Re: [RFC v1 12/25] target/arm/kvm-rme: Populate Realm with runtime images

On Tue, Jul 14, 2026 at 08:56:44PM +1000, Gavin Shan wrote:
> On 7/8/26 8:42 AM, Mathieu Poirier wrote:
> > From: Jean-Philippe Brucker <[email protected]>
> > 
> > Once the Realm descriptor has been created, tell KVM to transfer runtime
> > images (kernel, DT, and rootfs) from guest memory to Realm memory.
> > 
> > Signed-off-by: Jean-Philippe Brucker <[email protected]>
> > Signed-off-by: Mathieu Poirier <[email protected]>
> > ---
> >   target/arm/kvm-rme.c | 56 ++++++++++++++++++++++++++++++++++++++++++++
> >   1 file changed, 56 insertions(+)
> > 
> > diff --git a/target/arm/kvm-rme.c b/target/arm/kvm-rme.c
> > index 97ec7c8934c9..58669f4a50f1 100644
> > --- a/target/arm/kvm-rme.c
> > +++ b/target/arm/kvm-rme.c
> > @@ -44,12 +44,68 @@ OBJECT_DEFINE_SIMPLE_TYPE_WITH_INTERFACES(RmeGuest, rme_guest, RME_GUEST,
> >   static RmeGuest *rme_guest;
> > +static int rme_populate_range(const RmeRamRegion *region, bool measure,
> > +                              Error **errp)
> > +{
> > +    int ret;
> > +    void *host_ua;
> > +    hwaddr size = region->size;
> > +    hwaddr base = region->base;
> > +    hwaddr start = QEMU_ALIGN_DOWN(base, RME_PAGE_SIZE);
> > +    hwaddr end = QEMU_ALIGN_UP(base + size, RME_PAGE_SIZE);
> > +    struct kvm_arm_rmi_populate populate_args;
> > +
> > +    host_ua = address_space_map(region->as, base, &size, false,
> > +                                MEMTXATTRS_UNSPECIFIED);
> > +
> > +    populate_args = (struct kvm_arm_rmi_populate) {
> > +        .base = start,
> > +        .size = end - start,
> > +        .source_uaddr = (uintptr_t)host_ua,
> > +        .flags = measure ? KVM_ARM_RMI_POPULATE_FLAGS_MEASURE : 0,
> > +    };
> > +
> > +    while (populate_args.size > 0) {
> > +        ret = kvm_vm_ioctl(kvm_state, KVM_ARM_RMI_POPULATE, &populate_args, 0);
> > +        if (ret) {
> > +            error_setg_errno(errp, -ret,
> > +                "failed to populate realm [0x%"HWADDR_PRIx", 0x%"HWADDR_PRIx")",
> > +                start, end);
> > +            break;
> > +        }
> > +    }
> > +
> > +    address_space_unmap(region->as, host_ua, size, false, 0);
> > +
> > +    return ret;
> > +}
> > +
> 
> Nit: The argument @measure isn't needed as it's always true, passed
> by its only caller rme_populate_range(). I guess it's leftover for
> the earlier host series.
>

I kept this one on purpose.  The KVM_ARM_RMI_POPULATE_FLAGS_MEASURE is used by
the kernel and as such, it is a matter of time before we make that options
available on the cmd line.  I can remove it now but it will come back soon
enough...  
 
> 
> > +static void rme_populate_ram_region(gpointer data, gpointer err)
> > +{
> > +    Error **errp = err;
> > +    const RmeRamRegion *region = data;
> > +
> > +    if (*errp) {
> > +        return;
> > +    }
> > +
> > +    rme_populate_range(region, /* measure */ true, errp);
> > +}
> > +
> >   static void rme_vm_state_change(void *opaque, bool running, RunState state)
> >   {
> > +    Error *errp = NULL;
> > +
> >       if (!running) {
> >           return;
> >       }
> > +    g_slist_foreach(rme_guest->ram_regions, rme_populate_ram_region, &errp);
> > +    g_slist_free_full(g_steal_pointer(&rme_guest->ram_regions), g_free);
> > +    if (errp) {
> > +        return;
> > +    }
> > +
> >       kvm_mark_guest_state_protected();
> >   }
> 
> Thanks,
> Gavin
>