Re: [RFC v1 09/25] target/arm/kvm-rme: Initialise Realm Initial Address space

On Fri, Jul 10, 2026 at 09:44:11AM +1000, Gavin Shan wrote:
> Hi Mathieu,
> 
> On 7/8/26 8:42 AM, Mathieu Poirier wrote:
> > From: Jean-Philippe Brucker <[email protected]>
> > 
> > Initialise the Realm's initial physical address space based on
> > the VM's configuration.
> > 
> > Signed-off-by: Jean-Philippe Brucker <[email protected]>
> > Signed-off-by: Mathieu Poirier <[email protected]>
> > ---
> >   hw/arm/boot.c         |  4 ++++
> >   target/arm/kvm-rme.c  | 18 ++++++++++++++++++
> >   target/arm/kvm-stub.c |  4 ++++
> >   target/arm/kvm_arm.h  | 10 ++++++++++
> >   4 files changed, 36 insertions(+)
> > 
> 
> Thanks for the posting.
> 
> If RmeGuest::init_ram isn't needed in the future, this patch can be dropped.
> There is no API exposed from (v14) host series to initialize RIPAS for the
> specified IPA range, as we did in the earlier revisions. So this patch was
> added for the earlier host serieses, not for (v14) host series any more?

I scrapped it.  There is a lot of churn in the kernel baselines and it is easy
to overlook a patch.

> 
> Thanks,
> Gavin
> 
> > diff --git a/hw/arm/boot.c b/hw/arm/boot.c
> > index 9b7553dde5e1..bcab21d349b4 100644
> > --- a/hw/arm/boot.c
> > +++ b/hw/arm/boot.c
> > @@ -32,6 +32,7 @@
> >   #include "qemu/option.h"
> >   #include "qemu/units.h"
> >   #include "qemu/bswap.h"
> > +#include "kvm_arm.h"
> >   /* Kernel boot protocol is specified in the kernel docs
> >    * Documentation/arm/Booting and Documentation/arm64/booting.txt
> > @@ -1210,6 +1211,9 @@ void arm_load_kernel(ARMCPU *cpu, MachineState *ms, struct arm_boot_info *info)
> >       /* We assume the CPU passed as argument is the primary CPU.  */
> >       info->primary_cpu = cpu;
> > +    /* Mark all Realm memory as RAM */
> > +    kvm_arm_rme_init_guest_ram(info->loader_start, info->ram_size);
> > +
> >       /* Load the kernel.  */
> >       if (!info->kernel_filename || info->firmware_loaded) {
> >           arm_setup_firmware_boot(cpu, info);
> > diff --git a/target/arm/kvm-rme.c b/target/arm/kvm-rme.c
> > index f763d5ed6199..697e7d507f0d 100644
> > --- a/target/arm/kvm-rme.c
> > +++ b/target/arm/kvm-rme.c
> > @@ -22,8 +22,16 @@
> >   #define TYPE_RME_GUEST "rme-guest"
> >   OBJECT_DECLARE_SIMPLE_TYPE(RmeGuest, RME_GUEST)
> > +#define RME_PAGE_SIZE qemu_real_host_page_size()
> > +
> > +typedef struct {
> > +    hwaddr base;
> > +    hwaddr size;
> > +} RmeRamRegion;
> > +
> >   struct RmeGuest {
> >       ConfidentialGuestSupport parent_obj;
> > +    RmeRamRegion init_ram;
> >   };
> >   OBJECT_DEFINE_SIMPLE_TYPE_WITH_INTERFACES(RmeGuest, rme_guest, RME_GUEST,
> > @@ -91,6 +99,16 @@ int kvm_arm_rme_init(MachineState *ms, KVMState *s)
> >       return 0;
> >   }
> > +void kvm_arm_rme_init_guest_ram(hwaddr base, size_t size)
> > +{
> > +    if (!rme_guest) {
> > +        return;
> > +    }
> > +
> > +    rme_guest->init_ram.base = base;
> > +    rme_guest->init_ram.size = size;
> > +}
> > +
> >   void kvm_arm_rme_vcpu_init(ARMCPU *cpu)
> >   {
> >       if (!rme_guest) {
> > diff --git a/target/arm/kvm-stub.c b/target/arm/kvm-stub.c
> > index 6d52f172c5df..790e1940fd8a 100644
> > --- a/target/arm/kvm-stub.c
> > +++ b/target/arm/kvm-stub.c
> > @@ -42,6 +42,10 @@ bool kvm_arm_el2_supported(void)
> >       return false;
> >   }
> > +void kvm_arm_rme_init_guest_ram(hwaddr base, size_t size)
> > +{
> > +}
> > +
> >   /*
> >    * These functions should never actually be called without KVM support.
> >    */
> > diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h
> > index 65ec1b970606..c7dc45595159 100644
> > --- a/target/arm/kvm_arm.h
> > +++ b/target/arm/kvm_arm.h
> > @@ -267,4 +267,14 @@ void kvm_arm_rme_vcpu_init(ARMCPU *cpu);
> >    */
> >   int kvm_arm_rme_vm_type(void);
> > +/*
> > + * kvm_arm_rme_init_guest_ram
> > + * @base: base address of RAM
> > + * @size: size of RAM
> > + *
> > + * If the user requested a Realm, set the base and size of guest RAM, in order
> > + * to initialize the Realm IPA space.
> > + */
> > +void kvm_arm_rme_init_guest_ram(hwaddr base, size_t size);
> > +
> >   #endif
>