Re: [RFC v4 04/24] target/arm/kvm-rme: Add mechanic to initialize realms

[Gavin Shan <gshan@redhat.com>]

On 9/4/26 5:35 AM, Mathieu Poirier wrote:
> Initialise an @rme_guest object and install a handler to get notified
> when the Realm is ready to start.  That way we can finish reading the
> Realm once we know everything is in place.
> 
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@linaro.org>
> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> ---
>   target/arm/kvm-rme.c | 51 ++++++++++++++++++++++++++++++++++++++++++++
>   target/arm/kvm.c     | 15 +++++++++++--
>   2 files changed, 64 insertions(+), 2 deletions(-)
> 
> diff --git a/target/arm/kvm-rme.c b/target/arm/kvm-rme.c
> index 42e1d1e7b859..a4a5e195c196 100644
> --- a/target/arm/kvm-rme.c
> +++ b/target/arm/kvm-rme.c
> @@ -13,6 +13,7 @@
>   #include "kvm_arm.h"
>   #include "migration/blocker.h"
>   #include "qapi/error.h"
> +#include "qemu/error-report.h"
>   #include "qom/object_interfaces.h"
>   #include "system/confidential-guest-support.h"
>   #include "system/kvm.h"
> @@ -29,12 +30,62 @@ OBJECT_DEFINE_SIMPLE_TYPE_WITH_INTERFACES(RmeGuest, rme_guest, RME_GUEST,
>                                             CONFIDENTIAL_GUEST_SUPPORT,
>                                             { TYPE_USER_CREATABLE }, { })
>   
> +static RmeGuest *rme_guest;
> +
> +static void rme_vm_state_change(void *opaque, bool running, RunState state)
> +{
> +    if (!running) {
> +        return;
> +    }
> +
> +    kvm_mark_guest_state_protected();
> +}
> +
> +static int kvm_arm_rme_init(ConfidentialGuestSupport *cgs, Error **errp)
> +{
> +    KVMState *s = KVM_STATE(current_accel());
> +    static Error *rme_mig_blocker;
> +
> +    if (!rme_guest) {
> +        return 0;
> +    }
> +
> +    if (!kvm_vm_check_extension(s, KVM_CAP_ARM_RMI)) {
> +        error_setg(errp, "VM doesn't support Realms");
> +        return -ENODEV;
> +    }
> +
> +    error_setg(&rme_mig_blocker, "RME: migration is not implemented");
> +    migrate_add_blocker(&rme_mig_blocker, &error_fatal);
> +
> +    /*
> +     * The realm activation is done last, when the VM starts, after all images
> +     * have been loaded and all vcpus finalized.
> +     */
> +    qemu_add_vm_change_state_handler(rme_vm_state_change, NULL);
> +
> +    cgs->require_guest_memfd = true;
> +    cgs->ready = true;
> +    return 0;
> +}
> +
>   static void rme_guest_class_init(ObjectClass *oc, const void *data)
>   {
> +    ConfidentialGuestSupportClass *klass = CONFIDENTIAL_GUEST_SUPPORT_CLASS(oc);
> +
> +    klass->kvm_init = kvm_arm_rme_init;
>   }
>   
>   static void rme_guest_init(Object *obj)
>   {
> +    ConfidentialGuestSupport *cgs = CONFIDENTIAL_GUEST_SUPPORT(obj);
> +
> +    if (rme_guest) {
> +        error_report("a single instance of RmeGuest is supported");
> +        exit(1);
> +    }
> +    rme_guest = RME_GUEST(obj);
> +    cgs->allow_convert_in_place = true;
>   }
>   
>   static void rme_guest_finalize(Object *obj)
> diff --git a/target/arm/kvm.c b/target/arm/kvm.c
> index ed99be7fd80c..401a6f669cbb 100644
> --- a/target/arm/kvm.c
> +++ b/target/arm/kvm.c
> @@ -33,6 +33,7 @@
>   #include "hw/pci/pci.h"
>   #include "exec/memattrs.h"
>   #include "system/address-spaces.h"
> +#include "system/confidential-guest-support.h"
>   #include "gdbstub/enums.h"
>   #include "hw/core/boards.h"
>   #include "hw/core/irq.h"
> @@ -596,7 +597,8 @@ int kvm_arch_get_default_type(MachineState *ms)
>   
>   int kvm_arch_init(MachineState *ms, KVMState *s)
>   {
> -    int ret;
> +    Error *local_err = NULL;
> +    int ret = 0;
>       /* For ARM interrupt delivery is always asynchronous,
>        * whether we are using an in-kernel VGIC or not.
>        */
> @@ -610,6 +612,15 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
>   
>       cap_has_mp_state = kvm_check_extension(s, KVM_CAP_MP_STATE);
>   
> +    /* Initialize confidential guest (Realm) if needed */
> +    if (ms->cgs) {
> +        ret = confidential_guest_kvm_init(ms->cgs, &local_err);
> +            if (ret < 0) {
            ^^^^^

            Code alignment issue here.

> +                error_report_err(local_err);
> +                return ret;
> +        }
> +    }
> +
>       /* Check whether user space can specify guest syndrome value */
>       cap_has_inject_serror_esr =
>           kvm_check_extension(s, KVM_CAP_ARM_INJECT_SERROR_ESR);
> @@ -660,7 +671,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
>       hw_breakpoints = g_array_sized_new(true, true,
>                                          sizeof(HWBreakpoint), max_hw_bps);
>   
> -    return 0;
> +    return ret;
>   }
>   
>   unsigned long kvm_arch_vcpu_id(CPUState *cpu)

Thanks,
Gavin