[RFC v2 10/24] target/arm/kvm-rme: Keep track of images loaded in Realm memory

From: Jean-Philippe Brucker <[email protected]>

Add a Rom notifier to keep track of binary blobs loaded in Realm memory.
That way we can deterministically calculate the Realm Initial Measurement (RIM).

Signed-off-by: Jean-Philippe Brucker <[email protected]>
Signed-off-by: Mathieu Poirier <[email protected]>
---
 target/arm/kvm-rme.c | 52 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/target/arm/kvm-rme.c b/target/arm/kvm-rme.c
index 5d6814fcf9e5..10bca9a944ba 100644
--- a/target/arm/kvm-rme.c
+++ b/target/arm/kvm-rme.c
@@ -10,6 +10,7 @@
 
 #include "hw/core/boards.h"
 #include "hw/core/cpu.h"
+#include "hw/core/loader.h"
 #include "kvm_arm.h"
 #include "migration/blocker.h"
 #include "qapi/error.h"
@@ -22,8 +23,18 @@
 #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;
+    AddressSpace *as;
+} RmeRamRegion;
+
 struct RmeGuest {
     ConfidentialGuestSupport parent_obj;
+    Notifier rom_load_notifier;
+    GSList *ram_regions;
 };
 
 OBJECT_DEFINE_SIMPLE_TYPE_WITH_INTERFACES(RmeGuest, rme_guest, RME_GUEST,
@@ -41,6 +52,44 @@ static void rme_vm_state_change(void *opaque, bool running, RunState state)
     kvm_mark_guest_state_protected();
 }
 
+static gint rme_compare_ram_regions(gconstpointer a, gconstpointer b)
+{
+    const RmeRamRegion *ra = a;
+    const RmeRamRegion *rb = b;
+
+    g_assert(ra->base != rb->base);
+    return ra->base < rb->base ? -1 : 1;
+}
+
+static void rme_rom_load_notify(Notifier *notifier, void *data)
+{
+    RmeRamRegion *region;
+    RomLoaderNotifyData *rom = data;
+
+    if (rom->addr == -1) {
+        /*
+         * These blobs (ACPI tables) are not loaded into guest RAM at reset.
+         * Instead the firmware will load them via fw_cfg and measure them
+         * itself.
+         */
+        return;
+    }
+
+    region = g_new0(RmeRamRegion, 1);
+    region->base = rom->addr;
+    region->size = rom->len;
+    region->as = rom->as;
+
+    /*
+     * The Realm Initial Measurement (RIM) depends on the order in which we
+     * initialize and populate the RAM regions. To help a verifier
+     * independently calculate the RIM, sort regions by GPA.
+     */
+    rme_guest->ram_regions = g_slist_insert_sorted(rme_guest->ram_regions,
+                                                   region,
+                                                   rme_compare_ram_regions);
+}
+
 static int kvm_arm_rme_init(ConfidentialGuestSupport *cgs, Error **errp)
 {
     KVMState *s = KVM_STATE(current_accel());
@@ -58,6 +107,9 @@ static int kvm_arm_rme_init(ConfidentialGuestSupport *cgs, Error **errp)
     error_setg(&rme_mig_blocker, "RME: migration is not implemented");
     migrate_add_blocker(&rme_mig_blocker, &error_fatal);
 
+    rme_guest->rom_load_notifier.notify = rme_rom_load_notify;
+    rom_add_load_notifier(&rme_guest->rom_load_notifier);
+
     /*
      * The realm activation is done last, when the VM starts, after all images
      * have been loaded and all vcpus finalized.
-- 
2.43.0