Re: [Qemu-devel] [PATCH 1/5] target-ppc: Synchronize VPA state with KVM

[Alexander Graf <agraf@suse.de>]

On 14.03.2013, at 02:53, 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 |  121 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 121 insertions(+)
> 
> diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
> index 67f3f42..f5710b7 100644
> --- a/target-ppc/kvm.c
> +++ b/target-ppc/kvm.c
> @@ -63,6 +63,7 @@ static int cap_ppc_rma;
> static int cap_spapr_tce;
> static int cap_hior;
> static int cap_one_reg;
> +static int cap_papr;
> 
> /* XXX We have a race condition where we actually have a level triggered
>  *     interrupt, but the infrastructure can't expose that yet, so the guest
> @@ -95,6 +96,8 @@ int kvm_arch_init(KVMState *s)
>     cap_spapr_tce = kvm_check_extension(s, KVM_CAP_SPAPR_TCE);
>     cap_one_reg = kvm_check_extension(s, KVM_CAP_ONE_REG);
>     cap_hior = kvm_check_extension(s, KVM_CAP_PPC_HIOR);
> +    /* Note: we don't set cap_papr here, because this capability is
> +     * only activated after this by kvmppc_set_papr() */
> 
>     if (!cap_interrupt_level) {
>         fprintf(stderr, "KVM: Couldn't find level irq capability. Expect the "
> @@ -652,6 +655,103 @@ static int kvm_get_fp(CPUState *cs)
>     return 0;
> }
> 
> +#if defined(TARGET_PPC64)
> +static int 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) {
> +        dprintf("Unable to get VPA address from KVM: %s\n", strerror(errno));
> +        return ret;
> +    }
> +
> +    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) {
> +        dprintf("Unable to get SLB shadow state from KVM: %s\n",
> +                strerror(errno));
> +        return ret;
> +    }
> +
> +    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) {
> +        dprintf("Unable to get dispatch trace log state from KVM: %s\n",
> +                strerror(errno));
> +        return ret;
> +    }
> +
> +    return 0;
> +}
> +
> +static int 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) {
> +            dprintf("Unable to set VPA address to KVM: %s\n", strerror(errno));
> +            return ret;
> +        }
> +    }
> +
> +    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) {
> +        dprintf("Unable to set SLB shadow state to KVM: %s\n", strerror(errno));
> +        return ret;
> +    }
> +
> +    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) {
> +        dprintf("Unable to set dispatch trace log state to KVM: %s\n",
> +                strerror(errno));
> +        return ret;
> +    }
> +
> +    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) {
> +            dprintf("Unable to set VPA address to KVM: %s\n", strerror(errno));
> +            return ret;
> +        }
> +    }
> +
> +    return 0;
> +}
> +#endif /* TARGET_PPC64 */
> +
> int kvm_arch_put_registers(CPUState *cs, int level)
> {
>     PowerPCCPU *cpu = POWERPC_CPU(cs);
> @@ -752,6 +852,14 @@ int kvm_arch_put_registers(CPUState *cs, int level)
>                 kvm_put_one_spr(cs, id, i);
>             }
>         }
> +
> +#ifdef TARGET_PPC64
> +        if (cap_papr) {
> +            if (kvm_put_vpa(cs) < 0) {
> +                dprintf("Warning: Unable to set VPA information to KVM\n");
> +            }
> +        }
> +#endif /* TARGET_PPC64 */
>     }
> 
>     return ret;
> @@ -953,6 +1061,15 @@ int kvm_arch_get_registers(CPUState *cs)
>                 kvm_get_one_spr(cs, id, i);
>             }
>         }
> +
> +#ifdef TARGET_PPC64
> +        if (cap_papr) {
> +            if (kvm_get_vpa(cs) < 0) {
> +                fprintf(stderr,
> +                        "Warning: Unable to get VPA information from KVM\n");

This will give odd warnings on old HV KVM systems and PR KVM, no?


Alex

> +            }
> +        }
> +#endif
>     }
> 
>     return 0;
> @@ -1299,6 +1416,10 @@ void kvmppc_set_papr(PowerPCCPU *cpu)
>     if (ret) {
>         cpu_abort(env, "This KVM version does not support PAPR\n");
>     }
> +
> +    /* Update the capability flag so we sync the right information
> +     * with kvm */
> +    cap_papr = 1;
> }
> 
> void kvmppc_set_mpic_proxy(PowerPCCPU *cpu, int mpic_proxy)
> -- 
> 1.7.10.4
>