->dtl_addr + 8));
> +    reg.id = KVM_REG_PPC_VPA_DTL;
> +    reg.addr = (uintptr_t)&env->dtl_addr;
> +    ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
> +    if (ret < 0) {
> +        fprintf(stderr,
> +                "Warning: Unable to get dispatch trace log state from KVM: %s\n",
> +                strerror(errno));
> +    }
> +}
> +
> +static void kvm_put_vpa(CPUState *cs)
> +{
> +    PowerPCCPU *cpu = POWERPC_CPU(cs);
> +    CPUPPCState *env = &cpu->env;
> +    struct kvm_one_reg reg;
> +    int ret;
> +
> +    /* SLB shadow or DTL can't be registered unless a master VPA is
> +     * registered.  That means when restoring state, if a VPA *is*
> +     * registered, we need to set that up first.  If not, we need to
> +     * deregister the others before deregistering the master VPA */
> +    assert(env->vpa_addr || !(env->slb_shadow_addr || env->dtl_addr));
> +
> +    if (env->vpa_addr) {
> +        reg.id = KVM_REG_PPC_VPA_ADDR;
> +        reg.addr = (uintptr_t)&env->vpa_addr;
> +        ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
> +        if (ret < 0) {
> +            fprintf(stderr, "Warning: Unable to set VPA address to KVM: %s\n",
> +                    strerror(errno));
> +        }
> +    }
> +
> +    assert((uintptr_t)&env->slb_shadow_size
> +           == ((uintptr_t)&env->slb_shadow_addr + 8));
> +    reg.id = KVM_REG_PPC_VPA_SLB;
> +    reg.addr = (uintptr_t)&env->slb_shadow_addr;
> +    ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
> +    if (ret < 0) {
> +        fprintf(stderr, "Warning: Unable to set SLB shadow state to KVM: %s\n",
> +                strerror(errno));
> +    }
> +
> +    assert((uintptr_t)&env->dtl_size == ((uintptr_t)&env->dtl_addr + 8));
> +    reg.id = KVM_REG_PPC_VPA_DTL;
> +    reg.addr = (uintptr_t)&env->dtl_addr;
> +    ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
> +    if (ret < 0) {
> +        fprintf(stderr,
> +                "Warning: Unable to set dispatch trace log state to KVM: %s\n",
> +                strerror(errno));
> +    }
> +
> +    if (!env->vpa_addr) {
> +        reg.id = KVM_REG_PPC_VPA_ADDR;
> +        reg.addr = (uintptr_t)&env->vpa_addr;
> +        ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
> +        if (ret < 0) {
> +            fprintf(stderr, "Warning: Unable to set VPA address to KVM: %s\n",
> +                    strerror(errno));
> +        }
> +    }
> +}
> +#endif /* TARGET_PPC64 */
> +
> int kvm_arch_put_registers(CPUState *cs, int level)
> {
>     PowerPCCPU *cpu = POWERPC_CPU(cs);
> @@ -746,6 +839,12 @@ int kvm_arch_put_registers(CPUState *cs, int level)
> 
>         if (cap_hior && (level >= KVM_PUT_RESET_STATE)) {
>             kvm_put_one_spr(cs, KVM_REG_PPC_HIOR, SPR_HIOR);
> +
> +#ifdef TARGET_PPC64
> +            if (kvm_check_extension(cs->kvm_state, KVM_CAP_PPC_PAPR)) {

This needs to be cached.


Alex

> +                kvm_put_vpa(cs);
> +            }
> +#endif /* TARGET_PPC64 */
>         }
>     }
> 
> @@ -959,6 +1058,12 @@ int kvm_arch_get_registers(CPUState *cs)
>         kvm_get_one_spr(cs, KVM_REG_PPC_PMC6, SPR_PMC6);
>         kvm_get_one_spr(cs, KVM_REG_PPC_PMC7, SPR_PMC7);
>         kvm_get_one_spr(cs, KVM_REG_PPC_PMC8, SPR_PMC8);
> +
> +#ifdef TARGET_PPC64
> +        if (kvm_check_extension(cs->kvm_state, KVM_CAP_PPC_PAPR)) {
> +            kvm_get_vpa(cs);
> +        }
> +#endif
>     }
> 
>     return 0;
> -- 
> 1.7.10.4
>